CN112596281B - Spatial light modulator and method of making the same - Google Patents

Abstract

The invention discloses a spatial light modulator, comprising: the reflecting layer is used for reflecting incident waves; a modulation layer disposed on the reflective layer, the modulation layer having adjustable optical properties and comprising a pixel modulation unit; the electrode layer is arranged on the modulation layer and comprises a modulation electrode, the modulation electrode is arranged on the pixel modulation unit, the modulation electrode changes the optical property of the modulation layer by changing the voltage applied to the pixel modulation unit, and the electrode layer has the characteristics of high stability, high robustness, long service life and high modulation speed. The invention also discloses a preparation method of the spatial light modulator, which adopts the modulation electrode to change the optical property of the modulation layer by changing the voltage of the pixel modulation unit so as to realize the modulation of light waves.

Description

Spatial light modulator and its preparation method

technical field

The invention relates to the field of optics, in particular to a spatial light modulator and a preparation method thereof.

Background technique

Optical information processing technology is based on optical devices, uses light waves to carry information, and uses parallel methods to process information. It has the advantages of large information capacity and fast information processing speed. It has important application value in the rapidly developing information age. Areas such as sensors, optical computers, and digital holographic imaging play an important role.

The spatial light modulator is an important optical device in the optical information processing system. It has multiple pixel units and can adjust the optical parameters such as the amplitude and phase of the light wave, so that the optical parameters form a one-dimensional or two-dimensional distribution in space. At present, the main types of spatial light modulators are liquid crystal spatial light modulators. The main functional material of the liquid crystal spatial light modulator is liquid crystal, which also includes the guiding layer and the sealing glue. Connection structures such as sealing glue are easy to move, and there is a problem of weak fixing stability. The operating temperature of liquid crystals usually does not exceed 50°C. Liquid crystals, guide layers, and frame sealants are all organic substances with low temperature stability. They are prone to aging when used under sunlight and high temperature, and have the problems of low operating temperature and short service life. The modulation mechanism of the liquid crystal spatial light modulator usually adopts the electric birefringence effect of the liquid crystal. Due to the minimum uniformity of the thickness of the liquid crystal material and the liquid crystal layer and the limitation of the minimum thickness of the liquid crystal layer, the liquid crystal spatial light modulator has the disadvantage of low modulation speed. The modulation speed is usually on the order of hundreds of Hertz.

Since the liquid crystal spatial light modulator contains many structural parts, the preparation method of the liquid crystal spatial light modulator has the disadvantages of many processing steps, high processing difficulty, high production cost and low yield. The preparation steps of the liquid crystal spatial light modulator generally include the preparation steps of silicon-based complementary metal oxide semiconductor integrated circuits and the steps of bonding and packaging liquid crystal panels. The preparation steps of silicon-based complementary metal oxide semiconductor integrated circuits usually include the first deposition of silicon oxide, the first patterning, ion implantation, the removal of remaining silicon oxide, the second deposition of silicon oxide, the deposition of silicon nitride, the second Patterning, the third deposition of silicon oxide, the deposition of silicon nitride, the third patterning and the preparation of contact holes, gates and electrodes, etc., including a total of 19 steps including 9 depositions, 3 ion implantations and 7 patterning , The yield rate is 90%. The steps of bonding and encapsulating the liquid crystal panel include five steps of preparing the orientation layer, exposing the orientation layer, coating the frame sealant, pouring the liquid crystal and coating the sealant, and the yield rate is 30%. Therefore, the preparation steps of the liquid crystal spatial light modulator are totally 24, and the yield rate is 27%, which is low and the production cost is high. Among them, the number of times of patterning is large, the alignment deviation is large, the preparation of the contact hole is difficult, and the alignment deviation of the coated frame sealant is large, so the processing of the liquid crystal spatial light modulator is difficult.

Contents of the invention

In order to solve the above technical problems, reduce the processing difficulty of the spatial light modulator, and improve the yield of the spatial light modulator, the present invention discloses a spatial light modulator and a preparation method thereof, and the specific scheme is as follows.

