WO2007010951A1 - Cavity ringdown spectroscopy method and probe using it - Google Patents

Abstract

Cavity ringdown spectroscopy for analyzing a specimen deposited on a cavity outer wall surface. (Fig. 1.A) Mirrors (21, 22) are provided on the side surface, including the long side of the bottom surface, of a triangle pole prism (13) having a rectangular equilateral triangle-shaped bottom surface. A detection light incident from an optical fiber or the like (11) is supplied to the prism (13) via the mirror (21). The detection light is ringed-down at four reflection planes, two planes, including the respective two short sides of the bottom surface, of the prism (13) and the mirrors (21, 22). When a matter to be measured is deposited on probe's outer wall surfaces which are reflection planes including the respective two short sides of the bottom surface, of the prism (13), a ringdown factor is increased by the absorption of an evanescent wave or a near-field light. Accordingly, a time constant is determined from a change in the intensity of an output light from a mirror (12) to be able to calculate an absorption coefficient. The constitutions in 1.B-1.D are also possible. The sign 25 in 1.C denotes a piezoelectric element that forms a continuous light (CW) into a pulse shape, and the sign 14 in 1.D denotes isosceles trapezoidal prism.

Description

 Specification

 Cavity ring-down spectroscopy method and probe used therefor

 Technical field

 The present invention relates to a cavity ring-down spectroscopy method using absorption of an evanescent wave or near-field light of a substance attached to the tip of a probe, and a probe used therefor. Background art

 As is well known, in cavity ring-down spectroscopy, “cavity” is formed by at least two mirrors, and a test substance (sample) is introduced into the “cavity”. This is a spectroscopic analysis of the ring-down light of the sample in the cavity. In the cavity ring-down spectroscopy, the absorption coefficient at each wavelength of the sample is obtained by measuring the time constant of attenuation of light intensity mainly due to light absorption, and identification and quantification are performed. Patent Document 1: Japanese Unexamined Patent Publication No. 2000-338037

 Patent Document 2: Japanese Patent Laid-Open No. 2001-194299

 Patent Document 3: Japanese Patent Application Laid-Open No. 2004-333337

 Disclosure of the invention

 Problems to be solved by the invention

[0003] The inventors of the present invention have studied a method for applying the cavity ring-down spectroscopy under such a condition that the sample cannot be introduced into the “cavity”. Here, it was confirmed as follows that ring-down occurs due to absorption of evanescent waves or near-field light, and a completely new invention of the present invention was completed.

 Means for solving the problem

[0004] The invention according to claim 1 is a probe used for cavity ring-down spectroscopy, and includes a first mirror and a second mirror that reflect light, and at least two total reflection or high reflection surfaces. A first mirror and a second mirror are formed, and a cavity that forms an optical path for reflecting the detection light between the two mirrors through a total reflection or a high reflection surface and an arbitrary number of times is connected to the first mirror. The first optical waveguide that allows the detection light to enter the cavity through the first mirror, and the second mirror that is connected to the second mirror and transmits the second mirror to output a part of the cavity detection light. An evanescent wave or near-field light that oozes from the total reflection or high reflection surface by attaching an object whose absorption coefficient is to be measured to the outer surface of at least one of the total reflection or high reflection surface. It is a probe for cavity ring-down spectroscopy characterized by detecting absorption.

 As the optical waveguide, an optical fiber, a rod made of force such as quartz glass and germanium can be used. These optical waveguides should be protected by being inserted into a tube made of stainless steel or the like. A cavity is preferably connected to the tip of the tube. For the cavity, a prism with a right-angled triangle section or a prism with a trapezoidal section can be used.

 [0005] The invention according to claim 2 is a probe used for cavity ring-down spectroscopy, and is continuous with the first optical waveguide, the second optical waveguide, and the tip end portions of the first optical waveguide and the second optical waveguide. A reflector having at least two total reflection or high reflection surfaces, a first mirror formed on the light incident end surface of the first optical waveguide, and a second mirror formed on the light emitting end surface of the second optical waveguide. The first mirror, the first optical waveguide, the reflector, the second optical waveguide, and the second mirror transmit the detection light between these two mirrors via a total reflection or highly reflective surface. An evanescent wave or near field that exudes from the total reflection or high reflection surface is formed by attaching an object whose absorption coefficient is measured to the outer surface of at least one of the total reflection or high reflection surface. A cavity ring characterized by detecting the absorption of light A probe down spectroscopy.

 Also in this invention, the configuration of the optical waveguide and the cavity is the same as that of the invention of claim 1, and an optical light guide may be inserted into a tubular body such as stainless steel, or a cavity may be provided at the distal end of the tubular body. This is the same as the invention of claim 1.

[0006] The invention according to claim 3 is a probe used for cavity ring-down spectroscopy, and is formed of an optical waveguide and at least one aperture formed at one end of the optical waveguide and having a width equal to or smaller than the wavelength of the detection light. A first total reflection or high reflection mirror formed, and a second mirror formed at the other end of the optical waveguide, the first total reflection or high reflection mirror, the optical waveguide, and the second mirror. A cavity that reflects the detection light arbitrarily between these two mirrors is formed, and an object whose absorption coefficient is to be measured is attached to the outer surface of the first total reflection or high reflection mirror. Is a cavity ring-down spectroscopic probe characterized by detecting the absorption of near-field light that oozes out the power of a highly reflective mirror.

 Also in the present invention, the optical waveguide can be an optical fino, a rod made of quartz glass, germanium, or the like. These optical waveguides may be inserted into a tube having an opening having a diameter smaller than that of the main body at both end faces such as stainless steel so as to protect the optical waveguide. Desirably, each end face of the optical waveguide is exposed to the opening of each end face of the tube.

[0007] The invention according to claim 4 is the cavity ring-down spectroscopic probe according to claim 1 or claim 2, wherein the object for measuring the absorption coefficient is attached to the surface of the total reflection or high reflection surface. Is formed with a total reflection or high reflection layer in which at least one aperture having a width equal to or smaller than the wavelength of the detection light is formed, and detects the absorption of near-field light that has penetrated the total reflection or high reflection layer force. It is characterized by that.

 The invention according to claim 5 is the cavity ring-down spectroscopic probe according to claim 3, wherein the first total reflection or high reflection mirror is not more than the wavelength of the detection light in the form of a lattice formed on the reflecting member. It has the opening which has the width | variety.

 The invention according to claim 6 is the cavity ring-down spectroscopy probe according to claim 4, wherein the total reflection or high reflection layer has a lattice-like width formed on the reflecting member and having a width equal to or less than the wavelength of the detection light. It has the opening which has.

 Further, the invention according to claim 7 is the method according to any one of claims 1 to 6, wherein the detection light is supercontinuum laser light or soliton pulse laser light. It is femtosecond laser light.

