A tunable infrared polarization detector based on phase change material and a preparation method thereof

Abstract

The application provides a tunable infrared polarization detector based on a phase change material, comprising a photodetector and a micro-polarization array integrated on the photodetector, wherein the micro-polarization array comprises a plurality of polarization units in different polarization directions; the polarization unit comprises a silicon dioxide substrate and a polarization maintaining element atom and a half-wave plate-like polarization conversion element atom deposited on the silicon dioxide substrate; the polarization maintaining element atom is a nanometer cylinder deposited on the silicon dioxide substrate by using a phase change material; and the half-wave plate-like polarization conversion element atom is a nanometer cuboid deposited on the silicon dioxide substrate by using a phase change material. The application can easily realize polarization light modulation by controlling the polarization characteristics of incident light through super surface design.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of light detection technology, in particular to a tunable infrared polarization detector based on phase change material and a preparation method. BACKGROUND

[0002] With the continuous improvement of electromagnetic field theory and technology, metamaterials and metasurfaces have received extensive attention in the academic community. With the continuous development of semiconductor technology, the combination of metasurface technology and semiconductor technology gradually exhibits excellent characteristics in optical design, and optical metasurfaces exhibit unprecedented light property control capabilities on a subwavelength scale. In particular, multifunctional polarization metasurfaces that integrate different functions on a single platform using the polarization properties of light can greatly help miniaturize photonic systems.

[0003] In terms of replacing traditional optical design, one important application of metasurface optical technology is in the design of micro-lenses. In traditional optical design based on refractive lenses, the size of visible light lenses is difficult to be small, so for some future applications that require size and weight, new smaller and lighter lenses are getting more and more attention, and metasurface technology can well meet this demand. Metasurface lenses can greatly reduce the size of lenses and improve various parameters (such as light transmission efficiency) of lenses by using semiconductor lithography technology on silicon or glass crystals to realize large-scale subwavelength device arrays. In addition to thin lenses, metasurface technology can also achieve functions that are difficult to achieve in traditional optical design. For example, optical metasurfaces have been widely studied in recent years. It is usually composed of an array of periodically or quasi-periodically arranged nanostructures (also known as meta-atoms), and carefully designed structures can manipulate the properties of light in the subwavelength range. SUMMARY

[0004] In order to solve the technical problem that the polarization transmittance and extinction ratio of the integrated polarization detector after processing are not adjustable in the prior art, one purpose of the present application is to provide a tunable infrared polarization detector based on phase change material, characterized in that the detector comprises:

[0005] a photodetector, and a micro-polarization array integrated on the photodetector, the micro-polarization array comprising a plurality of polarization units in different polarization directions;

[0006] The polarization unit comprises a silicon dioxide substrate and a polarization-preserving meta-atom and a half-wave plate-like polarization conversion meta-atom deposited on the silicon dioxide substrate.

[0007] The polarization-preserving meta-atom is a nanocylinder deposited on the silicon dioxide substrate using a phase change material.

[0008] The quasi-half-wave plate polarization conversion element atom is: a nano cuboid deposited on the silica substrate by using a phase change material.

[0009] Further, the phase change material is one or more of: antimony trisulfide (Sb2S3), antimony triselenide (Sb2Se3), binary germanium-doped selenide (GeSe3), or ternary Ge2Sb2Te5.

[0010] Further, the thickness of the polarization maintaining element atom and the quasi-half-wave plate polarization conversion element atom is 320 nm.

[0011] The center distance between the polarization maintaining element atom and the quasi-half-wave plate polarization conversion element atom is 240 nm.

[0012] Further, the width and length of the quasi-half-wave plate polarization conversion element atom are 82 nm and 154 nm.