A spatial light modulator comprising:

A reflective layer for reflecting incident waves;

a modulation layer, disposed on the reflective layer, the optical properties of the modulation layer can be adjusted, including a pixel modulation unit;

The electrode layer is arranged on the modulation layer, including a modulation electrode, the modulation electrode is arranged on the pixel modulation unit, and the modulation electrode changes the optical properties of the modulation layer by changing the voltage applied to the pixel modulation unit .

According to some embodiments of the present invention, there are multiple modulation electrodes, and the multiple modulation electrodes are arranged in an array on the electrode layer.

According to some embodiments of the present invention, the reflective layer includes at least two layers, and the refractive index of each layer is different; the material of the reflective layer includes one of the following: conductor, semiconductor or insulator.

According to some embodiments of the present invention, the number of layers of the reflective layer is an even number of layers, and the material of the layer with an odd number of layers is SiO ₂ , the thickness is a positive integer multiple of 240nm, and the refractive index is 1.5; the number of layers is The material of the even numbered layers is Ta ₂ O ₅ , the thickness is a positive integer multiple of 190 nm, and the refractive index is 2.0.

According to some embodiments of the present invention, the material of the modulation layer includes one of the following: thermo-optic material, electro-optic material, acousto-optic material or magneto-optic material.

According to some embodiments of the present invention, the electrode layer further includes:

The common electrode pad is connected to the modulation electrode through the lead-out electrode;

The pixel electrode pad is connected to the modulation electrode through the lead-out electrode;

Wherein, the common electrode pad is connected to the negative pole of the external power supply, and the pixel electrode pad is connected to the positive pole of the external power supply; or,

The common electrode pad is connected to the positive pole of the external power supply, and the pixel electrode pad is connected to the negative pole of the external power supply.

According to some embodiments of the present invention, the material of the electrode layer includes one or a combination of the following: metal, alloy and transparent conductive oxide.

A method for preparing a spatial light modulator, comprising:

preparing a reflective layer on the substrate layer;

preparing a modulation layer on the reflective layer, and patterning the modulation layer to prepare a pixel modulation unit;

An electrode layer is prepared on the modulation layer, and the electrode layer is patterned to prepare a modulation electrode, an extraction electrode, a common electrode pad, and a pixel electrode pad;

preparing an insulating layer on the electrode layer, and patterning the insulating layer;

Wherein, the modulation electrode is arranged on the pixel modulation unit, the common electrode pad is connected to the negative pole of the external power supply, and the pixel electrode pad is connected to the positive pole of the external power supply; or,

The common electrode pad is connected to the positive pole of the external power supply, and the pixel electrode pad is connected to the negative pole of the external power supply.

According to some embodiments of the present invention, before patterning the modulation layer, it further includes thinning and polishing the lower surface of the modulation layer, and the upper surface of the reflection layer and the lower surface of the modulation layer to bond.

According to some embodiments of the present invention, preparing the reflective layer, preparing the modulation layer, preparing the electrode layer and preparing the insulating layer include physical methods or chemical methods; the physical methods include one of the following: magnetron sputtering radiation method, ion beam sputtering method, electron beam evaporation method, thermal evaporation method or molecular beam epitaxy method; said chemical method includes one of the following: chemical vapor deposition method, electrochemical method, sol-gel method or hydrothermal method.

Through the above technical solution, the optical properties of the modulation layer are changed by changing the voltage of the pixel modulation unit by using the modulation electrode, thereby realizing the modulation of the light wave. Compared with the liquid crystal spatial light modulator, at the same time, because the inorganic material is used As a reflection layer, a modulation layer, an electrode layer and an insulation layer in a solid state, it has the characteristics of high stability, high robustness, long service life and high modulation speed.