[0008] The invention according to claim 8 is a cavity ring-down spectroscopy method, wherein the detection light is totally reflected or highly reflected on an outer wall surface to which the object of the cavity is attached, and has a width equal to or smaller than the wavelength of the detection light. A cavity ring-down spectroscopic method characterized in that a total reflection or high reflection layer having at least one aperture is provided, and absorption of near-field light oozing out from the total reflection or high reflection layer is detected by an object. is there.

The invention according to claim 9 is the cavity ring-down spectroscopic method according to claim 8, wherein the total reflection or high reflection layer has a grating-like shape formed on the reflecting member and has a wavelength equal to or less than the wavelength of the detection light. It has the opening which has the width | variety of this, It is characterized by the above-mentioned.

 Further, the invention according to claim 10 is that the periodic pulse light by the femtosecond laser, the super continuum light, or the soliton pulse light is split into the measurement light and the reference light, and the measurement light is claimed in claim 1. The light input from the second optical waveguide of the probe is input to the first optical waveguide of the probe according to any one of claims 7 to 7, and the reference light is incident on a transmission path whose length varies periodically. This is a cavity ring-down spectroscopic method characterized by detecting absorption by an object by interfering with the reference light propagated through the transmission path and performing homodyne detection.

 The invention's effect

 [0009] As described below, the inventors of the present application have found that the absorption of an evanescent wave or near-field light of a substance attached to the cavity outer wall surface can be detected. This is a completely different configuration from the conventional cavity ring-down spectroscopy, which is based on the premise that a sample is introduced into the cavity. As a result, even if it is difficult to introduce the sample into the cavity, if the substance to be inspected can be attached to the probe surface, the identification of the substance to be inspected by cavity ring-down spectroscopy or Quantification is possible. In the case of a configuration using a near field, the near field does not propagate even if the refractive index of the sample is larger than the refractive index of the cavity to which the sample is attached or the optical waveguide. Is possible. Specifically, according to the configuration of claims 1 to 7, it can be easily configured.

[0010] In addition, a configuration in which homodyne detection is performed on the output light and the reference light introduced into the probe using periodic pulsed light having a short pulse width is also useful. At this time, if the optical path length on the reference light side is periodically changed, the detection output changes with the optical path length coincident. Furthermore, if the optical path length on the reference side is made longer while periodically obtaining a detection output, homodyne detection output between the ringdown output light and the reference light and two ringdown output lights are obtained. And reference light homodyne detection output, and so on, output can be obtained, so even when a ring with a very short ring-down interval, that is, with a very short cavity length, is used as a probe, A decrease in output can be detected.

 Brief Description of Drawings

[0011] [Fig. 1] Four specific configurations of a cavity ring-down spectroscopic probe according to the present invention. FIG. 2 shows two other specific configurations of the probe for the cavity ring-down spectroscopy according to the present invention.

 FIG. 3 is a diagram showing two configurations of the cavity ring-down spectroscopy probe according to the present invention.

[4] Configuration diagram of a plasma generating apparatus using the cavity ring-down spectroscopy probe according to the present invention.

圆 5] A graph showing experimental results in Example 1.

6] A graph showing the action of the piezoelectric element in Example 2.

 [Fig. 7.A] Graph showing first measurement data by FT-IR-ATR.

 FIG. 7.B is a graph showing second measurement data by FT-IR-ATR.

 [Fig. 7.C] Graph showing third measurement data by FT-IR-ATR.

 FIG. 8 is a block diagram of a probe for cavity ring-down spectroscopy in Example 3.

9] A graph showing experimental results in Example 3.

 FIG. 10 is a graph showing temperature change of UV absorption of DNA.

 FIG. 11 shows two other specific configurations of the cavity ring-down spectroscopy probe according to the present invention.

 FIG. 12 is a detailed block diagram of the cavity in the fifth embodiment.

FIG. 13 shows two configuration diagrams of the cavity surface in Example 5.

14] Overall configuration diagram of measurement system in Example 5.

FIG. 15 is a graph showing experimental results in Example 5.

 FIG. 16.A is a timing chart showing the relationship between ring-down pulse light and reference light in homodyne detection in an application example of Example 5.

 [Fig. 16.B] Timing chart showing the interference relationship between pulsed light and reference light in this application example.

 [FIG. 16.C] A timing chart showing an interference pulse in the same application example.

[16D] Timing chart showing the relationship between the interference pulse and mirror vibration period in this application example.

[Fig. 16.E] Timing chart showing the relationship between each ring-down pulse and interference pulse in this application example. Explanation of symbols

 [0012] 10: Quartz rod

 11, 12: Probe body such as optical fiber

 13: Triangular prism with a right isosceles triangle base

 1310, 170: Metal film with micropores

 14: Prism with isosceles trapezoidal bottom

 15: Spherical cavity

 150: Light extraction part

 16: Cylindrical cavity

 17: Polygonal column cavity

 110, 120, 20, 21, 22: Mirror

 23: Mirror with micropores

 25: Piezoelectric element

 30: Tunable pulse laser

 31: Tunable CW laser

 35: QCW laser

 36: Femtosecond laser beam generator

 40: Receiver

 50: Beam splitter

 51: Pockels cell (wavelength variable Z4 plate)

 60: Heater and temperature sensor

 70: Probe stand with silicon substrate power

 80: Movable mirror

 BEST MODE FOR CARRYING OUT THE INVENTION

First, a configuration example of a cavity ring-down spectroscopy probe according to the present invention will be described with reference to the drawings. The cavity ring-down spectroscopy probe according to the present invention is not limited to the specific examples described below. “Miraichi” for forming the cavity preferably has a reflectance of 99.5% or more and a transmittance of 0.5% or less. More preferably, the transmittance is 8% or more and the transmittance is 0.2% or less. Of course, the mirror may have some absorption. Other optical elements and optical equipment can be selected arbitrarily, and unless otherwise specified, it is not necessary to use high-quality optical elements.

 FIG. 1 shows a specific configuration example of the present invention using two mirrors, a probe main body made of an optical fiber or the like, and a prism. In FIG. 1, the optical path is indicated by an arrow.