[0013] Another object of the present application is to provide a preparation method of a tunable infrared polarization detector based on a phase change material, the preparation method comprising:

[0014] Step S1, preparing a micro-polarization array;

[0015] Cleaning the surface of the silica substrate with acetone, isopropyl alcohol, and deionized water;

[0016] Depositing a 320 nm thick phase change material film on the silica substrate using SiH4 and nitrogen as precursor gases;

[0017] Spin coating a positive electron beam resist (ZEP520A) and conductive glue on the silica substrate to cover the phase change material film;

[0018] Exposing using electron beam lithography and developing in a developer (ZED-N50);

[0019] Depositing a 40 nm aluminum film on the surface by electron beam evaporation, stripping the positive electron beam resist (ZEP520A) using ZDMAC film stripper, and patterning the surface,

[0020] The pattern includes: a plurality of pattern units of polarization units corresponding to a plurality of polarization directions; each pattern unit includes a circular pattern corresponding to a polarization maintaining element atom and a rectangular pattern corresponding to a quasi-half-wave plate polarization conversion element atom.

[0021] Using an inductively coupled plasma (ICP) etching machine to etch the pattern on the surface to the phase change material film, so that the phase change material film deposited on the silica substrate forms a plurality of polarization units of polarization directions;

[0022] The residual aluminum is removed from the patterned nanocylinders and nanocuboids by using a wet etching method to obtain a micro-polarization array.

[0023] Step S2, integrating the micro-polarization array on a photoelectric detector.

[0024] Further, the center distance between the circular pattern corresponding to the polarization maintaining element atoms and the rectangular pattern corresponding to the half-wave plate polarization conversion element atoms is 240nm.

[0025] Further, the width and length of the rectangular pattern are 82nm and 154nm.

[0026] The application provides a tunable infrared polarization detector based on a phase change material and a preparation method.

[0027] The application provides a tunable infrared polarization detector based on a phase change material and a preparation method.

[0028] The application provides a tunable infrared polarization detector based on a phase change material and a preparation method. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The structure of the application is shown schematically.

[0031] Figure 2 The structure of the application is shown schematically.

[0032] Figure 3 The structure of the application is shown schematically.

[0033] Figure 4A function relation diagram showing the variation of the main polarization angle, the transmission efficiency and the linear polarization degree of a tunable infrared polarization detector based on phase change material with the atomic diameter of a polarization maintaining element is shown in an embodiment of the present application.

[0034] Figure 5 A function relation diagram showing the variation of the main polarization angle, the transmission efficiency and the linear polarization degree of a tunable infrared polarization detector based on phase change material with the incident polarization angle is shown in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the above and other features and advantages of the present application more clear, the present application is further described below with reference to the drawings. It should be understood that the specific embodiments given herein are for the purpose of explanation and are not to be construed as limiting.

[0036] In order to solve the technical problem that the polarization transmission and the extinction ratio of the integrated polarization detector after processing are not adjustable in the prior art, a structure of a tunable infrared polarization detector based on phase change material is shown in the present application. Figure 1 A structure diagram of a tunable infrared polarization detector based on phase change material is shown in the present application, according to the embodiment of the present application, a tunable infrared polarization detector based on phase change material is provided, comprising:

[0037] A photoelectric detector 200, and a micro polarization array 100 integrated on the photoelectric detector 200. The micro polarization array 100 comprises a plurality of polarization units in different polarization directions.

[0038] As shown in a structure diagram of a polarization unit in the present application, Figure 2 As shown in a structure diagram of a polarization unit in the present application, Figure 3 As shown in a top view of a polarization unit in the present application, an exemplary polarization unit in different polarization directions is taken as an example in the embodiment, the polarization unit comprises a silicon dioxide substrate 101, and a polarization maintaining element atom (PMM) 102 and a half-wave plate-like polarization conversion element atom (PCM) 103 deposited on the silicon dioxide substrate 101.

[0039] The polarization maintaining element atom (PMM) 102 is a nanometer cylinder deposited on the silicon dioxide substrate by using phase change material.

[0040] The half-wave plate-like polarization conversion element atom (PCM) 103 is a nanometer cuboid deposited on the silicon dioxide substrate by using phase change material.

[0041] The phase change material is one or more of antimony trisulfide (Sb2S3), antimony triselenide (Sb2Se3), binary germanium-doped selenide (GeSe3) or ternary Ge2Sb2Te5.

[0042] In a preferred embodiment, the thickness of the polarization maintaining meta-atom (PMM) 102 and the polarization conversion meta-atom (PCM) 103 is 320 nm. The center-to-center spacing between the polarization maintaining meta-atom (PMM) 102 and the polarization conversion meta-atom (PCM) 103 is 240 nm. The width and length of the polarization conversion meta-atom (PCM) 103 is 82 nm and 154 nm.