Description of drawings

FIG. 1 schematically shows a schematic structural diagram of a spatial light modulator according to an embodiment of the present invention;

Fig. 2 schematically shows a schematic structural diagram of a spatial light modulator according to another embodiment of the present invention;

Fig. 3 schematically shows a schematic top view of a spatial light modulator according to an embodiment of the present invention;

Fig. 4 schematically shows a schematic top view of a spatial light modulator according to another embodiment of the present invention;

FIG. 5 schematically shows a flowchart of a method for manufacturing a spatial light modulator according to an embodiment of the present invention;

Among them, 100 represents the substrate layer; 200 represents the reflective layer, 201-208 represent the odd layer and even layer of the reflective layer respectively; 300 represents the modulation layer, 301 represents the pixel modulation unit; 400 represents the electrode layer, 401 represents the common electrode pad , 402 denotes a pixel electrode pad, 403 denotes an extraction electrode, 404 denotes a modulation electrode; 500 denotes an insulating layer.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

It should be understood, however, that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of known technologies are omitted to avoid unnecessarily confusing the concept of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the invention. The term "comprising" used herein indicates the presence of features, steps, operations, but does not exclude the presence or addition of one or more other features.

All terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have a meaning consistent with the context of this specification, and not be interpreted in an idealized or overly rigid manner.

The object of the present invention is to provide a spatial light modulator and its preparation method. The problems of weak fixing stability, low operating temperature, short service life and low modulation speed can be solved by using the spatial light modulator. The preparation method of the modulator can solve the problems of many processing steps, high processing difficulty, low yield and high production cost.

In order to solve the above technical problems, the present invention discloses a spatial light modulator and a preparation method thereof, and the specific scheme is as follows.

Fig. 1 schematically shows a schematic structural diagram of a spatial light modulator according to an embodiment of the present invention.

As shown in FIG. 1 , a spatial light modulator includes: a reflection layer 200 , a modulation layer 300 and an electrode layer 400 .

According to some embodiments of the present invention, the reflective layer 200 is used to reflect the incident wave. Specifically, the light wave passes through the electrode layer 400 and the modulation layer 300 in sequence, is reflected in the reflective layer 200, and then passes through the modulation layer 300 and the electrode in sequence. Layer 400 completes the modulation of light waves.

According to some embodiments of the present invention, the reflective layer 200 includes at least two layers, and each layer has a different refractive index; the material of the reflective layer 200 includes one of the following: conductor, semiconductor or insulator.

According to some embodiments of the present invention, the number of layers of the reflective layer 200 is an even number of layers, and the material of the layers whose number of layers is an odd number is SiO ₂ , the thickness is a positive integer multiple of 240 nm, and the refractive index is 1.5; the number of layers is an even number. The layered material is Ta ₂ O ₅ , the thickness is a positive integer multiple of 190 nm, and the refractive index is 2.0.

Fig. 2 schematically shows a structural diagram of a spatial light modulator according to another embodiment of the present invention.

According to some embodiments of the present invention, as shown in FIG. 2 , optionally, the reflective layer 200 includes 8 layers.

Among them, the layers with odd numbers (for example: layer 201, layer 203, layer 205 and layer 207) are made of SiO ₂ , the thickness is a positive integer multiple of 240 nm, and the refractive index is 1.5.

Layers with even numbers (for example: layer 202, layer 204, layer 206, and layer 208) are made of Ta ₂ O ₅ , the thickness is a positive integer multiple of 190 nm, and the refractive index is 2.0.

Through the above structure, the reflectivity of the reflective layer 200 at the wavelength of 1550nm can be made to be 95%.

According to some embodiments of the present invention, the reflective layer 200 is composed of high-refractive-index materials and low-refractive-index materials at intervals between layers, which can achieve higher reflectivity.

According to some embodiments of the present invention, the reflective layer 200 is located below the modulation layer 300, and the reflective layer 200 has a relatively high reflectivity, so the reflective layer 200 can reflect light waves incident from above through the modulation layer 300 back to the top, thereby The modulation of the light wave is realized to form a reflective spatial light modulator.

According to some embodiments of the present invention, the reflective layer 200 has a thickness of 1 nm to 1 mm.

According to some embodiments of the present invention, the reflective layer 200 is a conductor Al. Al has a thickness of 200nm and a reflectance of 90% at a wavelength of 1550nm.

According to some embodiments of the present invention, the modulation layer 300 is disposed on the reflective layer 200 , the optical properties of the modulation layer 300 can be adjusted, and the modulation layer 300 includes a pixel modulation unit 301 .

According to some embodiments of the present invention, the optical properties of the modulation layer 300 are adjustable, including refractive index or absorption coefficient.

