KR102778378B1 - Chip-Scale Atomic Magnetometer - Google Patents

Abstract

According to one embodiment of the present invention, an atomic magnetometer comprises: a substrate including a cavity having a first inclined side surface having a first inclined angle in a first direction and a second inclined side surface inclined at a second angle in a second direction; a lower transparent substrate disposed on a lower surface of the substrate and covering the cavity; a first mirror surface disposed under the lower transparent substrate and inclined at the first inclined angle; a first light source disposed under the lower transparent substrate and providing a pump beam to the first mirror surface; a second mirror surface disposed under the lower transparent substrate and inclined at the second inclined angle; and a second light source disposed under the lower transparent substrate and providing a probe beam to the second mirror surface.

Description

Chip-Scale Atomic Magnetometer

The present invention relates to an atomic magnetometer, and more particularly, to an atomic magnetometer having an alkali metal vapor cell in which a cavity is formed in a silicon substrate by wet etching.

The silicon substrate provides a cavity with a 54.7 degree slope due to the wet etching of the crystal structure of the substrate.

A pump beam or probe beam incident perpendicular to the substrate cannot form a stable beam path if it is reflected from an inclined surface of 54.7 degrees.

The technical problem to be solved by the present invention is to provide an atomic magnetometer having a compact structure.

The technical problem to be solved by the present invention is to stably provide optical paths of a pump beam and a probe beam to a vapor cell using a MEMS (Micro Electro Mechanical Systems) process.

According to one embodiment of the present invention, an atomic magnetometer comprises: a substrate including a cavity having a first inclined side surface having a first inclined angle in a first direction and a second inclined side surface inclined at a second angle in a second direction; a lower transparent substrate disposed on a lower surface of the substrate and covering the cavity; a first mirror surface disposed under the lower transparent substrate and inclined at the first inclined angle; a first light source disposed under the lower transparent substrate and providing a pump beam to the first mirror surface; a second mirror surface disposed under the lower transparent substrate and inclined at the second inclined angle; and a second light source disposed under the lower transparent substrate and providing a probe beam to the second mirror surface. The first mirror surface is parallel to the first inclined side surface, the second mirror surface is parallel to the second inclined side surface, the pump beam is incident parallel to the first direction and is reflected from the first mirror surface and the first inclined side surface of the cavity and travels in the first direction within the cavity to have a “Z” shaped beam path. The probe beam is incident parallel to the second direction and is reflected from the second mirror surface and the second inclined side surface of the cavity and travels in the second direction within the cavity to have a “Z” shaped beam path.

According to one embodiment of the present invention, the substrate may be a silicon substrate, and the first inclination angle and the second inclination angle may be 54.7 degrees.

According to one embodiment of the present invention, the device may further include an upper transparent substrate disposed on an upper surface of the substrate and covering the cavity.

According to one embodiment of the present invention, the device may further include a first mirror made of silicon and providing the first mirror surface; a second mirror made of silicon and providing the second mirror surface; and a base substrate on which the first mirror and the second mirror are arranged.

According to one embodiment of the present invention, a first right-angle prism disposed on the first light source; and a second right-angle prism disposed on the second light source may be further included. The first light source may be disposed on the base substrate, the second light source may be disposed on the base substrate, and the pump beam may be totally reflected once by the first right-angle prism and may be incident in a first direction parallel to the first mirror surface, and the probe beam may be totally reflected once by the second right-angle prism and may be incident in a second direction parallel to the second mirror surface.

According to one embodiment of the present invention, the device may further include a photo-thermal structure disposed below the lower transparent substrate; and a heating light source that irradiates light to the photo-thermal structure.

According to one embodiment of the present invention, the photo-thermal structure may have a surface plasmon resonance structure.

According to one embodiment of the present invention, the photo-thermal structure includes a plurality of pillars protruding from the lower transparent substrate; metal nanoparticles formed on upper surfaces and side surfaces of the pillars and on the lower transparent substrate between the pillars; and the metal nanoparticles may be hemispherical.

According to one embodiment of the present invention, the device further comprises a first quarter wave plate disposed on the lower transparent substrate, wherein the first quarter wave plate can be disposed on an optical path of the pump beam.

According to one embodiment of the present invention, the first 1/4 wavelength plate may include a plurality of elliptical columns protruding from the lower transparent substrate and arranged at regular intervals. The elliptical columns may be made of a silicon material.

According to one embodiment of the present invention, the device may further include a polarization beam splitter disposed on the lower transparent substrate; and a first photodetector and a second photodetector disposed below the polarization beam splitter. The polarization beam splitter may split the probe beam traveling in the second direction according to a polarization state and provide the split beam to the first photodetector and the second photodetector, respectively.

According to one embodiment of the present invention, the polarizing beam splitter may include a plurality of pillars regularly arranged and protruding from the lower transparent substrate. The plurality of pillars may be silicon having cross-sectional shapes of different sizes.

According to one embodiment of the present invention, the device may further include a base substrate on which a first mirror providing the first mirror surface and a second mirror providing the second mirror surface are disposed; and a spacer disposed between the base substrate and the lower transparent substrate.

According to one embodiment of the present invention, the invention may further include: a base substrate on which a first mirror providing the first mirror surface and a second mirror providing the second mirror surface are arranged; a third mirror arranged on the base substrate and providing a third mirror surface inclined at the first inclination angle; and a fourth mirror arranged on the base substrate and providing a fourth mirror surface inclined at the second inclination angle. An optical path of the pump beam may proceed through the first mirror surface, the pair of first inclined sides, and the third mirror surface, and an optical path of the probe beam may proceed through the second mirror surface, the pair of second inclined sides, and the fourth mirror surface.

According to one embodiment of the present invention, the present invention may further include a polarizing beam splitter provided with a probe beam reflected from the fourth mirror surface and arranged on the base substrate; a first photodetector arranged on one side of the polarizing beam splitter; and a second photodetector arranged on the other side of the polarizing beam splitter.

According to one embodiment of the present invention, a base substrate having a first mirror providing the first mirror surface and a second mirror providing the second mirror surface disposed thereon; a first waveguide continuously connected to the first mirror surface and disposed on the base substrate; and a second waveguide continuously connected to the second mirror surface and disposed on the base substrate; The pump beam may be incident on the first waveguide, reflected from the first mirror surface, and incident on the first inclined side surface, and the probe beam may be incident on the second waveguide, reflected from the second mirror surface, and incident on the second inclined side surface.

According to one embodiment of the present invention, the invention may further include: a third mirror disposed on the base substrate and providing a third mirror surface inclined at the first inclination angle; a fourth mirror disposed on the base substrate and providing a fourth mirror surface inclined at the second inclination angle; a third waveguide continuously connected to the third mirror surface; and a fourth waveguide continuously connected to the fourth mirror surface. An optical path of the pump beam may proceed through the first waveguide, the first mirror surface, the pair of first inclination sides, and the third mirror surface, and the third waveguide, and an optical path of the probe beam may proceed through the second waveguide, the second mirror surface, the pair of second inclination sides, and the fourth mirror surface, and the fourth waveguide.