 FIG. 1. A is a configuration diagram of the probe 101 for cavity ring-down spectroscopy. Two mirrors 21 and 22 are provided on the side corresponding to the long side of the bottom of the triangular prism prism 13 whose bottom is a right isosceles triangle, and the two optical fibers 11 and 12 constituting the optical waveguide are two. It is joined to mirrors 21 and 22. The mirrors 21 and 22 can be made of a metal, a dielectric multilayer film, or the like having a high reflectivity with respect to the wavelength of light used for measurement, such as aluminum, silver, and rhodium. The transmittance can be adjusted by the thickness of the entire film or the number of layers of the dielectric multilayer film. The two side surfaces 131 and 132 corresponding to the short side of the bottom surface of the triangular prism 13 and the two mirrors 21 and 22 form a cavity in which the detection light reciprocates. Further, when a substance adheres to the two side surfaces 131 and 132 of the triangular prism prism 13, it can be detected that the ringdown rate of the detection light increases due to absorption of the evanescent wave of the detection light. When detecting the absorption of near-field light, the side surfaces 131 and 132 to which the substance is attached (if one is attached only to one side, only one of them) have a minute size that is smaller than the wavelength of the light used for the measurement. A mirror having an opening is formed. For example, it can be formed by vapor-depositing a metal or a dielectric multilayer film having a high reflectivity with respect to the wavelength of light used for measurement. The micro openings may be a single circle, a large number of irregularly arranged holes, or a circularly regularly arranged circle. Further, a one-dimensional diffraction grating in which slits are arranged in a one-dimensional direction and a two-dimensional diffraction grating in which rectangular openings are arranged in a lattice shape may be used. The detection light to be introduced into such a cavity ring-down spectroscopic probe 101 is preferably the output of the wavelength tunable pulse laser 30. It is also detected by the light receiver 40. As the optical waveguide, a quartz glass rod may be used in place of the optical fibers 11 and 12. FIG. 1. A cavity ring-down spectroscopic probe 101 of A corresponds to a specific embodiment of the invention of claim 1.

FIG. 1. B is a block diagram of the cavity ring-down spectroscopic probe 102. Direct bottom Join one end of two optical fibers 11 and 12 to the side 133 of the triangular prism prism 13 that is an isosceles triangle and correspond to the long side of the bottom, and two mirrors 21 and 22 to the other end It is a thing. A “cavity” in which detection light reciprocates is formed by the two side surfaces 131 and 132 corresponding to the short side of the bottom surface of the triangular prism 13 and the two mirrors 21 and 22. Figure 1. The cavity ring-down spectroscopy probe 102 in B has a longer reciprocating optical path than the cavity ring-down spectroscopy probe 101 in Figure 1. A. Fig. 1. The cavity ring-down spectroscopy probe 102 in B is similar to the cavity ring-down spectroscopy probe 101 in Fig. 1. A. Two probes corresponding to the short side of the bottom surface of the triangular prism 13 are provided. When a substance adheres to the side surfaces 131 and 132, it can be detected that the ringdown rate of the detection light increases due to absorption of the evanescent wave of the detection light. When detecting near-field light absorption, a small aperture with dimensions smaller than the wavelength of the light used for the measurement is provided on the side surfaces 131 and 132 to which the substance is attached (if it is attached only to the side). A mirror provided with is formed. For example, it can be formed by vapor-depositing a metal having a high reflectance with respect to the wavelength of light used for measurement. FIG. 1. The cavity ring-down spectroscopic probe 102 of B corresponds to a specific embodiment of the invention according to claim 2. Also in this embodiment, as in the embodiment of FIG. 1.A, a quartz glass rod may be used for the optical waveguide instead of the optical fiber. The same applies to the configuration of the minute aperture in the case of using near-field absorption.

 FIG. 1. C is a configuration diagram of the cavity ring-down spectroscopic probe 103. Figure 1. C cavity ring-down spectroscopic probe 103 is the configuration of cavity ring-down spectroscopic probe 102 in Figure 1. B, with a piezoelectric element 25 on mirror 21 and is used as a detection light generator. A tunable continuous light (CW) laser 31 is applicable. The transmittance of the mirror 21 is changed by the piezoelectric element 25, and the CW light of the wavelength tunable CW laser 31 can be pulsed and introduced into the cavity (in the probe).

FIG. 1. D is a configuration diagram of the cavity ring-down spectroscopic probe 104. Fig. 1. The cavity ring-down spectroscopic probe 104 in D is composed of a prismatic prism 13 whose bottom surface is a right isosceles triangle in the configuration of the cavity ring-down spectroscopic probe 102 in Fig. 1. B. It is replaced with a horizontally long isosceles trapezoidal prism 14. In addition, two optical fibers 11 and 12 are arranged in parallel with each other in accordance with the horizontally long prism 14. is doing. Fig. 1. The cavity ring-down probe 104 of D has side surfaces 141 and 142 corresponding to the sides of the bottom surface of the isosceles trapezoidal prism 14 with a horizontally long bottom surface, and a side surface corresponding to the bottom surface of the bottom surface 143 And the side surface 144 corresponding to the lower base are reflected several times to detect the absorption of the evanescent wave on the outer wall surface of the probe. When detecting the absorption of near-field light, a mirror with a microhole is used.

FIG. 2 shows the detection of near-field light absorption using a mirror 23 provided with a minute hole and a single optical fiber. Here, the microhole means a hole having a diameter of about the wavelength of the detection light or less, preferably a hole having a diameter of about 1Z2 or less of the detection light. The mirror 23 having such a minute hole can be formed by attaching metal or the like to the end face of the optical fiber or the like forming the cavity and then removing the metal in the hole portion by micromachining. When infrared light having a wavelength of about 1 to 50 m is used as detection light, it is not difficult to form such micropores.

 FIG. 2. A is a configuration diagram showing the configuration of the probe 201. The probe 201 is provided with a mirror 21 at one end of an optical fiber 11 and the like, and a mirror 23 with a microhole formed at the other end, and a cavity is formed between the mirror 21 and the mirror 23. When a substance adheres to the micropores of the mirror 23, absorption or absorption of near-field light occurs, and the substance can be identified or quantified by cavity ring-down spectroscopy. In Fig. 2. A, the measurement system is configured to generate P-polarized light from the wavelength-tunable pulse laser 30 and provide the beam splitter 50 and 1Z4 wavelength-tunable Pockels cell to receive the S-polarized light by the light receiver 40. Figure 2. A cavity ring-down spectroscopic probe 201 in A corresponds to a specific embodiment of the invention according to claim 3.

FIG. 2. B is a configuration diagram showing the configuration of the probe 202. Figure 2. Probe ring 202 for cavity ring-down spectroscopy is the configuration of probe 201 for cavity ring-down spectrum in figure 2. A mirror 21 is provided with a piezoelectric element 25, and the wavelength of the detection light generator is variable. A continuous light (CW) laser 31 is applicable. The transmittance of the mirror 21 is changed by the piezoelectric element 25, and the CW light of the wavelength tunable CW laser 31 can be pulsed and introduced into the cavity (in the probe). In Fig. 2.B, as the measurement system, P-polarized light is generated from the tunable pulse laser 31 and the beam splitter 50 and 1Z4 tunable Pockels cell are installed. A configuration in which the optical device 40 receives S-polarized light is shown.

 FIG. 3 shows a difference in configuration between the case where the absorption of the evanescent wave is detected and the case where the absorption of the near-field light is detected. Figure 3. A shows a configuration similar to that of Figure 1. A. Here, the case where a sample (sample) is directly attached to the side surface 131 of the prismatic prism 13 whose bottom surface is a right-angled isosceles triangle is shown in FIG. Figure 3.C shows the case of forming and attaching a sample to the micropore.

 [0023] Fig. 3. B is a sample having a refractive index lower than the refractive index of the prism 13 having a triangular prism shape.