According to some embodiments of the present invention, the shape of the pixel modulation unit 301 includes a cube, a cuboid, a cylinder or a trapezoidal cone.

According to some embodiments of the present invention, there are multiple pixel modulation units 301 , and a gap is provided between two adjacent pixel modulation units 301 .

According to some embodiments of the present invention, the material of the modulation layer 300 includes one of the following: thermo-optic material, electro-optic material, acousto-optic material or magneto-optic material.

According to some embodiments of the present invention, the modulation layer 300 is a conductor, a semiconductor or an insulator.

According to some embodiments of the present invention, the structure of the modulation layer 300 is a thin film structure, a nanostructure, a superlattice structure or a photonic crystal structure.

According to some embodiments of the present invention, the modulation layer 300 includes one of the following: Si, Ge, ITO, AZO, ZnO, GaN, AlN, ZnS, SiC, AlP, GaP, Au, Ag, Pt, VO ₂ , LiNbO ₃ , LiTaO ₃ , BaTiO ₃ , Ta ₂ O ₅ or SiO ₂ .

According to some embodiments of the present invention, the modulation layer 300 has a thickness of 1 nm to 1 mm.

According to some embodiments of the present invention, optionally, the modulation layer 300 is BaTiO ₃ . The thickness of BaTiO ₃ is 500nm. BaTiO ₃ is an electro-optic material with an electro-optic coefficient of 105pm/V and a refractive index of 2.1 at a wavelength of 1550nm. It can be understood that the modulation layer 300 is located under the electrode layer 400, and the modulation layer 300 has a large electro-optic coefficient, so applying a voltage to the modulation layer 300 through the electrode layer 400 can change the refractive index of the modulation layer 300, thereby changing the incident light Through the optical path difference of the modulation layer, the modulation of the light wave is realized.

According to some embodiments of the present invention, optionally, the modulation layer 300 is VO ₂ . _The thickness of VO2 is 100nm. VO2 is a thermo _- optic material with a refractive index of 2.1 at a wavelength of 1550nm. It can be understood that the modulation layer 300 is located under the electrode layer 400, so the heat generated by applying a voltage to the electrode layer 400 can change the temperature of the modulation layer 300, thereby changing the refractive index of the modulation layer 300, and then changing the incident light passing through. The optical path difference of the modulation layer 300 realizes the modulation of light waves.

FIG. 3 schematically shows a top view of a spatial light modulator according to an embodiment of the present invention; FIG. 4 schematically shows a top view of a spatial light modulator according to another embodiment of the present invention.

According to some embodiments of the present invention, it can be described in conjunction with FIG. 2. As shown in FIG. 3 and FIG. 4, the electrode layer 400 is disposed on the modulation layer 300, including the modulation electrode 404, and the modulation electrode 404 is disposed on the pixel modulation unit 301. The modulation electrode 404 changes the optical properties of the modulation layer 300 by changing the voltage applied to the pixel modulation unit 301 .

According to some embodiments of the present invention, there are multiple modulation electrodes 404, and the multiple modulation electrodes 404 are arranged in an array on the electrode layer.

According to some embodiments of the present invention, the shape of the modulation electrode 404 includes a cube, a cuboid, a cylinder or a trapezoidal cone.

According to some embodiments of the present invention, the shape of the modulation electrode 404 is consistent with the shape of the pixel modulation unit 301 .

According to some embodiments of the present invention, optionally, the electrode layer 400 is Au. The thickness of Au is 100 nm. The resistivity of the Au material is 2.4×10 ^-8 Ω·m. The modulation electrodes 404 have a length of 1 mm, a width of 1 μm, and a pitch of 1 mm.

According to some embodiments of the present invention, optionally, the length and width of the common electrode pad 401 are both 100 μm.

According to some embodiments of the present invention, optionally, the length and width of the pixel electrode pad 402 are both 100 μm, and the smaller pitch in the vertical direction is 10 μm.

According to some embodiments of the present invention, the width of the extraction electrode 403 is 1 μm, and the smaller distance between the extraction electrode and the modulation electrode in the vertical direction is 1 μm.