According to one embodiment of the present invention, one end of the first waveguide is a prism structure having a 45-degree inclined structure, the first light source is disposed on the base substrate, the pump beam is totally reflected once by the prism structure of the first waveguide and proceeds to the first mirror surface, and one end of the second waveguide is a prism structure having a 45-degree inclined structure, the second light source is disposed on the base substrate, and the probe beam can be totally reflected once by the prism structure of the second waveguide and proceeds to the second mirror surface.

According to one embodiment of the present invention, a first waveguide including the first mirror surface at one end and disposed on the base substrate may be further included; and a second waveguide including the second mirror surface at one end and disposed on the base substrate. The pump beam may be incident on the first waveguide, reflected by the first mirror surface, and incident on the first inclined side surface, and the probe beam may be incident on the second waveguide, reflected by the second mirror surface, and incident on the second inclined side surface.

According to one embodiment of the present invention, the other end of the first waveguide has a right-angle prism structure, the other end of the second waveguide has a right-angle prism structure, the first light source may be disposed on the base substrate, and the second light source may be disposed on the base substrate. The pump beam may be totally reflected once at the other end of the first waveguide, reflected from one end of the first waveguide, and incident on the first inclined side surface, and the probe beam may be totally reflected once at the other end of the second waveguide, reflected from one end of the second waveguide, and incident on the second inclined side surface.

According to one embodiment of the present invention, an atomic magnetometer comprises: a substrate including a cavity having a first inclined side surface having a first angle of inclination in a first direction and a second inclined side surface inclined at a second angle in a second direction; a lower transparent substrate disposed on a lower surface of the substrate and covering the cavity; a first mirror surface disposed on a lower portion of the lower transparent substrate and inclined at the first angle of inclination; and a second mirror surface disposed on a lower portion of the lower transparent substrate and inclined at the second angle of inclination. The first mirror surface is parallel to the first inclined side surface, the second mirror surface is parallel to the second inclined side surface, and a pump beam is incident parallel to the first direction and is reflected by the first mirror surface and the first inclined side surface of the cavity to travel in the first direction within the cavity and have a “Z” shaped beam path. The probe beam is incident parallel to the second direction, reflected from the second mirror surface and the second inclined side surface of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

An atomic magnetometer according to one embodiment of the present invention can provide a compact structure and a stable optical path.

An atomic magnetometer according to one embodiment of the present invention provides a mirror surface parallel to an inclined side surface of a cavity having a truncated pyramid structure, so that a pump beam or a probe beam incident horizontally on the mirror surface can provide a stable optical path within the cavity.

FIG. 1 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.
Figure 2 is a cross-sectional view taken along the first direction of Figure 1.
Figure 3 is a cross-sectional view taken along the second direction of Figure 1.
FIG. 4 is a cross-sectional view illustrating a method for manufacturing a cavity and vapor cell according to one embodiment of the present invention.
FIG. 5 is a cross-sectional view illustrating a lower transparent substrate and a quarter wavelength plate, a photothermal structure, and a polarizing beam splitter formed on the lower transparent substrate according to one embodiment of the present invention.
FIG. 6a is a perspective view illustrating a polarizing beam splitter formed by FIG. 5.
Fig. 6b is a perspective view illustrating the photothermal structure formed by Fig. 5.
FIG. 6c is a perspective view illustrating a quarter-wave plate formed by FIG. 5.
Fig. 7 is a cross-sectional view taken along the first direction of Fig. 1.
Fig. 8 is a cross-sectional view taken along the second direction of Fig. 11.
FIG. 9 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.
Fig. 10 is a cross-sectional view taken along the first direction of Fig. 9.
Fig. 11 is a cross-sectional view taken along the second direction of Fig. 9.
FIG. 12 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.
Fig. 13 is a cross-sectional view taken along the first direction of Fig. 12.
Fig. 14 is a cross-sectional view taken along the second direction of Fig. 12.
FIG. 15 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.
Figure 16 is a cutaway perspective view illustrating the cavity and mirror surfaces of the atomic magnetometer of Figure 15.
Fig. 17 is a cross-sectional view taken along the first direction of Fig. 15.
Fig. 18 is a cross-sectional view taken along the second direction of Fig. 15.
FIG. 19 is a cutaway perspective view illustrating the cavities and mirror surfaces of an atomic magnetometer according to one embodiment of the present invention.
Fig. 20 is a cross-sectional view taken along the first direction of Fig. 19.
Fig. 21 is a cross-sectional view taken along the second direction of Fig. 19.
FIG. 22 is a cross-sectional view taken along the first direction of an atomic magnetometer according to another embodiment of the present invention.
FIG. 23 is a cross-sectional view taken along the second direction of an atomic magnetometer according to another embodiment of the present invention.
FIG. 24 is a cross-sectional view taken along the first direction of an atomic magnetometer according to an embodiment of another embodiment of the present invention.
FIG. 25 is a cross-sectional view taken along the second direction of an atomic magnetometer according to another embodiment of the present invention.

In an atomic magnetometer, the polarization (e.g., magnetic moment) of atoms aligned in a certain direction by a pump beam changes its direction by an external magnetic field. At this time, the polarization state of the atoms can be known by measuring the degree of polarization rotation of the probe beam. In other words, the magnetic field is measured by measuring the polarization rotation angle of the probe beam. Generally, the directions of the pump beam and the probe beam are perpendicular to each other. The pump beam provides a circularly polarized beam to the alkali metal vapor cell, and the probe beam provides a linearly polarized beam to the alkali metal vapor cell.

Typically, an atomic magnetometer includes a cavity forming an alkali metal vapor cell, a heating means for heating the vapor cell, a pump light source providing a pump beam, a probe beam light source providing a probe beam, and a polarization detector for detecting rotation of the polarization of the probe beam passing through the vapor cell.

MEMS technology is used to fabricate vapor cells of atomic clocks and atomic magnetometers. In particular, when wet etching is performed to form a cavity in a silicon substrate, the silicon substrate may have a first inclination angle of 54.7 degrees. The silicon substrate may be closed by an upper transparent glass substrate and/or a lower transparent substrate to form the cavity of the vapor cell.

The pump beam or the probe beam may be reflected from the inclined side surface having a first inclination angle of 54.7 degrees and may proceed parallel to the arrangement plane of the silicon substrate within the cavity. To this end, the pump beam or the probe beam may be reflected from a mirror surface having an inclination angle of 54.7 degrees so as to proceed horizontally within the cavity and may be incident on the inclined side surface of the cavity. The 54.7 degree inclination angle of the mirror surface may be formed by wet etching of the silicon substrate. The inclined side surface of the cavity and the mirror surface may have a constant vertical distance and may be parallel to each other. Accordingly, the path of the beam may have a "Z" shape. The "Z" shaped beam path may provide a space in which another element may be arranged in the central region of the cavity. For example, a photothermal element may be arranged in the central region of the cavity. The photothermal element may be an element that receives light from the outside and converts it into heat energy. The above photothermal element can heat the alkali metal vapor cell (or cavity) to form alkali metal vapor.

