阅读说明：本技术 一种基于超导纳米线的单光子偏振探测器件及其实现装置 (Superconducting nanowire-based single photon polarization detection device and implementation device thereof ) 是由 张伟君 孙兴渠 尤立星 李�浩 王镇 谢晓明 于 2020-03-11 设计创作，主要内容包括：本申请涉及一种基于超导纳米线的单光子偏振探测器件及其实现装置,包括：衬底；像元层,像元层置于衬底上；其中,像元层包括一个或多个超像元单元；每个超像元单元包括至少四个像元单元,像元单元由一条蜿蜒曲折的超导纳米线构成；且每个像元单元的超导纳米线结构的平行方向的角度各不同；利用四个超像元对偏振光的偏振角的光响应计数可以实现对线性偏振光的偏振态求解。与现有的半导体偏振探测器相比,本申请中的超导纳米线结构具有线偏振器和光子探测器的双重功能,不仅集合了超导纳米线结构单光子探测器自身的优点,还具有器件规模可拓展、结构简单等特点,有望应用于微弱光环境下的偏振探测及成像、量子通信、天文观测等。(The application relates to a single photon polarization detection device based on superconducting nanowires and an implementation device thereof, comprising: a substrate; the pixel layer is arranged on the substrate; wherein, the image element layer comprises one or more super image element units; each super pixel unit comprises at least four pixel units, and each pixel unit is formed by a meandering super-conductive nanowire; and the angle of the parallel direction of the superconducting nanowire structure of each pixel unit is different; the calculation of the polarization state of the linearly polarized light can be realized by utilizing the light response count of the four super-pixels to the polarization angle of the polarized light. Compared with the existing semiconductor polarization detector, the superconducting nanowire structure has the dual functions of a linear polarizer and a photon detector, integrates the advantages of the superconducting nanowire structure single photon detector, has the characteristics of expandable device scale, simple structure and the like, and is expected to be applied to polarization detection and imaging, quantum communication, astronomical observation and the like in a weak light environment.)

1. A single photon polarization detection device based on superconducting nanowires is characterized by comprising:

a substrate;

the pixel layer is arranged on the substrate;

the image element layer comprises one or more super image element units, and the super image element units are arranged at equal intervals; the super pixel units comprise at least four pixel units which are arranged at equal intervals; the projection areas of the pixel units on the preset plane are the same, the pixel units comprise superconducting nanowire structures which are arranged in parallel at equal intervals, the superconducting nanowire structures are sequentially connected end to end, and the angle between the parallel direction of the superconducting nanowire structure of each pixel unit in the at least four pixel units and the preset direction is different.

2. The single photon polarization detector based on superconducting nanowires of claim 1, wherein the superconducting nanowires have absorption differences for polarized light in two directions parallel to and perpendicular to the superconducting nanowires, and the polarization extinction ratios of the pixel units in the at least four pixel units are uniformly distributed.

3. The superconducting nanowire-based single photon polarization detection device of claim 1, wherein the superconducting nanowire unit comprises four pixel elements for providing photoresponse counts for polarized light for jointly solving polarization states of linearly polarized light comprising one or more of polarization angle, degree of linear polarization (Do L P), polarization angle (azimuth), S1 parameters for linearly polarized light, and S2 parameters for linearly polarized light.

4. The superconducting nanowire-based single photon polarization detection device of claim 1, wherein the superconducting nanowire structure comprises 1 superconducting nanowire or a plurality of superconducting nanowires of equal spacing, equal length and parallel arrangement.

5. The superconducting nanowire-based single photon polarization detection device of claim 1, wherein the pixel unit is square, circular or triangular in shape.

6. The superconducting nanowire-based single photon polarization detection device of claim 1, wherein the substrate comprises a first layer of silicon dioxide, a first layer of silicon, and a second layer of silicon dioxide;

the first silicon dioxide layer, the first silicon layer and the second silicon dioxide layer are sequentially stacked.

7. The superconducting nanowire-based single photon polarization detection device of claim 6, wherein the substrate further comprises an insulating dielectric layer, a metal grating layer and a metal mirror layer;

the insulating medium layer is arranged on the first silicon dioxide layer;

the pixel layer and the metal grating layer are arranged in the insulating medium layer at intervals; the metal grating layer is arranged above the spacing part of the superconducting nanowires;

the metal reflector layer is arranged on the surface of the insulating medium layer close to the metal grating layer.