According to some embodiments of the present invention, the electrode layer has a total of 16 modulation electrodes 404 arranged in a 4*4 array, and correspondingly, each modulation electrode 404 corresponds to a pixel modulation unit 301 below. The number of the common electrode pad 401 is one, and the common electrode pad 401 is used to connect the negative pole of the external power supply, and is connected to one end of each modulation electrode 404 through the lead-out electrode 403 . The number of pixel electrode pads 402 is 16, and the pixel electrode pads 402 are used to connect the positive pole of an external power supply, and each pixel electrode pad 402 is connected to the other end of a modulation electrode 404 through an extraction electrode 403 . It can be understood that the electrode layer 400 is located above the modulation layer 300, and the common electrode pad 401 and each pixel electrode pad 402 can independently control the voltage on each pixel modulation unit 301, thereby independently controlling the refractive index of the modulation layer 300 , and then realize the two-dimensional distribution of light waves in space.

According to some embodiments of the present invention, the electrode layer 400 further includes a common electrode pad 401 , an extraction electrode 403 and a pixel electrode pad 402 .

According to some embodiments of the present invention, there is a gap between the common electrode pad 401 , the pixel electrode pad 402 , the extraction electrode 403 and the modulation electrode 404 .

According to some embodiments of the present invention, the electrode layer 400 has a thickness of 1 nm to 1 mm.

According to some embodiments of the present invention, the modulation electrode 404 has a length of 1 nm to 1 mm and a width of 1 nm to 1 mm.

According to some embodiments of the present invention, the length of the common electrode pad 401 is 1 nm to 1 mm, and the width is 1 nm to 1 mm.

According to some embodiments of the present invention, the length of the pixel electrode pad 402 is 1 nm to 1 mm, and the width is 1 nm to 1 mm.

According to some embodiments of the present invention, the length of the extraction electrode 403 is 1 nm to 1 mm.

According to some embodiments of the present invention, the distance between two adjacent modulation electrodes 404 is 1 nm to 1 mm.

According to some embodiments of the present invention, the distance between the extraction electrode 403 and the modulation electrode 404 in the vertical direction is 1 nm to 1 mm.

According to some embodiments of the present invention, the common electrode pad 401 is connected to the modulation electrode 404 through the extraction electrode 403 .

According to some embodiments of the present invention, the pixel electrode pad 402 is connected to the modulation electrode 404 through the extraction electrode 403 .

According to some embodiments of the present invention, the common electrode pad 401 is connected to the negative pole of the external power supply, and the pixel electrode pad 402 is connected to the positive pole of the external power supply; or,

The common electrode pad 401 is connected to the positive pole of the external power supply, and the pixel electrode pad 402 is connected to the negative pole of the external power supply.

According to some embodiments of the present invention, the material of the electrode layer 400 includes one or a combination of the following: metal, alloy and transparent conductive oxide.

According to some embodiments of the present invention, the electrode layer 400 includes Ag, Cu, Au, Al, Pt, Ni, Cr, Ti or ITO.

According to some embodiments of the present invention, the electrode layer 400 is Au. The thickness of Au is 100 nm. The resistivity of the Au material is 2.4×10 ^-8 Ω·m. The modulation electrode 404 has a width of 1 μm.

According to some embodiments of the present invention, as shown in FIG. 4, the shape of the modulation electrode 404 is a square frame or a square structure. As shown in FIG. The side length of the square of the electrode 404 is 1 mm. Both the length and the width of the common electrode pad 401 are 100 μm. The length and width of the pixel electrode pads 402 are both 100 μm, and the smaller pitch in the vertical direction is 10 μm. The extraction electrode 403 has a width of 1 μm. The minimum distance between the extraction electrode and the modulation electrode in the vertical direction is 1 μm. The electrode layer has a total of 16 modulation electrodes 404 arranged in a 4*4 array, correspondingly, each modulation electrode 404 corresponds to a pixel modulation unit 301 below. The number of the common electrode pad 401 is one, and the common electrode pad 401 is used to connect the negative pole of the external power supply, and is connected to one end of each modulation electrode 404 through the lead-out electrode 403 . The number of pixel electrode pads 402 is 16, and the pixel electrode pads 402 are used to connect the positive pole of an external power supply, and each pixel electrode pad 402 is connected to the other end of a modulation electrode 404 through an extraction electrode 403 . It can be understood that the electrode layer 400 is located above the modulation layer 300, and the common electrode pad 401 and each pixel electrode pad 402 can independently control the voltage on each pixel modulation unit 301, thereby independently controlling the refractive index of the modulation layer 300 , and then realize the two-dimensional distribution of light waves in space.