According to one embodiment of the present invention, a cavity having an inclination angle of 54.7 degrees and a mirror having an inclination angle of 54.7 degrees can be manufactured using a MEMS process. Accordingly, a pump beam and a probe beam can be provided to the cavity perpendicularly to each other, thereby measuring a micromagnetic field.

According to one embodiment of the present invention, a mirror having an inclination angle of 54.7 degrees can be used by wet etching a semiconductor substrate to provide a 54.7 degree mirror surface and cutting the semiconductor substrate.

According to one embodiment of the present invention, a mirror providing a plurality of mirror surfaces can provide a mirror surface of 54.7 degrees by wet etching a semiconductor substrate. Since the cavity and the mirror have inclined surfaces of the same angle even when misaligned, a stable beam path can be provided.

According to one embodiment of the present invention, a heating means for heating a vapor cell may use a photothermal structure. When a heating light source such as a light emitting diode (LED) is incident on the photothermal structure from the outside, the photothermal structure can convert light energy into heat energy to heat the vapor cell. The photothermal structure can reduce an error caused by a magnetic field due to a current flowing in a resistive heater compared to a conventional resistive heater. In addition, the photothermal structure can provide a compact structure compared to a conventional heating air circulation structure.

According to one embodiment of the present invention, a 54.7 degree mirror surface can be implemented by one end of a flat prism having a 54.7 degree inclined surface. The other end of the flat prism has a prism structure having a 45 degree inclined angle, which can change a vertically incident beam into a parallel beam. The 54.7 degree and 45 degree beams can be formed by molding an acrylic resin plate.

An atomic magnetometer according to one embodiment of the present invention can provide a compact chip-scale atomic magnetometer using a 54.7 degree mirror.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content can be thorough and complete, and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. In the drawings, components are exaggerated for clarity. Parts denoted by the same reference numerals throughout the specification represent the same components.

FIG. 1 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.

Figure 2 is a cross-sectional view taken along the first direction of Figure 1.

Figure 3 is a cross-sectional view taken along the second direction of Figure 1.

Referring to FIGS. 1 to 3, an atomic magnetometer (100) according to one embodiment of the present invention comprises: a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclination angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclination angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclination angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

The substrate (112) is a silicon semiconductor substrate having a crystal structure, and the cavity (113) may have a truncated pyramid structure. The substrate (112) includes a cavity (113) which extends in a plane defined by a first direction and a second direction and has a first inclined side surface (112a) having a first inclination angle in a plane defined by the first direction and a third direction, and a second inclined side surface (112b) inclined at the second inclination angle in a plane defined by the second direction and the third direction. A cross-section of the cavity (113) in the first direction may have an isosceles trapezoidal shape having the first inclination angle. The first inclination angle may be 54.7 degrees. A cross-section of the cavity (113) in the second direction may have an isosceles trapezoidal shape having the second inclination angle. The second inclination angle may be 54.7 degrees.

When the substrate is a silicon semiconductor substrate, the etchant for forming the cavity (113) may be a mixture of KOH and IPA (isopropyl alcohol). The cavity (113) may have a pair of first inclined side surfaces (112a) spaced apart from each other and symmetrical along a first direction. The cavity (113) may have a pair of second inclined side surfaces (112b) spaced apart from each other and symmetrical along a second direction. The first inclined side surface (112a) and the second inclined side surface (112b) may be metal-coated or dielectric multi-coated to increase reflectivity. After forming the cavity (113), the substrate (112) may be cut into a rectangular shape by a laser or by a diamond saw.

When the cavity (113) penetrates the substrate (112), the upper transparent substrate (114) may be positioned to cover the upper surface of the cavity (113). The upper transparent substrate (114) may be a glass substrate.

The lower transparent substrate (116) may be arranged to cover the lower surface of the cavity (113). The lower transparent substrate (116) may be a glass substrate. The lower transparent substrate may cover a wide portion due to the inclined side of the cavity (113).

The above substrate (112) can be bonded to the upper transparent substrate (114) and/or the lower transparent substrate (116) using anodic bonding or an adhesive. The atomic vapor cell (110) has a sealed structure and can contain alkali metal vapor therein.

The lower transparent substrate (116) can be equipped with a quarter wavelength plate (117), a photothermal structure (118), and a polarizing beam splitter (119) on its lower surface. The lower transparent substrate (116) can function as a window for the pump beam and the probe beam to proceed into the cavity.

The quarter wave plate (117) can convert the polarization state of the pump beam of the first light source (132) from linear polarization to circular polarization and provide it to the cavity (113). The quarter wave plate (117) can be placed between the lower transparent substrate (116) and the first light source (132). Preferably, the quarter wave plate (117) is in the form of a thin film and can be placed on the lower surface of the lower transparent substrate (116).

The polarization beam splitter (119) can split the polarized probe beam that has passed through the cavity (113) according to its polarization state. The polarization beam splitter (119) can be placed between the lower transparent substrate (116) and the photodetector (154a, 154b). Preferably, the polarization beam splitter (119) is in the form of a thin film and can be placed on the lower surface of the lower transparent substrate (116).

The photothermal structure (118) may be arranged on the lower surface of the lower transparent substrate (116) or the upper surface of the upper transparent substrate (114) aligned to the central region of the cavity (113). The photothermal structure (118) may be a heating means that receives light from a heating light source (140) and converts it into heat energy by the surface plasmon resonance effect. The photothermal structure (118) may heat an alkali metal arranged inside the cavity (113) in the form of vapor. The alkali metal may be cesium (Cs) or rubidium (Rb). The cavity (113) may further include a buffer gas in addition to the alkali metal.

The heating light source (118) may be a broadband light source such as an LED. There may be a plurality of heating light sources (118). The heating light sources (118) may be placed on the base substrate (122).

The first mirror surface (126a) may be metal-coated or dielectric multi-coated to increase reflectivity. Preferably, the first inclination angle of the first mirror surface (126a) may be 54.7 degrees. The first mirror (126) may be formed by providing the first mirror surface (126a) and wet-etching a silicon semiconductor substrate. The first mirror surface (126a) and the first inclined side surface (112a) may be arranged in parallel to have a constant vertical distance. Accordingly, a horizontally incident pump beam may have an optical path of “Z”. The pump beam (12) may be incident on the first mirror surface (126a) in a first direction, reflected, and then reflected at the first inclined side surface (112a), and the pump beam (12) may proceed in parallel in the first direction within the cavity (113). The first mirror (126) may have an equilateral trapezoidal shape. The vertical height of the first mirror (126) may be the same as the height of the substrate (112). The first mirror (126) may be manufactured by wet etching a silicon semiconductor substrate.