[0043] In one embodiment, the present application provides a tunable infrared polarization detector based on phase change material, the working wavelength is between 1 to 5 microns.

[0044] The present application is based on the micro-polarization array 100 of the all-dielectric diatomic metasurface, which combines two meta-atoms in a single polarization unit to provide more degrees of freedom for the metasurface design.

[0045] The present application can eliminate the angle installation error by manufacturing several polarization units (polarizers) in different polarization directions on the same silicon dioxide substrate 101, and can further reduce the volume and weight of the sensor by integrating the micro-polarization array 100 and the photodetector into one component, thereby providing favorable conditions for the application of the polarization detection sensor in various fields.

[0046] The principle of the tunable infrared polarization detector based on phase change material provided by the present application is described below.

[0047] The present application designs the polarization maintaining meta-atom (PMM) 102 and the polarization conversion meta-atom (PCM) 103 as nanometer cylinders and nanometer cuboids respectively, and the Jones matrix of the symmetrical structure of the metasurface can be generally represented as:

[0048]

[0049] where |t xx | and |t yy are the transmission amplitudes of the x-axis and y-axis polarized light, and are the phases of the x-axis and y-axis polarized light.

[0050] By applying a rotation / orientation angle a to the structure (polarization unit) relative to the x-axis, the Jones matrix can be described as:

[0051]

[0052] Given that the transmission amplitudes of the polarization conversion meta-atom (PCM) 103 along the x-axis and y-axis are equal, and the phases differ by π, the Jones matrix of the polarization maintaining meta-atom (PMM) 102 and the polarization conversion meta-atom (PCM) 103 can be simplified as:

[0053]

[0054]

[0055] From the above analysis of the Jones matrix of the polarization maintaining element atom (PMM) 102 and the half-wave plate-like polarization conversion element atom (PCM) 103, it can be obtained that the Jones matrix of the double-atom metasurface can be represented as:

[0056]

[0057] When the incident light is elliptically polarized light, its Jones matrix is:

[0058]

[0059] The Jones matrix of the transmitted light of the incident light after passing through the double-atom metasurface can be represented as:

[0060]

[0061] From the above formula M MS and J out It can be concluded that a suitable combination of polarization maintaining element atoms (PMM) 102 and half-wave plate-like polarization conversion element atoms (PCM) 103 can be equivalent to a linear polarizer with a polarization angle equal to the azimuth angle of the half-wave plate-like polarization conversion element atom (PCM) 103.

[0062] The present application in the polarization unit structure, by designing the size, spatial displacement and direction of the nanocylinder, the metasurface can realize dispersion control, pure polarization control or polarization related vector holography. The present application can effectively cooperate by selecting the appropriate size and orientation angle of the nanocylinder, the polarization maintaining element atom (PMM) 102 and the half-wave plate-like polarization conversion element atom (PCM) 103, to become an infrared polarization detector with high transmission efficiency and controllable polarization angle.

[0063] According to an embodiment of the present application, a preparation method of a tunable infrared polarization detector based on a phase change material is provided, comprising:

[0064] Step S1, preparing a micro-polarization array.

[0065] The present application processes the metasurface structure on the quartz sheet (silicon dioxide substrate) by electron beam evaporation and other processes, specifically including the following methods:

[0066] The silicon dioxide substrate surface is cleaned with acetone, isopropanol and deionized water to promote the adhesion of the phase change materials antimony trisulfide (Sb2S3), antimony triselenide (Sb2Se3), binary germanium-doped selenide (GeSe3) and ternary Ge2Sb2Te5 to the silicon dioxide substrate.

[0067] A 320 nm thick phase change material film is deposited on a silicon dioxide substrate using SiH4 and nitrogen as precursor gases.

[0068] A positive electron beam resist (ZEP520A) and conductive glue are spin-coated on the silicon dioxide substrate to cover the phase change material film.

[0069] Exposure is performed using electron beam lithography and development is performed in a developer (ZED-N50).