8. The superconducting nanowire-based single photon polarization detection device of claim 1, wherein the substrate comprises a light absorption enhancing structure and a second silicon layer;

the light absorption enhancement structure is arranged on the second silicon layer; the light absorption enhancement structure comprises at least two double-layer medium material layers which are sequentially stacked, wherein the double-layer medium material layers comprise two material layers which are sequentially stacked and have different refractive indexes.

9. The superconducting nanowire-based single photon polarization detection device of claim 1, wherein the superconducting nanowire is made of niobium nitride, titanium niobium nitride, tantalum nitride, tungsten silicide or niobium.

10. A superconducting nanowire-based single photon polarization detection implementation device is characterized by comprising:

the device comprises an aspheric collimating lens, a linear polarizer, a half-wave plate, a superconducting nanowire single-photon detector with a split focal plane, a sensor and a processor;

the aspheric collimating lens, the linear polarizer, the half-wave plate and the superconducting nanowire single-photon detector with the split focal plane are sequentially arranged at intervals; the superconducting nanowire single photon detector with a split focal plane comprises superconducting nanowire-based single photon polarization detection as claimed in any one of claims 1 to 9;

the sensor is used for detecting the polarization parameters of single photon polarization detection in a free space sequentially through the aspheric collimating lens, the linear polaroid, the half-wave plate and the superconducting nanowire under the preset condition;

and the processor is used for processing the polarization parameters to obtain the polarization information of the single photon.

Technical Field

The application relates to the field of optical detection, in particular to a single photon polarization detection device based on a superconducting nanowire and an implementation device thereof.

Background

Polarization is an important information of light. Polarization Detection (PD) is an advantageous complement to intensity detection, and can expand the information amount from three dimensions (light intensity, spectrum and space) to seven dimensions (light intensity, spectrum, space, polarization degree, polarization azimuth angle, polarization ellipse and rotation direction), which helps to improve the accuracy of target detection and ground object identification.

The structure of the existing semiconductor polarization detector is generally divided into time-sharing detection, amplitude-dividing detection, aperture-dividing detection and focal plane-dividing detection, wherein the focal plane-dividing structure with the highest integration level integrates micro-polarizers in different polarization directions on the focal plane of a CCD pixel, and every four pixels form an ultra-pixel to realize the real-time detection of Stokes parameters.

However, the matching error between the micro-polarizer and the CCD pixel of the existing semiconductor polarization detector and the uniformity requirement of the extinction ratio of the pixel can raise the difficulty of the process. In addition, the photoelectric detection performance of the existing semiconductor polarization detector depends on a bottom-layer integrated CCD pixel array, the sensitivity generally does not reach the single photon level, and especially the performances in the near-infrared band, such as the detection efficiency of single photons, the dark counting rate, the detection rate, the integration level and the like, still need to be improved.

Disclosure of Invention

The embodiment of the application aims to solve the problems that the matching error between a micro-polarizer and a CCD pixel of the existing semiconductor polarization detector and the uniformity requirement of the extinction ratio of the pixel can improve the difficulty of the process. And the photoelectric detection performance of the existing semiconductor polarization detector depends on a CCD pixel array integrated at the bottom layer, and the single photon detection has the defects of low sensitivity, low performance and the like.

In order to solve the foregoing technical problem, an embodiment of the present application provides a single photon polarization detection device based on a superconducting nanowire, where the detection device includes:

a substrate;

the pixel layer is arranged on the substrate;

the pixel layer comprises one or more super pixel units, and the super pixel units are arranged at equal intervals; the super pixel unit comprises at least four pixel units which are arranged at equal intervals; the projection areas of the pixel units on the preset plane are the same, the pixel units comprise superconducting nanowire structures which are arranged in parallel at equal intervals, the superconducting nanowire structures are sequentially connected end to end, and the angle between the parallel direction of the superconducting nanowire structure of each pixel unit in at least four pixel units and the preset direction is different.

Optionally, the superconducting nanowire pair has absorption difference with respect to polarized light in two directions, i.e., parallel to the superconducting nanowire and perpendicular to the superconducting nanowire, and polarization extinction ratios of the pixel units in the at least four pixel units are uniformly distributed.