The second mirror surface (127a) may be metal-coated or dielectric multi-coated to increase reflectivity. Preferably, the second inclination angle of the second mirror surface may be 54.7 degrees. The second mirror (127) may be formed by providing the second mirror surface and wet-etching a silicon semiconductor substrate. The second mirror surface (127a) and the second reflection side surface (112b) may be arranged in parallel to have a constant vertical distance. Accordingly, a horizontally incident probe beam may have an optical path of "Z". The probe beam (114) may be incident on the second mirror surface (127a) in the second direction, reflected, and then reflected at the second inclination side surface (112b), and the probe beam (14) may proceed in parallel in the second direction within the cavity (113). The second mirror (127) may have an equilateral trapezoidal shape. The vertical height of the second mirror (127) may be the same as the height of the substrate (112).

The base substrate (122) may be a printed circuit board, a semiconductor substrate, a transparent substrate, or a plastic substrate. The base substrate (122) may be equipped with the first mirror (126), the second mirror (127), the first light source (132), and the second light source (152). In addition, the base substrate may be a solid plate structure. The base substrate (122) may include wiring for supplying power to the first light source (132) and the second light source (152).

The first light source (132) may be a laser diode that is placed on the base substrate (122) and provides a pump beam (12) vertically. The laser diode may be a VCSEL (Vertical cavity surface emitting laser).

According to a modified embodiment of the present invention, the first light source (132) is disposed below the base substrate (122) and can provide a pump beam to the first right-angle prism (133) through a through hole.

The second light source (152) may be a laser diode that is placed on the base substrate (122) and provides a probe beam (14) vertically. The laser diode may be a VCSEL (Vertical cavity surface emitting laser).

According to a modified embodiment of the present invention, a second light source (152) is disposed below the base substrate (122) and can provide a probe beam (14) to the second right-angle prism (153) through a through hole.

The first right-angle prism (133) is arranged on the first light source (132) or the base substrate (122) and can bend the beam path of the vertically incident pump beam (12) into a right angle through one total reflection to provide a horizontal beam to the first mirror surface (126a). The pump beam (12) is reflected by the first mirror surface (126a) and provided to the first inclined side surface (112a).

The second right-angle prism (153) can be arranged on the second light source (152) or the base substrate and can bend the vertically incident probe beam (14) into a right-angled beam path through one total reflection to provide a horizontal beam to the second mirror surface (127a). The probe beam (14) is reflected by the second mirror surface (127a) and provided to the second inclined side surface (112b).

The absorber (136) can absorb the pump beam passing through the cavity (132) in the first direction. The absorber (136) can be placed on the base substrate (136).

The polarization beam splitter (119) can split the probe beam into first polarization and second polarization depending on the polarization state of the probe beam. The polarization beam splitter (119) may have a thin film structure.

The first polarization of the probe beam (14) can be detected by the first photodetector (154a) arranged below the polarization beam separator (119). The first photodetector (154a) can be arranged on the base substrate (122).

The second polarization of the probe beam (14) can be detected by a second photodetector (154b) arranged below the polarization beam separator (119). The second photodetector (154b) can be arranged on the base substrate (122).

The signal of the first photodetector (154a) and the signal of the second photodetector (154b) can be processed to provide the strength and direction of the external magnetic field.

A spacer (124) may be placed between the lower transparent substrate (116) and the base substrate (122) to maintain a certain gap. The height of the spacer (124) may be equal to or greater than the height of the first mirror (126).

According to one embodiment of the present invention, parallel pump beams and probe beams can be provided inside the cavity by using the first mirror surface and the second mirror surface. The first mirror surface (126a), the second mirror surface (127a), and the inclined side surface (112a, 112b) of the cavity can be maintained at 54.7 degrees by a silicon semiconductor wet etching process.

FIG. 4 is a cross-sectional view illustrating a method for manufacturing a cavity and vapor cell according to one embodiment of the present invention.

Referring to (a) of Fig. 4, an upper hard mask layer (211a) and a lower hard mask layer (211b) are formed on the upper surface and the lower surface of the semiconductor substrate (112), respectively. The upper hard mask layer (211a) and the lower hard mask layer (211b) may be a silicon nitride film.

Referring to (b) of Fig. 4, the upper hard mask layer (211a) is patterned. The patterning of the upper hard mask layer (211a) may include a photolithography process and an etching process.

Referring to (c) of Fig. 4, the semiconductor substrate (112) is wet-etched using the upper hard mask layer (211a) as an etching mask to expose the lower hard mask layer (211b) to form a cavity (113). The wet etching may include KOH or TMAH (tetramethylammonium hydroxide).

Referring to (d) of Fig. 4, the upper hard mask layer (211a) and the lower hard mask layer (211b) are removed by wet etching.

Referring to (e) of Fig. 4, a shadow mask (21) is placed to cover the outside of the cavity (113). Then, a reflective film (112aa) can be deposited on the inclined side (112a) of the cavity (113). The reflective film (112aa) can be a multilayer thin film composed of a metal layer or a dielectric.

Referring to (f) of Fig. 4, when the shadow mask (21) is removed, the inclined side (112a) of the cavity can have high reflectivity.

Referring to (g) of FIG. 4, an upper transparent substrate (114) is placed on a substrate (112) in which the cavity is formed, and anodic bonding is performed while a lower transparent substrate (116) is placed under the cavity (113). Accordingly, a vapor cell (110) is formed. In the step of sealing the vapor cell, an alkali metal and a buffer gas can be provided inside the cavity (113). The lower transparent substrate (116) can be equipped with a 1/4 wavelength plate (117), a photothermal structure (118), and a polarizing beam separator (119) on its lower surface.

According to the present invention, a mirror surface having a first inclination angle can be manufactured in a similar manner as described in FIG. 4.

FIG. 5 is a cross-sectional view illustrating a lower transparent substrate and a quarter wavelength plate, a photothermal structure, and a polarizing beam splitter formed on the lower transparent substrate according to one embodiment of the present invention.

FIG. 6a is a perspective view illustrating a polarizing beam splitter formed by FIG. 5.

Fig. 6b is a perspective view illustrating the photothermal structure formed by Fig. 5.

FIG. 6c is a perspective view illustrating a quarter-wave plate formed by FIG. 5.

Referring to (a) of Fig. 5, a silicon layer (86) can be deposited on a lower transparent substrate (116). The lower transparent substrate (116) can be a glass substrate.

Referring to FIG. 5(b), the silicon layer (86) may be patterned to include a plurality of regions spaced apart from each other. The silicon layer (86) may include a polarizing beam splitter region (19), a photothermal structure region (18), and a quarter wave plate region (17). Each region may have a different pattern. The polarizing beam splitter region (19) may provide a polarizing beam splitter (119). The photothermal structure region (18) may provide a photothermal structure (118). The quarter wave plate region (17) may provide a quarter wave plate (117).