Fig. 2 schematically shows a structural diagram of a spatial light modulator according to another embodiment of the present invention.

According to some embodiments of the present invention, as shown in FIG. 2 , the spatial light modulator further includes a substrate layer 100 disposed under the reflective layer 200 .

According to some embodiments of the present invention, the substrate layer 100 is a conductor, a semiconductor or an insulator.

According to some embodiments of the present invention, the material of the substrate layer includes Al, Si, SiO ₂ or Al ₂ O ₃ .

According to some embodiments of the present invention, the thickness of the substrate layer 100 is 1 nm to 1 mm.

According to some embodiments of the present invention, the substrate layer 100 is Si material. The thickness of the substrate layer was 0.4 mm. The substrate layer is mainly used for bearing, which is conducive to achieving high integration. The price of the substrate layer is relatively cheap, which can reduce the production cost.

According to some embodiments of the present invention, the spatial light modulator further includes an insulating layer 500 disposed on the electrode layer 400 .

According to some embodiments of the present invention, the insulating layer 500 is a single crystal material, a polycrystalline material or an amorphous material.

According to some embodiments of the present invention, the insulating layer 500 includes one of the following: SiO ₂ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or Si ₃ N ₄ .

According to some embodiments of the present invention, the thickness of the insulating layer 500 is 1 nm to 1 mm.

According to some embodiments of the present invention, the insulating layer 500 is Al ₂ O ₃ . Al ₂ O ₃ has a thickness of 200nm and a refractive index of 1.9 at a wavelength of 1550nm. It can be understood that the insulating layer has excellent insulating performance and wear resistance, so as to prevent electrode short circuit, prevent the surface of the electrode layer from being oxidized, and protect the surface of the modulation layer.

According to some embodiments of the present invention, the reflective layer 200, the modulation layer 300 and the electrode layer 400 are all solid, and the reflective layer 200, the modulation layer 300 and the electrode layer 400 are all inorganic. The use temperature of inorganic solids is usually higher than that of liquid crystals and other organic substances, which has the advantage of high use temperature. At the same time, the aging resistance of inorganic solids is generally higher than that of organic substances, which has the advantage of long service life, and the positions and relative positions of the reflective layer 200, the modulation layer 300 and the electrode layer 400 are fixed and invariable. Therefore, the present invention Compared with the liquid crystal spatial light modulator in the prior art, the disclosed spatial light modulator has the characteristics of high stability, high robustness and long service life.

In addition, the modulation layer 300 is solid, and the modulation layer 300 is an inorganic substance. The minimum uniformity of the thickness of the inorganic solid modulation layer 300 is better than that of the liquid crystal layer, and the minimum thickness of the inorganic solid modulation layer 300 is one order of magnitude smaller than the thickness of the liquid crystal layer, which has the advantage of high modulation speed. Therefore, the space of the present application The modulation speed of the light modulator is higher than the modulation speed of the liquid crystal spatial light modulator by more than 4 orders of magnitude. Compared with the modulation speed of the liquid crystal spatial light modulator in the prior art, the modulation speed is on the order of 100 Hz. The spatial light modulator disclosed in the present invention The modulation speed can reach the order of megahertz.

Fig. 5 schematically shows a flowchart of a method for manufacturing a spatial light modulator according to an embodiment of the present invention.

As shown in Figure 5, the present invention also discloses a method for preparing a spatial light modulator, including:

S1: preparing a reflective layer 200 on the substrate layer 100;

S2: preparing a modulation layer 300 on the reflective layer 200, and patterning the modulation layer 300 to prepare a pixel modulation unit 301;

S3: Prepare the electrode layer 400 on the modulation layer 300, pattern the electrode layer 400 to prepare the modulation electrode 404, the extraction electrode 403, the common electrode pad 401 and the pixel electrode pad 402;

S4: preparing an insulating layer 500 on the electrode layer 400, and patterning the insulating layer 500;

Wherein, the modulation electrode 404 is arranged on the pixel modulation unit 301, the common electrode pad 401 is connected to the negative pole of the external power supply, and the pixel electrode pad 402 is connected to the positive pole of the external power supply; or,

The common electrode pad 401 is connected to the positive pole of the external power supply, and the pixel electrode pad 402 is connected to the negative pole of the external power supply.