 Suitable for detecting (sample). If a sample having a refractive index higher than the refractive index of the triangular prism 13 is attached, the attached part will be! In the end, total reflection of the detected light cannot be expected. That is, as shown in FIG. 3.B, the detection light that is incident on the internal upper force side surface 131 of the prism-shaped prism 13 and is to be reflected to the right is a sample having a high refractive index. And leaks downward in the figure, outside the prism 13. In this state, absorption of the evanescent wave by the sample cannot be detected.

 [0024] When a sample having a refractive index higher than that of the triangular prism 13 is to be detected, a micropore is formed on the side surface 131 of the triangular prism 13 as shown in Fig. 3. C. A metal film 1310 is formed, and a sample is preferably attached to the micropore. The diameter of the microhole is made smaller than the wavelength of the detection light. In this case, only the near-field light acts on the sample having a high refractive index in the microhole, so that downward detection light leakage as shown in Fig. 3.B does not occur. In other words, this configuration makes it possible to detect absorption of near-field light.

[0025] The metal film 1310 having micropores is preferably formed, for example, by vapor deposition of silver. In addition, it is better to form a large number of small terms, one by one. When the absorption of near-field light is detected by forming a metal film 1310 having micropores with silver or the like, the sensitivity is equal to or higher than that when detecting absorption of evanescent waves even if the aperture ratio is small. This is thought to be because the absorption sensitivity is enhanced several tens of times or more by the local surface plasmon effect of silver or the like. Examples of metals that exhibit the local surface plasmon effect include silver, gold, tungsten, and the like. The shape of the microscopic aperture may be a circle, a square, a rectangle, etc. In this case, a stripe shape may be used. That is, near-field light can be generated by a slit perpendicular to the polarization direction of light, that is, a stripe-shaped slit having a narrow width in the polarization direction of light, and evanescent waves can be prevented from being generated. As described above, the evanescent wave mainly uses total reflection using an incident angle larger than the critical angle, but uses near the near-field light, a microhole or slit of a high reflection mirror.

 Example 1

 A probe 103 or 104 was installed near the side wall of the chamber 1100 of the plasma apparatus 1000 having the configuration shown in FIG. The plasma device 1000 in Fig. 4 uses 2.45GHz, 400W microwave and 2MHz high frequency, and electron cyclotron from SiH, H, CF and other source gases.

 4 2 4 8

 Plasma is generated by resonance. A substrate 900 to be processed is placed in the center of the cylindrical chamber 1100, and a probe is placed on the side wall surface of the chamber 1100.

In this example, a probe 104 having the shape shown in FIG. A quartz prism was used as the prism 14 having an isosceles trapezoidal bottom, and quartz rods 11 and 12 were used as the optical waveguide. An oscillating dye (Dye) laser excited by an Nd: YAG laser was used as the wavelength tunable pulse laser. The size of the prism 14 with the isosceles trapezoidal shape is the same as that of the isosceles trapezoid that is the bottom. The length of the upper base is 25 mm, the bottom is 30 mm, the side is about 6 mm ) 5 mm was used.

 [0028] After introducing SH into the chamber 1100 and plasmaizing it for 1 second, the probe quartz pre-

 Four

 The absorption coefficient of the film-like substance formed on the optical surface, that is, the reflection surface reflecting the optical path, was also determined as the change in the time constant of the light intensity attenuation. At this time, the photon energy was swept to 1 to 2.2 eV (approximately 8000 to 17700 cm. This result is shown by (a) in the graph of FIG. 5. Next, a mixed gas of H and SH in the chamber 1100 ( (SH concentration 20%) and plasma for 1 second

 2 4 4

 Turned into. In this case, the absorption coefficient of the film-like substance formed on the surface of the quartz prism of the probe is shown by (b) in the graph of FIG. From these two graphs (a) and (b), the SH concentration is 100.

 Four

 Compared with%, when SH concentration in H is 20%, photon energy is leV ~: L 4e

 twenty four

 The absorption coefficient decreases in the range of V! /

 This is the structure of the amorphous silicon film that is formed when the SH concentration is not 100%.

 Four

Since the fact that defects are involved is divided, Figure 5 (a) and (b) reflect this. It is thought that there is. As a result, the invention of the present application is formed by SH plasma.

 Four

 This shows that it can be expected as a sensor probe for controlling the film quality distribution of rufus silicon film and the plasma state.

 Example 2

 A probe was installed near the side wall of the chamber 1100 of the plasma apparatus 1000 having the configuration shown in FIG. In this example, the probe 103 in FIG. A germanium prism was used as the prism 13 whose bottom surface is a right isosceles triangle, and germanium rods were used as the optical fibers 11 and 12. As for the size of the prism 13 whose bottom surface is a right isosceles triangle shape, a prism with a short side length of 10 mm and a prism height (thickness) of 10 mm was used.

[0030] The detection light is configured such that the light emitted from the tungsten lamp is introduced by a ZnSe lens through a polycrystalline silver nitride fiber. In addition, the piezoelectric element 25 introduced “pulsed” detection light into the cavity. A spectroscope (MCT) was attached to the receiver. Fig. 6 shows how the continuous light can be pulsed by the piezoelectric element 25. At this time, the wave number was 1900 cm ¹ and the decay time constant due to ringdown was 2 s.

[0031] After introducing SH into the chamber and turning it into plasma for 1 second, wave number 1900cm— ¹ to 2300c

 Four

spectral in 10Cm- ¹ increments until m ^_1 was determined by large-area FT-IR-ATR. The results are shown in Figure 7.A. Figure 7. A shows the change in absorbance with wave number. In the apparatus of the present embodiment, a high-reflectance mirror can be realized in this entire wavelength band, and the same measurement can be performed if the output of the light source can be increased in this wavelength band. The change in absorbance is proportional to the time constant shortening time in the cavity ring-down spectroscopy, and the time constant shortening is caused by the infrared absorption of the film attached to the prism 13. Fig. 7. As shown in Fig. A, absorption due to stretching vibration of SiH at 2100 cm ¹ and SiH at 2000 cm ¹ can be observed.

2

 It is.

 [0032] However, the film in the above state is generally too low in sensitivity with an official FT-IR (Fourier transform infrared spectrometer), and cannot be measured with a total reflection analysis of a prism with a side of 5 mm. I think that the.

[0033] Next, after the above measurement, the deuterium (D 2) plasma is generated by leaving the inside of the chamber as it is. For 2 seconds. Before and after this measurement was performed using the same large area FT-IR-ATR as above. The measurement was 10cm- ¹ increments from the wave number 1400cm- ¹ to 2300cm- ^1. Deuterium (D) plastic

 Figure 7.B shows the difference in absorbance before and after the zuma. Absorbance due to absorption of (SiH) bond

 2 n

And the absorbance around 1550 cm ¹ due to SiD binding decreased. Figure 7. B

 2

 From this result, it is clear that it is possible to detect an increase or decrease in absorption due to vibration absorption of the attached film.