The polarization beam splitter region (19) may include a plurality of columns (119a, 119d) periodically arranged in the first direction and the second direction. The polarization beam splitter region may include a plurality of columns (119a, 119d) that are regularly arranged and protrude from the lower transparent substrate. The columns (119a, 119d) may be made of a silicon material. The plurality of columns (119a, 119d) may have cross-sectional shapes having different sizes. For example, the first columns (119a) arranged in the second direction may have a rectangular cross-sectional shape having a longer side in the second direction than in the first direction. The second columns (119b) may be arranged adjacent to the first columns and may have a cross-sectional shape having a longer line in the second direction. The third columns (119c) may be arranged adjacent to the second columns and may have a cross-sectional shape having a longer line in the first direction. The fourth columns (119d) may have a rectangular cross-sectional shape with a side longer in the first direction than in the second direction. The polarizing beam splitter region may provide a polarizing beam splitter (119).

The 1/4 wavelength plate region (17) may include a plurality of columns (117a) having an elliptical cross-section that are periodically arranged. The elliptical columns may be made of silicon.

The photo-thermal structure region (18) can form a photo-thermal structure. The photo-thermal structure region can include a plurality of pillars (118a) protruding from the lower transparent substrate. The pillars (118a) can be made of a silicon material. The pillars can be arranged two-dimensionally and periodically.

Referring to (c) and (d) of FIG. 5, the photothermal structure region (18) can be opened, and the polarizing beam splitter region (19) and the quarter wave plate region (17) can be covered with a photoresist. Then, a conductive material such as gold or silver can be conformally deposited on the photothermal structure region (18). Accordingly, the pillars (118a) can have a conductive layer deposited on the side and upper surfaces as well.

Referring to (e) of FIG. 5, after removing the photoresist, the conductive layer may be heat treated to form metal nanoparticles (118b). The metal nanoparticles (118b) may provide the surface plasmon resonance effect to convert light into heat. The photothermal structure (118) may provide the surface plasmon resonance effect. The metal nanoparticles (118b) may be hemispherical.

Fig. 7 is a cross-sectional view taken along the first direction of Fig. 1.

Fig. 8 is a cross-sectional view taken along the second direction of Fig. 11.

Referring to FIGS. 7 and 8, an atomic magnetometer (100a) according to one embodiment of the present invention includes: a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclination angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclination angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclination angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

The base substrate (122) may be a printed circuit board, a semiconductor substrate, a transparent substrate, or a plastic substrate. The base substrate (122) may be equipped with the first mirror (126), the second mirror (127), the first light source (132), and the second light source (152). In addition, the base substrate may be a solid plate structure. The base substrate (122) may include wiring for supplying power to the first light source and the second light source. The base substrate (122) may have a plurality of through holes.

The first light source (132) is placed below the base substrate (122) and can provide a pump beam to the first right-angle prism (133) through a through hole (122a) penetrating the base substrate (122).

The second light source (152) is placed below the base substrate (122) and can provide a probe beam to the second right-angle prism (153) through a through hole (122b) penetrating the base substrate.

A heating light source (140) is placed below the base substrate (122) and can provide heating light to the photothermal structure (118) through a through hole penetrating the base substrate.

The first photodetector (154a) is positioned below the base substrate (122) and can detect the first polarized probe beam through a through hole penetrating the base substrate.

The second photodetector (154b) is positioned below the base substrate (122) and can detect the second polarized probe beam (14) through a through hole penetrating the base substrate.

FIG. 9 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.

Fig. 10 is a cross-sectional view taken along the first direction of Fig. 9.

Fig. 11 is a cross-sectional view taken along the second direction of Fig. 9.

Referring to FIGS. 9 to 11, an atomic magnetometer (100b) according to one embodiment of the present invention includes: a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclination angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclination angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclination angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

The first mirror surface (126a) and the second mirror surface (127a) may be formed integrally in a mirror body (128). The mirror body (128) may have a rectangular shape that is bent vertically in a plan view. The mirror body (128) may be manufactured by a MEMS process. The first mirror surface (126a) and the second mirror surface (127a) may be integrated into the mirror body (128) and may be easily aligned.

FIG. 12 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.

Fig. 13 is a cross-sectional view taken along the first direction of Fig. 12.

Fig. 14 is a cross-sectional view taken along the second direction of Fig. 12.

Referring to FIGS. 12 to 14, an atomic magnetometer (300) according to one embodiment of the present invention includes a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclination angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclination angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclination angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

The above first light source (132) is arranged on the base substrate (122) and can provide a pump beam (12) horizontal in the first direction to the first mirror surface (126a).

The second light source (152) can provide a probe beam (14) horizontal in the second direction to the second mirror surface (127a).

The first mirror surface (126a) may be metal-coated or dielectric multi-coated to increase reflectivity. The second inclination angle of the first mirror surface (126a) may be 54.7 degrees. The first mirror (326a) may be formed by providing the first mirror surface (126a) and wet-etching a silicon semiconductor substrate. The first mirror surface (126a) and the first inclination side surface (112a) of the cavity may be arranged parallel to have a constant vertical distance. Accordingly, a horizontally incident pump beam may have an optical path of "Z". The pump beam may proceed in parallel in a first direction within the cavity.

The second mirror surface (127a) may be metal-coated or dielectric multi-coated to increase reflectivity. The second inclination angle of the second mirror surface (127a) may be 54.7 degrees. The second mirror (327a) may be formed by providing the second mirror surface (127a) and wet-etching a silicon semiconductor substrate. The second mirror surface (127a) and the second inclination side surface (112b) may be arranged in parallel to have a constant vertical distance. Accordingly, a horizontally incident probe beam may have an optical path of "Z". The probe beam may proceed in parallel in the second direction within the cavity.

The third mirror surface (126b) is symmetrically arranged with respect to the first mirror surface (126a) in a first direction and can be inclined at a second angle. The third mirror (326b) can provide the third mirror surface (126b). A pump beam traveling in the first direction within the cavity can be reflected from the first inclined side surface of the cavity and then reflected by the third mirror surface (126b) to travel in the first direction. The optical path of the pump beam (12) can travel through the first mirror surface (126a), the pair of first inclined side surfaces (112a), and the third mirror surface (126b). The pump beam reflected through the third mirror surface can travel in the first direction outside the vapor cell. The pump beam reflected by the third mirror surface (126b) can be absorbed by the absorber (136).

The fourth mirror surface (127b) is symmetrically arranged with respect to the second mirror surface (127a) in the second direction and can be inclined at a second angle. The fourth mirror (327b) can provide the fourth mirror surface (127b). A probe beam traveling in the second direction within the cavity can be reflected from the second inclined side surface of the cavity and then reflected by the fourth mirror surface (127b) to travel in the second direction. The optical path of the probe beam (14) can travel horizontally in the second direction through the second mirror surface (126a), the pair of second inclined side surfaces (112b), and the fourth mirror surface (127b). The probe beam reflected through the fourth mirror surface can travel in the second direction outside the vapor cell.

The horizontal probe beam reflected by the fourth mirror surface (127b) may be provided to a polarizing beam separator (319). The polarizing beam separator (319) may be a Glan-Thomson prism. The polarizing beam separator (319) may be placed on the base substrate.