[0070] A 40 nm thick aluminum film is deposited on the surface by electron beam evaporation, the positive electron beam resist (ZEP520A) is stripped using ZDMAC stripper, and the surface is patterned,

[0071] The pattern includes a plurality of pattern units of polarization units corresponding to a plurality of polarization directions; each pattern unit includes a circular pattern corresponding to a polarization maintaining element atom (PMM) 102 and a rectangular pattern corresponding to a half-wave plate-like polarization conversion element atom (PCM) 103.

[0072] In a preferred embodiment, the center-to-center distance between the circular pattern corresponding to the polarization maintaining element atom and the rectangular pattern corresponding to the half-wave plate-like polarization conversion element atom is 240 nm. The width and length of the rectangular pattern are 82 nm and 154 nm.

[0073] The pattern of the surface is etched to the phase change material film using an inductively coupled plasma (ICP) etching machine, so that the phase change material film deposited on the silicon dioxide substrate forms a plurality of polarization units of polarization directions. During the etching process, the Al film is used as a hard mask.

[0074] The residual aluminum is removed from the patterned nanocylinders and nanocuboids using a wet etching method to obtain a micro-polarization array 100.

[0075] Step S2, integrating the micro-polarization array 100 on a photodetector.

[0076] In order to verify a tunable infrared polarization detector based on a phase change material prepared by the present application, a full-dielectric diatomic metasurface model is constructed by simulation, and evaluation is performed by a tool based on the finite difference time domain (FDTD) method.

[0077] The diatomic metasurface constructed in the simulation software has a phase change material film layer thickness of 320 nm, and the center-to-center distance between the polarization maintaining element atom (PMM) 102 and the half-wave plate-like polarization conversion element atom (PCM) 103 is 240 nm. A half-wave plate-like polarization conversion element atom (PCM) 103 that can act as a truncated waveguide and ensure efficient linear polarization conversion is selected, and the width and length thereof are designed to be 82 nm and 154 nm, respectively.

[0078] For the biatomic metasurface polarizing unit proposed in the present application, it has been analyzed above that the polarization angle of the transmitted light is the same as the orientation angle of the quasi-half-wave polarizing conversion meta-atom (PCM) 103.

[0079] The azimuth angle of the quasi-half-wave polarizing conversion meta-atom (PCM) 103 also represents the angle of the fast axis of the quasi-half-wave polarizing conversion meta-atom (PCM) 103 relative to the x-axis, based on the fixed parameter α equal to 45 degrees.

[0080] In order to make the light beams interfere with each other through the metasurface of the present application and draw a conclusion, the numerical study is carried out on the function relationship between the transmission efficiency and the polarization response of the biatomic metasurface and the diameter of the nanocylinder of the polarization maintaining element atom (PMM) 102. As shown in FIG. 3, the function relationship diagram of the main polarization angle, the transmission efficiency and the linear polarization degree of the transmitted light of a phase change material-based tunable infrared polarization detector of an embodiment of the present application varies with the diameter of the polarization maintaining element atom, for the incident light whose polarization direction is parallel to the x-axis. It can be known that the diameter of the nanocylinder of the polarization maintaining element atom (PMM) 102 has an effect on the transmitted light, and when the diameter of the polarization maintaining element atom (PMM) 102 reaches 116 nm, the simulated transmission efficiency of the metasurface can reach 48.1%, and the linear polarization degree is as high as 0.99. Figure 4

[0081] Further numerical simulation is carried out to evaluate the performance of the designed biatomic metasurface. By changing the angle of the incident polarization angle while keeping other parameters unchanged, the relationship between the transmission efficiency, the main polarization angle and the linear polarization degree and the incident angle can be obtained.