 [0034] After cleaning the plasma generator 1000 in FIG. 4 and the probe surface, CF is introduced.

 Then, plasma was generated for 1 second. Large area FT-IR-ATR before and after CF plasma

 4 8

Measurement was carried out. The change in absorbance is shown in Figure 7.C. Wavenumbers 1160 cm ¹ and 1240 cm This peak due to asymmetric stretching vibration was detected, and a peak due to symmetrical stretching vibration was detected at 1210 cm ¹ . In the apparatus of this embodiment, a mirror with high reflectivity can be realized in this entire wavelength band, and the same measurement may be possible if the output of the light source can be increased in this wavelength band. Even with cavity ring-down spectroscopy using the outer wall of a small probe, it is considered that the same results as in Fig. 7.A to Fig. 7.C can be obtained by measurement. Example 3

 [0035] As shown in FIG. 8, a single rod 10 having a diameter of 5 cm is used as an optical waveguide, and a prism 105 is formed by using a prism 13 having a triangular prism shape whose bottom surface is a right isosceles triangle and a mirror 20. . In addition, in order to protect the quartz rod 10, it was configured to cover with the SUS cylinder 100. A QCW semiconductor laser 35 was used as the detection light generator. The detection light had a pulse peak power of 12 W and a wavelength of 808 nm. The mirror 20 had a wavelength of 808 nm and a reflectivity of 99.9% or more. A small photomultiplier tube (PMT) was used as the light receiver 40. Even after the incident pulse light is turned off, the light confined in the cavity is reflected many times, and a part of the light is emitted from the high-reflection mirror 20. As can be seen, a waveform in which the light intensity decays exponentially with respect to time was observed. Figure 9 is a semilogarithmic graph with the logarithmic vertical axis, and the decay life of the cavity can be measured from the slope of the graph. The optical path length L of the cavity was 1.4m. Measure the decay lifetime τ of the above cavity with no sample attached (time until the light intensity of the first detection light reaches lZe light intensity)

 0

As a result, it was 6310 ± 5 ns. The attenuation lifetime τ is the optical path length L of the cavity (mirror or Assuming that the light intensity is R times (0 to 1 -R <<1) by each mirror, there is a relationship such as the following equation (1).

[Equation 1]

L N 1

 = N, Λ = —

 0 c e

L -1 L 1

 „= (·, · Ο <1-R 1) --- (1)

 0 c InR c 1 -R where c is the speed of light. Next, the probe was inserted into the plasma apparatus 1000 having the configuration shown in FIG. 4, and amorphous silicon having a thickness of about lOOnm was formed on the side surface 131 of the prism 13 having the triangular prism shape, which is the tip of the probe. At this time, the decay life of the cavity was measured by changing the film forming temperature. As shown in Table 1, the decay life τ of the three samples was measured. As for other film forming conditions, SiH 100% was supplied at a flow rate of 12 sccm, and the pressure was 0.4 Pa. The film thickness is measured

 Four

After that, it was measured using a step gauge. The results are shown in Table 2. The absorbance A for each sample is obtained by the equation (1), and the absorption coefficient is obtained by dividing the absorbance A by the film thickness.

[Equation 2]

1 1

 A (2)

 c where 0 is the optical path length of the cavity, c is the speed of light.

[Table 1] Sample No. Temperature (° c) Film thickness (nm)

 1 100 100

 2 150 100

3 150 200 [Table 2]

[0037] From the results in Table 2, it can be seen that the absorption coefficient varies depending on the film forming temperature, and that the absorption coefficient is almost the same regardless of the film thickness if the film forming temperature is the same. From this, it can be seen that the present invention can confirm whether or not a desired film has been formed, and whether or not the state of the amorphous silicon is appropriate in this embodiment. Further, the absorbance was summer and sensitivity of 10 ^_6 Abs per LOOnm. This indicates that the measurement can be performed with high sensitivity of about three orders of magnitude compared to conventional absorbance analyzers, and one order of magnitude higher than the refractive index measurement sensitivity using a relatively sensitive ellipso.

 Example 4

[0038] Figure 1. C probe 103 can be used to perform cavity ring-down spectroscopy of DNA solutions. Figure 1. A heater and a temperature sensor are attached to the prism 13 of the probe 103 of C, and a DNA solution of about 200 base pairs (concentration ^10—1Q mol / 1, capacity 10 μ 1) near the reflection point of the optical path on the side of the prism 13 Good to attach!

 [0039] Measurement data of ultraviolet absorption using a deuterium lamp as the light source and ultraviolet light having a wavelength of 260 nm as detection light is shown. Fig. 10 (a) shows a plot of the temperature differential curve of the amount of absorbed UV light when the temperature is raised from room temperature to 90 ° C with a heater. Furthermore, the same experiment was performed for DNA that differs from the above DNA by only one base pair, and the results are shown in Fig. 10 (b).

 [0040] From FIG. 10, it can be understood that two extremely different amounts of DNA that differ by only one base pair have distinctly different peaks in the temperature differential curve of the amount of absorption of ultraviolet light. It is considered that similar data can be obtained by cavity ring-down spectroscopy using the apparatus of the present invention.

[0041] From FIG. 10, as an alternative to the method of using fluorescent molecules to determine single nucleotide polymorphisms used in the currently used real-time polymerase chain reaction apparatus, the cavity ring of the present invention is used. It is suggested that down spectroscopy can be used. In other words, by arranging multiple small probes in an array, there is no need for fluorescent modification of DNA. It can be used as a method for determining single nucleotide polymorphisms. Further, as described above, according to this example, detection is possible with a very small amount of DNA.

[Modification]

 FIG. 11 shows two other configuration diagrams of the probe for the cavity ring-down spectroscopy according to the present invention. FIG. 11. A is a configuration diagram showing the configuration of the probe 301 having the spherical cavity 15. Detection light is introduced into the spherical cavity 15 of the probe 301 from an arbitrarily set position, and reflected on the surface of the spherical cavity 15 a desired number of times. At this time, the light extraction portion 150 is provided at one place on the surface of the spherical cavity 15.

[0043] Fig. 11. A spherical cavity 15 of A uses a CaF sphere with a diameter of lcm as an Nd: YAG laser.

 2

 A quadruple pulse laser is incident through an optical fiber 11. The light extraction section 150 is provided at a position 90 degrees from the incident position, taking into account the central force of the Ca F sphere. Example 4 and CaF spherical surface

twenty two

 Similarly, attach two kinds of DNA in order (shown as sample in Fig. 11. A), and heat the CaF sphere.

 If the experiment similar to Example 4 is performed with 2 and the temperature sensor 60 attached, it is considered that the same result as in FIG. 10 can be obtained. In other words, it shows that a smaller multi-array sensor can be realized by using a smaller spherical cavity 15, that is, a spherical cavity having a diameter of 10 m to 1 mm.