The first photodetector (154a) may be placed on one side of the polarizing beam separator.

The second photodetector (154b) may be placed on the other side of the polarizing beam separator.

According to a modified embodiment of the present invention, the first mirror surface (126a), the second mirror surface (127a), the third mirror surface (126b), and the fourth mirror surface (127b) may be formed as an integral part. Alternatively, the first mirror surface (126a), the second mirror surface (127a), and the fourth mirror surface (127b) may be formed as an integral part.

FIG. 15 is a plan view showing an atomic magnetometer according to one embodiment of the present invention.

Figure 16 is a cutaway perspective view illustrating the cavity and mirror surfaces of the atomic magnetometer of Figure 15.

Fig. 17 is a cross-sectional view taken along the first direction of Fig. 15.

Fig. 18 is a cross-sectional view taken along the second direction of Fig. 15.

Referring to FIGS. 15 to 18, an atomic magnetometer (400) according to one embodiment of the present invention includes a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclined angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclined angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclined angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

The first mirror surface (126a), the second mirror surface (127a), the third mirror surface (126b), and the fourth mirror surface (127b) may be formed integrally in a mirror body (426). The outer side of the mirror body may have a truncated pyramid structure. The mirror body may further include an opening (426a) therein. The opening (426a) of the mirror body may have an inverted truncated pyramid structure.

The first mirror surface (126a), the second mirror surface (127a), the third mirror surface (126b), and the fourth mirror surface (127b) may be formed integrally by a MEMS process and manufactured to have the same inclination angle as the inclined side surface (112a, 112b) of the cavity (113). Accordingly, the first mirror surface (112a) and the first inclined side surface (126a) may be parallel to each other. The second mirror surface (112b) and the second inclined side surface (127a) may be parallel to each other. The mirror body (426) may easily provide optical alignment with the cavity (113).

The first waveguide (428a) may be arranged on the first direction outer side of the first mirror surface (126a). The second waveguide (429a) may be arranged on the second direction outer side of the second mirror surface (127a). The third waveguide (428b) may be arranged on the first direction outer side of the third mirror surface (126b). The fourth waveguide (429b) may be arranged on the second direction outer side of the fourth mirror surface (127b). The first to fourth waveguides may be formed integrally. The first waveguide (428a) may provide optical alignment with the first light source (132). The second waveguide (429a) may provide optical alignment with the second light source (152).

One end of the first waveguide (428a) may be in contact with the first mirror surface (126a) and provide a first inclination angle. The other end of the first waveguide (428a) may be vertical. The first light source (132) may be aligned with the other end of the first waveguide to provide a pump beam (12) in a first direction.

One end of the second waveguide (429a) may be in contact with the second mirror surface (127a) and provide a second inclination angle. The other end of the second waveguide (429a) may be vertical. The second light source (152) may be aligned with the other end of the second waveguide to provide a probe beam (14) in a second direction.

One end of the third waveguide (428b) may be in contact with the third mirror surface (126b) and provide a first inclination angle. The other end of the third waveguide may be vertical. The absorber (136) may be aligned with the other end of the first waveguide and absorb the pump beam in the first direction.

One end of the fourth waveguide (429b) may be in contact with the fourth mirror surface (127b) and provide a second inclination angle. The other end of the fourth waveguide may be vertical. The polarization beam splitter (319) may receive the probe beam and branch it according to the polarization state of the probe beam.

The first photodetector (154a) is arranged on one side of the polarization beam separator (319) and can detect the probe beam (14) in the first polarization state.

The second photodetector (154b) is arranged on the other side of the polarization beam separator (319) and can detect the probe beam (14) in the second polarization state.

FIG. 19 is a cutaway perspective view illustrating the cavities and mirror surfaces of an atomic magnetometer according to one embodiment of the present invention.

Fig. 20 is a cross-sectional view taken along the first direction of Fig. 19.

Fig. 21 is a cross-sectional view taken along the second direction of Fig. 19.

Referring to FIGS. 19 to 21, an atomic magnetometer (500) according to one embodiment of the present invention includes a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclination angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclination angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclination angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

The first mirror surface (126a), the second mirror surface (127a), the third mirror surface (126b), and the fourth mirror surface (127b) may be integrally formed in a mirror body (426). The mirror body (426) may have a truncated pyramid structure, and an outer surface of the truncated pyramid may provide a mirror surface. The mirror body may further include an opening (426a) therein. The opening (426a) of the mirror body may have an inverted truncated pyramid structure.

The first mirror surface (126a), the second mirror surface (127a), the third mirror surface (126b), and the fourth mirror surface (127b) can be formed integrally by a MEMS process and manufactured to have the same inclination angle as the inclined side surface (112a, 112b) of the cavity (113). Accordingly, the first mirror surface (112a) and the first inclined side surface (126a) can be parallel to each other. The second mirror surface (112b) and the second inclined side surface (127a) can be parallel to each other. The mirror body can easily provide optical alignment with the cavity.

The first waveguide (528a) may be arranged on the first direction outer side of the first mirror surface (126a). The second waveguide (529a) may be arranged on the second direction outer side of the second mirror surface (127a). The third waveguide (528b) may be arranged on the first direction outer side of the third mirror surface (126b). The fourth waveguide (529b) may be arranged on the second direction outer side of the fourth mirror surface (127b). The first to fourth waveguides may be formed integrally. The first waveguide (528a) may provide optical alignment with the first light source (132). The second waveguide (529a) may provide optical alignment with the second light source (152). The waveguide may have a plate structure made of a transparent material.

One end of the first waveguide (528a) may be in contact with the first mirror surface (126a) and provide a first inclination angle. The other end of the first waveguide (528a) may have a right-angle prism structure and may have a 45-degree inclination. The first light source (132) may be arranged on the base substrate (122) and may provide a pump beam (12) to the inclination surface of the other end of the first waveguide (528a). The pump beam may be totally reflected at the other end of the first waveguide and may be incident on the first mirror surface in a first direction.

One end of the second waveguide (529a) may be in contact with the second mirror surface (127a) and provide a second inclination angle. The other end of the second waveguide (529a) may have a right-angle prism structure and may have a 45-degree inclination. The second light source (152) may provide a probe beam (14) to the inclination surface of the other end of the second waveguide (529a). The probe beam may be totally reflected at the other end of the second waveguide and may be incident on the second mirror surface in a second direction.

One end of the third waveguide (528b) may be in contact with the third mirror surface (126b) and provide a first inclination angle. The other end of the third waveguide (528b) may be vertical. The absorber (136) may be aligned with the other end of the first waveguide and absorb the pump beam in the first direction.

According to a modified embodiment of the present invention, the other end of the third waveguide can be transformed into a right-angle prism structure.

One end of the fourth waveguide (529b) may be in contact with the fourth mirror surface (127b) and provide a second inclination angle. The other end of the fourth waveguide may be vertical. The polarization beam splitter (319) may receive the probe beam and branch it according to the polarization state of the probe beam.