Optionally, the super pixel unit includes four pixel units, and the four pixel units are configured to provide a light response count for the polarized light, and the light response count for the polarized light is configured to jointly solve a polarization state of the linearly polarized light, where the polarization state includes one or more of a polarization angle, a degree of linear polarization (Do L P), a polarization angle (azimuth), an S1 parameter of the linearly polarized light, and an S2 parameter of the linearly polarized light.

Optionally, the superconducting nanowire structure includes 1 superconducting nanowire or a plurality of superconducting nanowires arranged in parallel at equal intervals and equal lengths.

Optionally, the shape of the pixel unit is square, circular or triangular.

Optionally, the substrate includes a first silicon dioxide layer, a first silicon layer, and a second silicon dioxide layer;

the first silicon dioxide layer, the first silicon layer and the second silicon dioxide layer are sequentially stacked.

Optionally, the substrate further includes an insulating medium layer, a metal grating layer and a metal mirror layer;

the insulating medium layer is arranged on the first silicon dioxide layer;

the pixel layer and the metal grating layer are arranged in the insulating medium layer at intervals; the metal grating layer is arranged above the spacing part of the superconducting nanowires;

the metal reflector layer is arranged on the surface of the insulating medium layer close to the metal grating layer.

Optionally, the substrate comprises a light absorption enhancing structure and a second silicon layer;

the light absorption enhancement structure is arranged on the second silicon layer; the light absorption enhancement structure comprises at least two double-layer medium material layers which are sequentially stacked and arranged, wherein the double-layer medium material layers comprise two material layers which are sequentially stacked and arranged and have different refractive indexes.

Optionally, the superconducting nanowire is made of niobium nitride, titanium niobium nitride, tantalum nitride, tungsten silicide, or niobium.

In another aspect, a single photon polarization detection implementation apparatus based on superconducting nanowires is provided, and the apparatus includes:

the device comprises an aspheric collimating lens, a linear polarizer, a half-wave plate, a superconducting nanowire single-photon detector with a split focal plane, a sensor and a processor;

the aspheric collimating lens, the linear polarizer, the half-wave plate and the superconducting nanowire single-photon detector with the focal plane are sequentially arranged at intervals; superconducting nanowire single photon detector with a split focal plane comprising a superconducting nanowire-based single photon polarization detection device as claimed in the preceding claims;

the sensor is used for detecting the polarization parameters of a single photon in a free space sequentially through an aspheric collimating lens, a linear polarizer, a half-wave plate and a superconducting nanowire-based single photon polarization detection device under a preset condition;

and the processor is used for obtaining the polarization information of the single photon according to the polarization parameters.

By adopting the technical scheme, the superconducting nanowire-based single photon polarization detection device and the implementation device thereof have the following beneficial effects:

in an embodiment of the present application, a single photon polarization detection device based on a superconducting nanowire and an implementation apparatus thereof include: a substrate; the pixel layer is arranged on the substrate; the pixel layer comprises one or more super pixel units, and the super pixel units are arranged at equal intervals; the super pixel unit comprises at least four pixel units which are arranged at equal intervals; the pixel units comprise superconductive nanowire structures which are arranged in parallel at equal intervals, the superconductive nanowire structures are sequentially connected end to end, and the angle between the superconductive nanowire structure of each pixel unit in at least four pixel units and the preset direction is different. The superconductive nanowire structure which is arranged in parallel at equal intervals can be used for identifying single photons, and besides the requirement of matching errors between a micro-polaroid and CCD pixels of the existing semiconductor polarization detector and the requirement of uniformity of pixel extinction ratio, at least four pixel units with different angles between the superconductive nanowire structure and the preset direction are directly arranged on the substrate, so that the difficulty of the process can be reduced

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a single photon polarization detection device based on superconducting nanowires provided by an embodiment of the present application;

fig. 2 is a schematic structural diagram of a pixel unit provided in an embodiment of the present application;

FIG. 3 is a schematic cross-sectional view of a substrate according to an embodiment of the present disclosure;

FIG. 4 is a schematic cross-sectional view of a substrate according to an embodiment of the present disclosure;

FIG. 5 is a schematic cross-sectional view of a substrate according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of a superconducting nanowire single photon detection device with a split focal plane according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a free space system-based test optical path provided by an embodiment of the present application;