 FIG. 11. B is a configuration diagram showing a probe 302 using a cylindrical cavity 16. The columnar cavity 16 may be replaced with a polygonal column. In fact, in Figure 11.1B, which shows eight reflective surfaces, the cylindrical cavity 16 may be replaced with a regular octagonal prism. The probe 302 in FIG. 11.B can be used in the same manner as the probe 301 in FIG. 11.A. The heater and temperature sensor 50 may be removed. Furthermore, the cylindrical cavity 16 of the probe 302 in FIG. 11.B may be any polyhedron designed as desired. The tips of the two optical fibers 11 and 12 are preferably formed in the shape of a total reflection mirror and coupled to a cylindrical (disk-shaped) cavity 16 by an evanescent wave. In other words, the evanescent wave at the tip of the optical fiber 11 is coupled with the cylindrical (disk-shaped) cavity 16 to introduce light into the cavity 16, and the evanescent wave of the cylindrical (disk-shaped) cavity 16 is emitted. Light is detected from the optical fiber 12 by coupling to the tip of the fiber 12.

Example 5 FIG. 12 is a detailed configuration diagram of the cavity according to the present embodiment. As shown in Fig. 12, the multilayer mirrors 110 and 120 formed at the tips of the optical fibers 11 and 12 are used as high-reflection mirrors, and the detection light is incident on the hexagonal prism (plate) -shaped microprism cavity 17 for the cavity. Circulate the inside. In these, groove portions 711 and 712 and 717 are provided on a probe base 70 having a silicon substrate force, and optical fibers 11 and 12 and a minute prism cavity 17 are arranged, respectively. The sample is attached to the microprism cavity 17 at the end 7S of the probe base 70. Thus, by providing the groove portions 711 and 712 and 717 of the probe base 70, the optical axes of the optical fibers 11 and 12 and the hexagonal prism (plate) -shaped microprism cavity 17 can be easily aligned, and the evanescent wave can be transmitted. Ensure coupling. The micro prism cavity is not limited to a hexagonal column, which may be a polygonal column, a cylinder, or a sphere, even if it is not a hexagonal column (plate).

 [0046] When nothing is applied to the total reflection surface of the microprism cavity 17, the evanescent wave oozes out of the cavity. As already mentioned, it is possible to detect a sample with a higher refractive index than the microprism cavity 17. Can not. Therefore, a metal film 170 having a minute hole as shown in FIG. 13 is formed on the side surface of the minute prism cavity 17. Use silver. At least on the surface to which the sample adheres, there is a cavity 17 (Fig. 13. A) with a circular aperture 1701 with a diameter less than the wavelength of the detection light, or a slit aperture 1702 with a width less than the wavelength of the detection light. A cavity 17 formed with a grating can be used. In the case of a slit aperture, when S-polarized light is incident on the entire reflecting surface, the slit is longer than the wavelength, so if a sample with a high refractive index is attached, nothing can be done. Leakage makes measurement impossible. However, when P-polarized light is incident, only the near-field light oozes out of the aperture, the propagating light does not leak, the light is confined in the cavity, and cavity ring-down spectroscopy becomes possible. The metal film 170 is not formed on the surface of the microprism cavity 17 for coupling with the optical fibers 11 and 12.

FIG. 14 shows an overall view of an optical system in which the cavity ring-down spectroscopy is performed using the cavity of FIG. 13.B. As the laser, a tunable laser device 36 using an optical fiber type femtosecond laser was used. An optical system using an optical fiber is configured, and the reference mirror (Ref) is scanned by the homodyne detector 401 by scanning the movable mirror 80 at a constant speed to adjust the optical path length. The interference intensity peak was obtained. As a sample, an alcohol having a refractive index lower than that of PMMA was used. The use of other liquids having a refractive index lower than that of PMMA and gases such as NO as a sample can be realized with a coupling head using evanescent waves. However, when a high refractive index material such as polycarbonate is used as the sample, coupling with near-field light is required. Figure 15 shows the measurement results with the wavelength fixed at 1.55 / zm. As shown in Fig. 15, it is possible to capture the attenuation from the first to the third lap that circulates in the cavity 17, and the absorption coefficient can be obtained from this. If the wavelength of the wavelength tunable laser is changed, the wavelength dependence of the absorption coefficient can be measured with high sensitivity continuously in the wavelength range from 1.1 m to 2 μm.

The reason why the graph of FIG. 15 is obtained is as follows.

 First, if the optical path length extended for each ring-down is set to “2L”, the speed of light is c, and the time interval between adjacent ring-down lights is 2LZc. That is, the optical pulse output from the cavity includes transmitted light S, S, S, S,... That passes through in the shortest time. These intervals are

 1 2 3 4

 Let T be the pulse period. Transmitted light S time After 2LZc, recirculate once in the cavity.

 P 1

 Ringdown light L force After that time 2LZc, after 2LZc, ringdown that makes two rounds in the cavity

 11

 Ring-down light is output in the order of the light L force at time intervals of 2LZc. This is transmitted light S,

12 2

The same applies to S and S. By adjusting the optical path length “2L” and the pulse interval T, one

3 4 p

 It is easy to ensure that the set of ring-down light following the transmitted light does not overlap the next set of transmitted light. This is shown in Figure 16.A. The width of 2aZc is the case where the mirror is vibrated in the application example described later.

[0049] On the other hand, a transmitted light pulse and a homodyne detection follow a set of ring-down light which is a reference light signal light via another path. Assuming that the optical path length of the reference light is completely matched with the optical path length of the transmitted light that passes through in the shortest time, the homodyne detection of the reference light and the signal light is the same as the reference light noise. Let A be the detection output at this time. Next, if the optical path length of the reference light is completely matched with the optical path length of the ring-down light that makes one round within the cavity, the homodyne detection of the reference light and the signal light is also the same as the pulse of the reference light. . At this time, the detection output is αΑ (0 <α <1). Similarly, assuming that the optical path length of the reference light is exactly the same as the optical path length of the ring-down light that is η-circulated in the cavity, the reference light and the signal light The homodyne detection is also the same as the reference light pulse, and the detection output is _α ^η Α (0 <a <1).

 However, it is not always easy to completely match the optical path length of the reference light with the optical path length of the transmitted light that passes through in the shortest time and the optical path length of each ring-down light. This is a difficulty that comes from using signal light with a short pulse width (eg, femtosecond width). Therefore, a movable mirror 80 is provided in the optical path of the reference light. Then, if the moving amount of the movable mirror 80 is made longer than the cavity length 2L, the optical path length of the reference light is almost completely equal to the optical path length of the transmitted light that passes through in the shortest time and the optical path length of each ring-down light that has n rounds the cavity. Matching can be easily achieved. The cavity length (the optical path length extended for each ringdown) is 2L force mm, so every 2 mm of the movable mirror 80 moves, the optical path length of the reference light is increased by 4mm, and the increase in the optical path length is 1 It corresponds to the optical path length extended every ring-down. Therefore, in Fig. 15, homodyne detection is performed every 2 mm.