The first photodetector (154a) is arranged on one side of the polarization beam separator and can detect a probe beam in the first polarization state.

A second photodetector (154b) is arranged on the other side of the polarization beam separator and can detect a probe beam in a second polarization state.

According to a modified embodiment of the present invention, the other end of the fourth waveguide can be transformed into a right-angle prism structure.

FIG. 22 is a cross-sectional view taken along the first direction of an atomic magnetometer according to another embodiment of the present invention.

FIG. 23 is a cross-sectional view taken along the second direction of an atomic magnetometer according to another embodiment of the present invention.

Referring to FIGS. 22 and 23, an atomic magnetometer (600) according to one embodiment of the present invention includes a substrate (112) including a cavity (113) having a first inclined side surface (112a) having a first inclined angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (112) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclined angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclined angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

One end of the first waveguide (528a) may provide the first mirror surface (126a). The first inclination angle of the first mirror surface (126a) may be 54.7 degrees. The other end of the first waveguide (528a) may have a right-angle prism structure and may have an inclination of 45 degrees. The first light source (132) may be arranged on the base substrate (122) to provide a pump beam to the inclination surface of the other end of the first waveguide (528a). The pump beam may be totally reflected at the other end of the first waveguide and may be incident on the first mirror surface (126a) in the first direction. The pump beam may be totally reflected or mirror-reflected at the first mirror surface and may be incident on the first inclination side surface (112a) of the cavity (113).

One end of the second waveguide (529a) can provide the second mirror surface (127a). The second inclination angle of the second mirror surface (127a) can be 54.7 degrees. The other end of the second waveguide (529a) can have a right-angle prism structure and have an inclination of 45 degrees. The second light source (152) can provide a probe beam to the inclination surface of the other end of the second waveguide. The probe beam can be totally reflected at the other end of the second waveguide and incident on the second mirror surface in a second direction. The probe beam can be totally reflected or mirror-reflected at the second mirror surface and incident on the second inclination side surface (112b) of the cavity (113).

One end of the third waveguide (528b) may provide a third mirror surface (126b). The first inclination angle of the third mirror surface (126b) may be 54.7 degrees. The other end of the third waveguide (528b) may be vertical. The absorber (136) may be aligned with the other end of the first waveguide to absorb the pump beam in the first direction.

One end of the fourth waveguide (529b) may provide a fourth mirror surface (127b). The second inclination angle of the fourth mirror surface (127b) may be 54.7 degrees. The other end of the fourth waveguide may be vertical. The polarization beam splitter (319) may receive the probe beam and branch it according to the polarization state of the probe beam.

The first photodetector (154a) is arranged on one side of the polarization beam separator and can detect a probe beam in the first polarization state.

A second photodetector (154b) is arranged on the other side of the polarization beam separator and can detect a probe beam in a second polarization state.

The first to fourth waveguides may be manufactured as an integral part. The integral waveguide may include a waveguide cavity having a truncated pyramidal structure at its center. The inclined side of the waveguide cavity may be parallel to the cavity of the substrate. The integral waveguide may be easily optically aligned with the cavity of the substrate.

FIG. 24 is a cross-sectional view taken along the first direction of an atomic magnetometer according to an embodiment of another embodiment of the present invention.

FIG. 25 is a cross-sectional view taken along the second direction of an atomic magnetometer according to another embodiment of the present invention.

Referring to FIGS. 24 and 25, an atomic magnetometer (700) according to one embodiment of the present invention includes a substrate (712) including a cavity (113) having a first inclined side surface (112a) having a first inclination angle in a first direction and a second inclined side surface (112b) inclined at a second angle in a second direction; a lower transparent substrate (116) disposed on a lower surface of the substrate (712) and covering the cavity (113); a first mirror surface (126a) disposed on a lower portion of the lower transparent substrate and inclined at the first inclination angle; a first light source (132) disposed on a lower portion of the lower transparent substrate and providing a pump beam (12) to the first mirror surface (126a); a second mirror surface (127a) disposed on a lower portion of the lower transparent substrate and inclined at the second inclination angle; And a second light source (152) disposed below the lower transparent substrate and providing a probe beam (14) to the second mirror surface. The first mirror surface (126a) is parallel to the first inclined side surface (112a), and the second mirror surface (127a) is parallel to the second inclined side surface (112b). The pump beam (12) is incident parallel to the first direction, reflected from the first mirror surface (126a) and the first inclined side surface (112a) of the cavity, and travels in the first direction within the cavity (113) to have a “Z” shaped beam path. The probe beam (14) is incident parallel to the second direction, reflected from the second mirror surface (127a) and the second inclined side surface (112b) of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.

In the above substrate (712), the cavity (13) may leave an upper surface without penetrating the substrate (712). Accordingly, the vapor cell (110) may include a lower transparent substrate (116) covering the lower surface of the substrate (712) and the cavity (113). The first inclination angle and the second inclination angle of the cavity (113) may be 54.7 degrees.

Although the present invention has been illustrated and described with respect to certain preferred embodiments, the present invention is not limited to these embodiments, but includes various forms of embodiments that can be implemented by a person skilled in the art without departing from the technical idea of the present invention claimed in the claims.

100: Atomic magnetic field
112: Substrate
116: Lower transparent substrate
126a: First mirror surface
127a: Second mirror surface

Claims (21)