[0082] As shown in FIG. 4, the function relationship diagram of the main polarization angle, the transmission efficiency and the linear polarization degree of the transmitted light of a phase change material-based tunable infrared polarization detector of an embodiment of the present application varies with the incident polarization angle. It can be obtained from the diagram that when the incident polarization angle is 45 degrees and 135 degrees, the maximum transmission efficiency and the minimum transmission efficiency are T max = 96.2% and T min = 0.05%, so the extinction ratio ER = 10Log(T max / min ) = 32.8 dB. In addition, except for the deviation in the range of 125 to 145 degrees (the gray part in the diagram), the main polarization angle and the linear polarization degree can be stably kept at about 45 degrees or close to unity for most incident polarization angles. Figure 5 Figure 5

[0083] ​​​The above analysis can know that the tunable infrared polarization detector and preparation method based on phase change material provided by the application, the polarization angle is related to the phase angle of the polarization conversion element atom (PCM) 103. The single-layer all-dielectric double-atom super surface composed of polarization maintaining element atoms (PMM) 102 and half-wave plate polarization conversion element atoms (PCM) 103 made of phase change materials antimony trisulfide (Sb2S3), antimony triselenide (Sb2Se3), binary germanium-doped selenide (GeSe3) and ternary Ge2Sb2Te5, by changing the diameter of the polarization maintaining element atom (PMM) 102 and the incident polarization angle, the influence on the transmission and polarization response is explored, the application has a maximum transmission efficiency of 96.2% and a maximum current gain of 32.8dB, and the working waveband is 1-5 microns.

[0084] Although the embodiments of the application have been shown and described above, it should be understood that the above-described embodiments are exemplary, and should not be construed as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the application.

Claims

1. A tunable infrared polarization detector based on a phase change material, characterized in that, The probe comprises: a photodetector, and a micro-polarization array integrated on the photodetector, the micro-polarization array comprising a plurality of polarization units in a plurality of polarization directions; wherein the polarization unit comprises a silicon dioxide substrate, and a polarization maintaining element atom and a half-wave-plate-like polarization conversion element atom deposited on the silicon dioxide substrate; wherein the polarization maintaining element atom is a nanocylinder deposited on the silicon dioxide substrate using a phase change material; the half-wave-plate-like polarization conversion element atom is a nanocuboid deposited on the silicon dioxide substrate using a phase change material.

2. The probe of claim 1, wherein, The phase change material is one or more of antimony trisulfide (Sb2S3), antimony triselenide (Sb2Se3), binary germanium-doped selenide (GeSe3), or ternary G S T ​ 3. The probe of claim 1, wherein, The thickness of the polarization maintaining element atom and the half-wave-plate-like polarization conversion element atom is 320 nm. The center-to-center distance between the polarization maintaining element atom and the half-wave-plate-like polarization conversion element atom is 240 nm.

4. The probe of claim 1, wherein, The width and length of the half-wave-plate-like polarization conversion element atom are 82 nm and 154 nm.

5. A method of fabricating a tunable infrared polarization detector based on a phase change material, characterized in that, The preparation method comprises: Step S1, preparing a micro-polarization array; cleaning the surface of the silicon dioxide substrate with acetone, isopropanol, and deionized water; Si A 320 nm thick phase change material film was deposited on a silicon dioxide substrate with silicon and nitrogen as precursor gases; spinning positive electron beam resist and conductive glue on the silicon dioxide substrate to cover the phase change material film; exposing using electron beam lithography, and developing in a developing solution; depositing an aluminum film on the surface after 40 nm of electron beam evaporation, stripping the positive electron beam resist using a film remover, and patterning the surface, wherein the pattern comprises a plurality of pattern units corresponding to the plurality of polarization units in a plurality of polarization directions; each pattern unit comprises a circular pattern corresponding to the polarization maintaining element atom and a rectangular pattern corresponding to the half-wave-plate-like polarization conversion element atom; using an inductively coupled plasma etching machine to etch the pattern on the surface to the phase change material film, so that the phase change material film deposited on the silicon dioxide substrate forms a plurality of polarization units in a plurality of polarization directions; using wet etching to remove the residual aluminum from the patterned nanocylinder and nanocuboid, to obtain a micro-polarization array; Step S2, integrating the micro-polarization array on the photodetector.

6. The production method according to claim 5, characterized by, The center-to-center distance between the circular pattern corresponding to the polarization maintaining element atom and the rectangular pattern corresponding to the half-wave-plate-like polarization conversion element atom is 240 nm.

7. The preparation method according to claim 5, characterized in that, The width and length of the rectangular pattern are 82 nm and 154 nm.

Images