 [0051] Another aspect of the present embodiment will be described. Since the coherence length of this laser is about several tens of μm, it is possible to use a cavity size of about 30 m. As a result, if it is possible to repeatedly measure the light response of the absorbing material, it is possible to measure phenomena of 300 ps or more. Furthermore, a supercontinuum light with a wavelength range from 1.1 μm to 2 μm can be generated using this laser. If this is used, the coherence length is several / zm and the diameter of the cavity is several / zm or less, which can be micronized, and it is possible to measure the absorption change of the absorbing material at a high speed of about 20 ps. In addition, it is possible to make hundreds of these sensor heads at a time by using micromachine technology. By creating a waveguide, a compact high-speed absorption spectroscopy system that can analyze many samples at once. Construction is also possible, making it ideal for applications in the bio and medical fields.

[0052] [Application example]

 In Example 5, the following method may be used to further improve the SZN ratio of the signal.

It is assumed that the movable mirror 80 provided in the optical path of the reference light can vibrate. Then, due to vibration of the movable mirror 80, adjacent pulses of the reference light pass through different optical path lengths, and the pulse interval of the reference light reflected by the mirror is longer or shorter than the previous reflection. At this time When the amplitude a of the movable mirror is shortened, the time change 2aZc of the pulse due to the change in the pulse interval of the reference light can be made smaller than the time interval 2LZc between the adjacent ring-down lights. In this way, the optical path length of the reference light branched from the signal light having a desired pulse frequency (pulse interval) is vibrated by a movable mirror that can be oscillated, so that the optical path length of the reference light is changed to that of the transmitted light and each ring-down light. It can be easily achieved to match the optical path length almost perfectly. In this case, the relationship shown in FIG. The change in pulse time 2a Zc is also shown in Figure 16.A.

 Furthermore, if the mirror is powered in one direction while vibrating, and the optical path length of the reference light is changed in the direction of lengthening (or shortening) as a whole while vibrating, the detection output can be reduced to the shortest time in one measurement. And homodyne detection between the transmitted light passing through the reference beam and the reference beam, homodyne detection between the ring-down beam and the reference beam that makes one round in the cavity, homodyne detection between the ring-down beam and the reference beam that makes two rounds in the cavity, and so on. be able to.

[0053] In FIG. 16.B and below, the interference between the above two pulse trains will be described with specific numerical values as examples. The following is a case in which the cavity length 2L is longer than 8 mm, which is the total vibration secondary 2a of the movable mirror 80, which is larger than 4 mm in the fifth embodiment. In other words, the movable mirror 80 is configured to interfere only with a specific number of ring-down pulses in one vibration cycle.

[0054] The signal light, the pulse width lOOfs (1 X 10- ¹³ seconds), pulse interval 2 X 10- ⁸ seconds and (pulse frequency 50 MHz), the vibration of the vibration mirror placed in the middle of the reference beam Set the frequency to 20Hz. In addition, the optical path length of the reference light coincides with the optical path length of the signal light at the vibration center of the mirror. The mirror shall vibrate ± 4mm from its position.

[0055] If the mirror position is X (mm) at time t seconds, and t = 0 and x = 0 (vibration center), then xt can be obtained. The mirror speed v (mmZ seconds) is v = 160 π cos40 π t, where t = 0 and v = 500 mmZ seconds. Then the pulse interval mirror between reaches arrives two pulses of 2 X 10- ⁸ seconds of the reference beam to 1 X 10- moving the optical path difference becomes 2 X 10-. This pulse interval of the reference light reflected by the mirror one is meant 6. 67 X 10- ¹⁷ seconds longer or shorter than that before the reflection.

Then, for example, with the signal light and the reflected reference light, the 0th pulse is as shown in FIG. 6 just has shifted by 1 X 10- ¹³ sec pulse width, than the pulse interval of the pulse interval of the reference light side of the subsequent early instrument reflected towards the pulse time of the reference light side after reflection signal light. When 67 X 10 "1 ⁷禾少lengthヽ, since it is 1 X 10- ¹³禾少÷ 6. 67 X 10- ¹⁷禾少= 1500, the reference light side after reflection at 1500 Roh less th pulse and The pulse of the signal light coincides, and at the 3000th pulse, the signal light and the reference light after reflection are shifted by exactly 1 X ^10-13 seconds of the pulse width, and the time of the pulse on the reference light side after reflection is later It made. since the pulse interval of the signal light is 2 X 10- ⁸ seconds, the time interval of the 0 pulse and the 3000 pulse is 6 X 10- ⁵ sec.

When such signal light and reflected reference light are made to interfere and homodyne detection is performed, an output as shown in FIG. 16. C is obtained. Figure 16. Interference occurs between the signal light and the reflected reference light during the 3000th pulse in state B. The 0th pulse is just 0, the 1500th pulse is the maximum, and the 3000th pulse is just 0, 16. 2999 peaks below the C envelope (indicated by the dotted line). The 2999 peaks of the envelope and its lower side is present between 6 X 10- ⁵ seconds, mirrors does not exist until 0.05 seconds after returning to the original position. That is, 300 0 peaks of the envelope and its lower side is present between 6 X 10- ⁵ seconds 0.05 seconds, not present in other time.

[0058] Looking at this "macroscopic", becomes Rukoto occur at a very sharp peak 0.05 second intervals of width 6 X 10- ⁵ sec (Figure 16. D). By passing this through a low-pass filter having a cutoff frequency corresponding to the vibration frequency of the movable mirror 80, it is possible to obtain an envelope of an interference signal between the ring-down light and the reference light. In this way, measurement with a high SZN ratio becomes possible.

The above occurs naturally even if the pulse waveform is not square wave as shown in Fig. 16.B. Also, the interference difference between the 1500th pulse in Fig. 16.B and the preceding and following pulses is as small as a phase difference of 2πZ80, for example, there are 18.4 waves per pulse at a wavelength of 1.63 / zm. Then, interference between multiple sets of signal light near the envelope peak and the reference light after reflection produces an intensity substantially equal to the intensity of the peak of the envelope, so the pulse of the signal light and the reflected light of the reference light There is no need to adjust it so that the phases are perfectly matched. Further, it is not necessary to adjust the position of the vibration center of the mirror so that the optical path length of the reference light reflected there completely matches the optical path length of the signal light. That is, the optical path length of the reflected reference light is within the range where the mirror vibrates. Thus, it is sufficient if there is a position that completely matches the optical path length of the signal light. Therefore, homodyne detection with signal light can be easily performed by guiding a pulse train having a sufficiently high pulse frequency to the reference light path with respect to the vibration frequency and amplitude of the mirror.

 [0059] In this way, since it is sufficient if the optical path lengths are almost the same, even if the vibrating mirror is moved in the direction of the optical path, there are a plurality of places where the optical path lengths match during vibration. As long as it exists, homodyne detection can be performed easily. Then, the oscillation center of the vibrating mirror is the optical path length of the reference light in the optical path length of the transmitted light S, S, S, S,.