A substrate comprising a cavity having a first inclined side surface having a first inclined angle in a first direction and a second inclined side surface having a second inclined angle in a second direction;
A lower transparent substrate disposed on the lower surface of the substrate and covering the cavity;
A first mirror surface disposed on the lower portion of the lower transparent substrate and inclined at the first inclination angle;
A first light source disposed below the lower transparent substrate and providing a pump beam to the first mirror surface;
A second mirror surface disposed on the lower portion of the lower transparent substrate and inclined at the second angle; and
A second light source is disposed below the lower transparent substrate and provides a probe beam to the second mirror surface;
The first mirror surface is parallel to the first inclined side surface, and the second mirror surface is parallel to the second inclined side surface.
The pump beam is incident parallel to the first direction, reflected from the first mirror surface and the first inclined side surface of the cavity, and travels in the first direction within the cavity to have a beam path in the shape of a “Z”.
The probe beam is incident parallel to the second direction, reflected from the second mirror surface and the second inclined side surface of the cavity, and travels in the second direction within the cavity to have a beam path in the shape of a “Z”.
An atomic magnetometer, wherein the cavity provides a vapor cell, and the second direction is characterized in that it is perpendicular to the first direction. In the first paragraph,
The above substrate is a silicon substrate,
An atomic magnetometer, characterized in that the first inclination angle and the second inclination angle are 54.7 degrees. In the first paragraph,
An atomic magnetometer further comprising an upper transparent substrate disposed on an upper surface of the substrate and covering the cavity. In the first paragraph,
A first mirror made of silicone and providing the first mirror surface;
a second mirror made of silicone and providing the second mirror surface; and
An atomic magnetometer further comprising a base substrate on which the first mirror and the second mirror are arranged. In the fourth paragraph,
a first right-angled prism disposed on the first light source; and
Further comprising a second right-angled prism disposed on the second light source,
The first light source is placed on the base substrate,
The second light source is placed on the base substrate,
The above pump beam is totally reflected once by the first right-angle prism and is incident in the first direction parallel to the first mirror surface,
An atomic magnetometer, characterized in that the probe beam is totally reflected once by the second right-angle prism and is incident in a second direction parallel to the second mirror surface. In the first paragraph,
A photo-thermal structure disposed on the lower portion of the lower transparent substrate; and
An atomic magnetometer further comprising a heating light source that irradiates light to the photothermal structure. In Article 6,
An atomic magnetometer characterized in that the above photo-thermal structure has a surface plasmon resonance structure. In Article 7,
The above photo-thermal structure:
A plurality of pillars protruding from the lower transparent substrate;
Comprising metal nano particles formed on the upper and side surfaces of the pillars and on the lower transparent substrate between the pillars,
An atomic magnetometer characterized in that the above metal nanoparticles are hemispherical. In the first paragraph,
Further comprising a first 1/4 wavelength plate disposed on the lower transparent substrate;
An atomic magnetometer, characterized in that the first 1/4 wave plate is arranged on the optical path of the pump beam. In Article 9,
The above first 1/4 wave plate
A plurality of elliptical pillars protruding from the lower transparent substrate and arranged at regular intervals;
An atomic magnetometer characterized in that the above elliptical columns are made of silicon. In the first paragraph,
A polarizing beam splitter arranged on the lower transparent substrate; and
Further comprising a first photodetector and a second photodetector arranged below the polarizing beam separator,
An atomic magnetometer, characterized in that the polarization beam splitter splits the probe beam traveling in the second direction according to the polarization state and provides the split beam to the first photodetector and the second photodetector, respectively. In Article 11,
The above polarizing beam splitter
A plurality of pillars regularly arranged and protruding from the lower transparent substrate;
An atomic magnetometer characterized in that the multiple pillars are made of silicon with cross-sectional shapes of different sizes. In the first paragraph,
A base substrate on which a first mirror providing the first mirror surface and a second mirror providing the second mirror surface are arranged; and
An atomic magnetometer further characterized by comprising a spacer disposed between the base substrate and the lower transparent substrate. In the first paragraph,
A base substrate on which a first mirror providing the first mirror surface and a second mirror providing the second mirror surface are arranged;
a third mirror disposed on the base substrate and providing a third mirror surface inclined at the first inclination angle; and
Further comprising a fourth mirror disposed on the base substrate and providing a fourth mirror surface inclined at the second inclination angle;
The optical path of the above pump beam proceeds through the first mirror surface, a pair of first inclined sides, and a third mirror surface,
An atomic magnetometer, characterized in that the optical path of the probe beam proceeds through the second mirror surface, a pair of second inclined side surfaces, and the fourth mirror surface. In Article 14,
A polarizing beam splitter provided with a probe beam reflected from the fourth mirror surface and arranged on the base substrate;
a first photodetector arranged on one side of the polarizing beam separator; and
An atomic magnetometer, characterized in that it further comprises a second photodetector arranged on the other side of the polarizing beam separator. In the first paragraph,
A base substrate on which a first mirror providing the first mirror surface and a second mirror providing the second mirror surface are arranged;
A first waveguide continuously connected to the first mirror surface and arranged on the base substrate; and
Further comprising a second waveguide continuously connected to the second mirror surface and arranged on the base substrate;
The above pump beam is incident on the first waveguide, reflected on the first mirror surface, and incident on the first inclined side surface,
An atomic magnetometer, characterized in that the probe beam is incident on the second waveguide, reflected by the second mirror surface, and incident on the second inclined side surface. In Article 16,
A third mirror disposed on the base substrate and providing a third mirror surface inclined at the first inclination angle;
A fourth mirror disposed on the base substrate and providing a fourth mirror surface inclined at the second inclination angle;
a third waveguide continuously connected to the third mirror surface; and
Further comprising a fourth waveguide continuously connected to the fourth mirror surface;
The optical path of the above pump beam proceeds through the first waveguide, the first mirror surface, a pair of first inclined sides, a third mirror surface, and the third waveguide,
An atomic magnetometer, characterized in that the optical path of the probe beam proceeds through a second waveguide, the second mirror surface, a pair of second inclined side surfaces, the fourth mirror surface, and the fourth waveguide. In Article 16,
One end of the above first waveguide is a prism structure with a 45 degree inclined structure,
The above first light source is placed on the base substrate,
The above pump beam is totally reflected once in the prism structure of the first waveguide and proceeds to the first mirror surface,
One end of the above second waveguide is a prism structure with a 45 degree inclined structure,
The second light source is placed on the base substrate,
An atomic magnetometer, characterized in that the probe beam is totally reflected once in the prism structure of the second waveguide and proceeds to the second mirror surface. In the first paragraph,
A first waveguide including the first mirror surface and arranged on a base substrate; and
Further comprising a second waveguide including the second mirror surface and arranged on the base substrate;
The above pump beam is incident on the first waveguide, reflected on the first mirror surface, and incident on the first inclined side surface,
An atomic magnetometer, characterized in that the probe beam is incident on the second waveguide, reflected by the second mirror surface, and incident on the second inclined side surface. In Article 19,
The other end of the above first waveguide has a right-angle prism structure,
The other end of the above second waveguide has a right-angle prism structure,
The first light source is placed on the base substrate,
The second light source is placed on the base substrate,
The above pump beam is totally reflected once at the other end of the first waveguide, reflected at one end of the first waveguide, and incident on the first inclined side surface,
An atomic magnetometer, characterized in that the probe beam is totally reflected once at the other end of the second waveguide, reflected at one end of the second waveguide, and incident on the second inclined side surface. A substrate comprising a cavity having a first inclined side surface having a first inclined angle in a first direction and a second inclined side surface having a second inclined angle in a second direction;
A lower transparent substrate disposed on the lower surface of the substrate and covering the cavity;
A first mirror surface disposed on the lower portion of the lower transparent substrate and inclined at the first inclination angle; and
A second mirror surface disposed on the lower side of the lower transparent substrate and inclined at the second angle;
The first mirror surface is parallel to the first inclined side surface, and the second mirror surface is parallel to the second inclined side surface.
The pump beam is incident parallel to the first direction, reflected from the first mirror surface and the first inclined side surface of the cavity, and travels in the first direction within the cavity to have a beam path in the shape of a “Z”.
The probe beam is incident parallel to the second direction, reflected from the second mirror surface and the second inclined side surface of the cavity, and travels in the second direction within the cavity to have a “Z” shaped beam path.
An atomic magnetometer, wherein the cavity provides a vapor cell, and the second direction is characterized in that it is perpendicular to the first direction.

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