According to some embodiments of the present invention, the patterning process includes photolithography and etching.

According to some embodiments of the present invention, before patterning the modulation layer 300, it also includes thinning and polishing the lower surface of the modulation layer 300, and bonding the upper surface of the reflection layer 200 and the lower surface of the modulation layer 300.

According to some embodiments of the present invention, preparing the reflective layer 200, preparing the modulation layer 300, preparing the electrode layer 400, and preparing the insulating layer 500 include physical methods or chemical methods; the physical methods include one of the following: magnetron sputtering, ion beam sputtering radiation, electron beam evaporation, thermal evaporation, or molecular beam epitaxy; chemical methods include one of the following: chemical vapor deposition, electrochemical, sol-gel, or hydrothermal.

According to some embodiments of the present invention, the manufacturing method of the spatial light modulator disclosed in the present invention includes 4 times of deposition and 3 times of patterning, a total of 7 small steps, far less than that of the liquid crystal spatial light modulator in the prior art There are 24 processing steps. Therefore, the manufacturing method of the spatial light modulator disclosed in the present invention simplifies the processing technology, improves the production efficiency, and reduces the production cost.

In addition, the preparation method of the spatial light modulator disclosed in the present invention only includes processes such as deposition and patterning with low processing difficulty, the number of patterning is small, the alignment deviation is small, and there is no preparation of contact holes and sealing glue. , has the advantages of low processing difficulty, further reduces the production cost and improves the production efficiency.

The yield of the spatial light modulator produced by the preparation method of the spatial light modulator disclosed in the present invention can be as high as 90%. Compared with the yield of 27% of the liquid crystal spatial light modulator in the prior art, the yield is improved and the loss and cost.

The modulation mechanism of the spatial light modulator disclosed in the present invention is to use the change of the optical properties of the modulation layer 300 to modulate the optical parameters of the light waves passing through the spatial light modulator. The spatial light modulator is irradiated with incident light, and some energy (such as electricity and heat, etc.) is applied to the modulation layer 300 through the electrode layer 400 to change the optical properties of the modulation layer 300 (such as refractive index and absorption coefficient, etc.), thereby changing the spatial light modulator. The optical parameters (for example: phase and amplitude, etc.) of the reflected light of the light modulator. The reflective layer 200 is located below the modulation layer 300, and the reflective layer 200 has a high reflectivity for a certain wavelength or a certain wavelength range, so the reflective layer 200 can reflect light waves incident from above through the modulation layer 300 back to the top, thereby Realize the modulation of light waves. The electrode layer 400 is located above the modulation layer 300, the common electrode pad 401 and each pixel electrode pad 402 can independently control the voltage of each pixel modulation unit 301, thereby independently controlling the refractive index of the modulation layer 300, and then realize the light wave in space two-dimensional distribution.

Through the above technical scheme, the optical properties of the modulation layer are changed by changing the voltage of the pixel modulation unit by using the modulation electrode, and then the modulation of the light wave is realized. Compared with the liquid crystal spatial light modulator, the layer and the insulating layer have the characteristics of simple structure, high stability, high robustness, long service life and high modulation speed, and the modulation speed can reach the order of megahertz. Cooperating with the corresponding preparation method, it has many beneficial effects such as few processing steps, low processing difficulty, high yield and low production cost.

So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It should be noted that, in the accompanying drawings or in the text of the specification, implementations that are not shown or described are forms known to those of ordinary skill in the art, and are not described in detail. In addition, the above definition of each component is not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those skilled in the art can easily modify or replace them.