 1 2 3 4

 Position where the lengths coincide, Figure 16. A single ring-down light (one round in the cavity) L,

 11

Position where the optical path length of the reference light matches the optical path length of L 1, L 2, L 3,...

21 31 41

 Down light (two rounds in the cavity) Light of reference light in the optical path length of L, L, L, L, ...

 12 22 32 42

 Position at which the path lengths match .... Fig. 16. n times of ring-down light (with n turns inside the cavity) The optical path length of the reference light matches the optical path length of L, L, L, L, ... Do not move

In 2n 3n 4n

As shown in Fig. 16. E, interference with transmitted light that passes through in the shortest time, interference with one-time ring-down light (one round inside the cavity), and twice-ring-down light (two inside the cavity) interference between those peripheral), · · ·, detected n times the ring down light (within Kiyabiti interference with n peripheral and ones), as a very sharp peak of each double several widths 6 X 10- ⁵ seconds be able to. By passing this through a low-pass filter having a cutoff frequency corresponding to the vibration frequency of the movable mirror 80, envelopes of the respective interference signals can be obtained. Thus, by moving the movable mirror 180 while vibrating it with a predetermined amplitude, it is possible to measure the absorption coefficient with improved SZN.

[0060] A summary of all the above examples will be described. In the present invention, for example, the sample is attached to the total reflection surface of the prism of FIG. 1 or the like, or the sample is attached to the surface of the microprism of FIG. 11 to reduce the absorption of the evanescent wave or near-field light. This method is used for detection. By connecting an optical fiber with a desired length, the detection light can be analyzed at a position away from the sample force. In other words, the state in the reaction vessel as shown in Fig. 3 can be traced outside. For example, in the measurement of the state in the apparatus shown in FIG. 3, the present invention can be applied even during film growth, as well as when film growth is sufficiently slow, or can be arbitrarily interrupted and restarted. Figure 1 etc. A prism of the order of several centimeters and two mirrors (total reflection at two locations) When used, it is easy to make fine adjustments of the probe and the optical axis. It is easy to operate and has high measurement accuracy. As shown in Fig. 8, it can also be implemented with one quartz rod and one mirror. In addition, the microprism shown in FIG. 11 is useful for analyzing a small amount of samples at once as described above.

Industrial applicability

 The present invention provides a protective film that influences the selectivity of the etching process, a film quality of the deposited film of the thin film deposition process, a control of the film thickness and process reproducibility, a highly sensitive measurement and distribution measurement of the film quality and film thickness of the deposited film Or, it can be applied as a real-time sensor for polymerase chain reaction (PCR) of DNA or as a sensor for identification and quantification of minute samples such as living organisms.

Claims

The scope of the claims  [1] A probe used for cavity ring-down spectroscopy,  A first mirror and a second mirror that reflect light;  The first mirror and the second mirror are formed with at least two total reflection or high reflection surfaces, and detection light is transmitted between the two mirrors via the total reflection or high reflection surface. A cavity that forms an optical path to be reflected, and  A first optical waveguide connected to the first mirror, allowing the detection light to enter the cavity through the first mirror;  A second optical waveguide connected to the second mirror, which transmits the second mirror and outputs a part of the detection light from the cavity;  Have  An object for measuring an absorption coefficient is attached to at least one outer surface of the total reflection or high reflection surface, and the absorption of the evanescent wave or near-field light oozing out from the total reflection or high reflection surface force is detected. A probe for cavity ring-down spectroscopy. [2] A probe used for cavity ring-down spectroscopy,  A first optical waveguide and a second optical waveguide;  A reflector formed continuously at the tip of the first optical waveguide and the second optical waveguide and having at least two total reflection or high reflection surfaces;  A first mirror formed on a light incident end face of the first optical waveguide;  A second mirror formed on the light emitting end face of the second optical waveguide;  Have  From the first mirror, the first optical waveguide, the reflector, the second optical waveguide, and the second mirror, detection light is transmitted between the two mirrors via the total reflection or high reflection surface. Form a cavity that reflects any time,  An object for measuring an absorption coefficient is attached to at least one outer surface of the total reflection or high reflection surface, and the absorption of the evanescent wave or near-field light oozing out from the total reflection or high reflection surface force is detected. A probe for cavity ring-down spectroscopy. [3] A probe used for cavity ring-down spectroscopy, An optical waveguide;  A first total reflection or high reflection mirror formed at one end of the optical waveguide and having at least one opening having a width equal to or smaller than the wavelength of the detection light;  A second mirror formed at the other end of the optical waveguide;  Have  From the first total reflection or high reflection mirror, the optical waveguide, and the second mirror, a cavity that reflects the detection light arbitrarily between the two mirrors is formed,  An object whose absorption coefficient is measured is attached to the outer surface of the first total reflection or high reflection mirror to detect the absorption of near-field light that has exuded the first total reflection or high reflection mirror force. Probe for cavity ring-down spectroscopy. [4] Of the total reflection or high reflection surface, a total reflection or high reflection layer in which at least one opening having a width equal to or smaller than the wavelength of the detection light is formed on a surface to which an object whose absorption coefficient is to be measured is attached. 3. The cavity ring-down spectroscopy probe according to claim 1, wherein absorption of near-field light that has exuded from the total reflection or high reflection layer is detected.  [5] The cavity ring-down spectroscopy according to [3], wherein the first total reflection or high reflection mirror has a grating-like opening formed in a reflecting member and having a width equal to or smaller than the wavelength of the detection light. Probe. [6] The cavity ring dow according to claim 4, wherein the total reflection or high reflection layer has a lattice-like opening formed in the reflecting member and having a width equal to or smaller than the wavelength of the detection light. Probe for optical spectroscopy.  [7] The cavity described in any one of claims 1 to 6, wherein the detection light is a super-continuum laser beam or a femtosecond laser beam of a soliton pulse laser beam. Probe for ring-down spectroscopy. [8] A cavity ring-down spectroscopy method, A total reflection or high reflection layer having at least one aperture having a width equal to or smaller than the wavelength of the detection light, which totally reflects or highly reflects the detection light on the outer wall surface to which the cavity object is attached; A cavity ring-down spectroscopic method, wherein absorption by the object of near-field light oozing out from the total reflection or high reflection layer is detected.  [9] The cavity ring dow according to claim 8, wherein the total reflection or high reflection layer has a lattice-like opening formed in the reflecting member and having a width equal to or smaller than the wavelength of the detection light. Spectroscopic method.  [10] The periodic pulse light generated by the femtosecond laser, the supercontinuum light, or the soliton pulse light is bifurcated into the measurement light and the reference light, and the measurement light is any one of claims 1 to 7. 2. The probe according to claim 1 is input to the first optical waveguide, the reference light is incident on a transmission path whose length periodically varies, and the output light from the second optical waveguide of the probe; A cavity ring-down spectroscopic method, wherein absorption by the object is detected by performing homodyne detection by interfering with reference light propagated through a transmission line.