FIG. 8 is a graph of the count rates of four pixel elements as a function of polarization angle provided by an embodiment of the present application;

FIG. 9 is a diagram illustrating the comparison of the measured values of S1, S2, polarization angle and linear polarization degree with the reference value provided by the embodiment of the present application. (ii) a

FIG. 10 is a detailed comparison graph of measured values and reference values of polarization angles of four pixel elements provided by an embodiment of the application;

the following is a supplementary description of the drawings:

1-a substrate; 2-pixel layer; 21-super pixel unit; 211-picture element unit; 2111-superconducting nanowire structures; 2114-two superconducting nanowire structures connected in parallel; 11-a first silicon dioxide layer; 12-a first silicon layer; 13-a second silicon dioxide layer; 14-insulating dielectric layer; 15-a metal grating layer; 16-a metal mirror layer; 17-a light absorption enhancing structure; 18-a second silicon layer; 61-aspheric collimating lens; 62-linear polarizer; 63-half wave plate; 64-superconducting nanowire single photon detectors with split focal planes; 65-a sensor; 66-a processor; 71-a light source supplying device; 12-a first attenuator; 73-a second attenuator; 74-aspheric collimating lens; 75-linear polarizer; 76-half wave plate; 77-a movable calibration device; 771-polarization detector; 772-power regulating device; 78-noise filtering equipment; 79-superconducting nanowire single photon detector with a split focal plane.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the present application. In the description of the present application, it is to be understood that the terms "upper", "lower", "top", "bottom", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a single photon polarization detection device based on superconducting nanowires according to an embodiment of the present application; as shown in fig. 1, the structure includes: a substrate 1; the pixel layer 2, the pixel layer 2 is set in the substrate 1; the pixel layer 2 comprises one or more super pixel units 21, and the super pixel units 21 are arranged at equal intervals; the super pixel unit 21 comprises at least four pixel units 211, and the at least four pixel units 211 are arranged at equal intervals; the projection areas of the pixel units 211 on a preset plane are the same, the pixel units 211 comprise superconducting nanowire structures 2111 which are arranged in parallel at equal intervals, the superconducting nanowire structures 2111 are sequentially connected end to end, and the angle between the superconducting nanowire structure 2111 of each pixel unit 211 of at least four pixel units 211 and the preset direction is different.

Optionally, at least four pixel elements 211 are regularly arranged according to an array of rows and columns, for example, each row includes N pixel elements 211 arranged at equal intervals, and each column corresponding to N pixel elements 211 includes M pixel elements 211 arranged at equal intervals.

Optionally, the super pixel unit 21 includes four pixel units 211, and angles between the superconducting nanowire structures 2111 of the four pixel units 211 and the preset direction are sequentially different by 45 degrees, which are 0 degree, 45 degrees, 90 degrees, and 135 degrees, respectively. The preset direction may be an X-axis direction or a Y-axis direction in a preset coordinate system.

Optionally, the superconducting nanowire structure includes 1 superconducting nanowire or a plurality of superconducting nanowires arranged in parallel at equal intervals and equal lengths.

The shape of the pixel unit is square, round or triangular.

The superconducting nanowire pair has absorption difference with polarized light in two directions, namely, the direction parallel to the superconducting nanowire and the direction perpendicular to the superconducting nanowire, and polarization extinction ratios of pixel units in at least four pixel units are distributed uniformly.

The super pixel unit comprises four pixel units, and the four pixel units are used for providing optical response counts of polarized light, and the optical response counts of the polarized light are used for jointly solving the polarization state of the linearly polarized light, wherein the polarization state comprises one or more of a polarization angle, a degree of linear polarization (Do L P), a polarization angle (azimuth), an S1 parameter of the linearly polarized light and an S2 parameter of the linearly polarized light.

The superconducting nanowire is in a superconducting state at low temperature, when photons are incident on the nanowire, the photons can be absorbed by the nanowire, and an absorbed area can generate a core hot spot, so that a resistive area can be generated when the superconducting state is damaged, namely a resistor is generated on a non-resistive line, voltage can be generated in the resistive area, but the hot spot can disappear quickly, and energy can be dissipated quickly, so that the voltage is generated instantaneously, the circuit collects the generated pulses, and thus, when the superconducting nanowire forms a conductive circuit, when the single photons pass through, the nanowire senses the pulses, and the passing number of the single photons can be measured by calculating the number of the pulses.