It should also be noted that, in the specific embodiments of the present disclosure, unless otherwise known to the contrary, the numerical parameters in this description and the appended claims are approximate values, and can be obtained according to the requirements obtained through the contents of the present disclosure. Characteristics change. In particular, all numbers expressing compositional dimensions, range conditions and the like used in the specification and claims are to be understood as being modified in all instances by the word "about". In general, the expressed meaning is meant to include a variation of ±10% in some embodiments, a variation of ±5% in some embodiments, a variation of ±1% in some embodiments, a variation of ±1% in some embodiments, and a variation of ±1% in some embodiments ±0.5% variation in the example.

Those skilled in the art can understand that the features described in the various embodiments and/or claims of the present invention can be combined and/or combined in various ways, even if such a combination or combination is not explicitly recorded in the present invention. In particular, without departing from the spirit and teaching of the present invention, the various embodiments of the present invention and/or the features recited in the claims can be combined and/or combined in various ways. All such combinations and/or combinations fall within the scope of the present invention.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (9)

1. A spatial light modulator, characterized in that, comprising: A reflective layer for reflecting incident waves; a modulation layer, disposed on the reflective layer, the optical properties of the modulation layer can be adjusted, including a pixel modulation unit; The electrode layer is arranged on the modulation layer, including a modulation electrode, the modulation electrode is arranged on the pixel modulation unit, and the modulation electrode changes the optical properties of the modulation layer by changing the voltage applied to the pixel modulation unit ; The common electrode pad is connected to the modulation electrode through the lead-out electrode; The pixel electrode pad is connected to the modulation electrode through the lead-out electrode; Wherein, the common electrode pad is connected to the negative pole of the external power supply, and the pixel electrode pad is connected to the positive pole of the external power supply; or, The common electrode pad is connected to the positive pole of the external power supply, and the pixel electrode pad is connected to the negative pole of the external power supply. 2 . The spatial light modulator according to claim 1 , wherein there are multiple modulation electrodes, and the multiple modulation electrodes are arranged in an array on the electrode layer. 3 . 3. The spatial light modulator according to claim 1, wherein the reflective layer comprises at least two layers, each of which has a different refractive index; the material of the reflective layer comprises one of the following : conductor, semiconductor or insulator. 4. The spatial light modulator according to claim 3, characterized in that, the number of layers of the reflective layer is an even number of layers, and the material of layers whose number of layers is an odd number is SiO ₂ , and the thickness is a positive integer multiple of 240nm , the refractive index is 1.5; the material of the layers whose layer numbers are even numbers is Ta ₂ O ₅ , the thickness is a positive integer multiple of 190 nm, and the refractive index is 2.0. 5. The spatial light modulator according to claim 1, wherein the material of the modulation layer comprises one of the following: thermo-optic material, electro-optic material, acousto-optic material or magneto-optic material. 6. The spatial light modulator according to any one of claims 1-5, wherein the material of the electrode layer comprises one or a combination of the following: metal, alloy and transparent conductive oxide. 7. A method for preparing a spatial light modulator, comprising: preparing a reflective layer on the substrate layer; preparing a modulation layer on the reflective layer, and patterning the modulation layer to prepare a pixel modulation unit; An electrode layer is prepared on the modulation layer, and the electrode layer is patterned to prepare a modulation electrode, an extraction electrode, a common electrode pad, and a pixel electrode pad; preparing an insulating layer on the electrode layer, and patterning the insulating layer; Wherein, the modulation electrode is arranged on the pixel modulation unit, the common electrode pad is connected to the negative pole of the external power supply, and the pixel electrode pad is connected to the positive pole of the external power supply; or, The common electrode pad is connected to the positive pole of the external power supply, and the pixel electrode pad is connected to the negative pole of the external power supply. 8. The preparation method according to claim 7, further comprising, before patterning the modulation layer, thinning and polishing the lower surface of the modulation layer, and polishing the upper surface of the reflection layer Bonding with the lower surface of the modulation layer. 9. The preparation method according to claim 7, characterized in that, preparing the reflective layer, preparing the modulation layer, preparing the electrode layer and preparing the insulating layer include physical or chemical methods; the physical method Including one of the following: magnetron sputtering, ion beam sputtering, electron beam evaporation, thermal evaporation or molecular beam epitaxy; the chemical method includes one of the following: chemical vapor deposition, electrochemical, sol Gel method or hydrothermal method.

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