The superconducting nanowire structure 2111 which is arranged in parallel at equal intervals can be used for identifying single photons, and besides the requirement of matching errors between a micro-polarizer and a CCD pixel of the existing semiconductor polarization detector and the requirement of uniformity of pixel extinction ratio is met, at least four pixel units with different angles between the superconducting nanowire structure 2111 and the preset direction are directly arranged on the substrate 1, so that the difficulty of the process can be reduced.

When a circular light spot is projected on a pixel unit, the projected area of a square pixel unit on a preset plane is larger than the projected area of the circular light spot on the preset plane, and a part of the square pixel unit cannot be utilized, which causes waste of unused superconducting nanowires, in order to solve the waste of the unused superconducting nanowires, an optional embodiment is provided, please refer to fig. 2, and fig. 2 is a schematic structural diagram of the pixel unit provided by the embodiment of the present application, as shown in fig. 2:

the pixel unit comprises a plurality of two superconducting nanowire structures 2114 connected in parallel, and the superconducting nanowires in the same two superconducting nanowire structures 2114 connected in parallel have the same length;

the plurality of two parallel superconducting nanowire structures 2114 are sequentially connected end to end, the lengths of the superconducting nanowires in the two different parallel superconducting nanowire structures 2114 are sequentially and incrementally increased along the direction A perpendicular to the superconducting nanowires, the superconducting nanowires are sequentially and incrementally decreased after preset positions, and the superconducting nanowires in the pixel unit are symmetrically arranged relative to the preset positions.

The outline formed by the edges of the superconducting nanowires in the pixel unit is approximately circular.

Compared with the strict matching requirement between the micro-polarizer and the CCD pixel of the existing semiconductor polarization detector, the embodiment of the application provides three substrates which do not need the strict matching requirement.

Referring to fig. 3, fig. 3 is a schematic cross-sectional structure diagram of a substrate according to an embodiment of the present application, as shown in fig. 3:

the substrate comprises a first silicon dioxide layer 11, a first silicon layer 12 and a second silicon dioxide layer 13; the first silicon dioxide layer 11, the first silicon layer 12, and the second silicon dioxide layer 13 are sequentially stacked.

Optionally, the thickness of the first silicon dioxide layer 11 is 268 nm, the thickness of the first silicon layer 12 is 400 μm, and the thickness of the second silicon dioxide layer 13 is 268 nm. The pixel layer 2 is disposed on the first silicon dioxide layer 11 or the second silicon dioxide layer 13. The substrate structure is typically the device where light is incident from the pixel layer to the substrate.

Referring to fig. 4, fig. 4 is a schematic cross-sectional structure diagram of a substrate according to an embodiment of the present application, as shown in fig. 4:

on the basis of the substrate structure of the first optional embodiment, the substrate further comprises an insulating medium layer 14, a metal grating layer 15 and a metal mirror layer 16; the insulating medium layer 14 is arranged on the first silicon dioxide layer 11; the image element layer 2 and the metal grating layer 15 are arranged in the insulating medium layer 14 at intervals; the metal grating layer 15 is disposed above the spacing portion of the superconducting nanowires; the metal reflector layer 15 is disposed on the surface of the insulating medium layer 14 close to the metal grating layer 15. The substrate structure can effectively improve the polarization extinction ratio PER (polarization extinction ratio) of the device, thereby improving the sensitivity of polarization detection. The superconducting nanowire and the metal grating layer 15 are both conductive, so the insulating medium layer 14 is required to isolate the superconducting nanowire from the metal grating layer 15. Alternatively, the material of the insulating dielectric layer 14 may be silicon monoxide or silicon dioxide.

The metal grating layer 15 comprises a plurality of metal gratings which are arranged at equal intervals, and the metal gratings correspond to the interval parts of the superconducting nanowires one by one; the metal grating is disposed above the spacing portion of the superconducting nanowires.

Optionally, the metal mirror layer 16 includes a gold mirror layer or a silver mirror layer.

Optionally, the thickness of the insulating dielectric layer 14 is 200 nm, and the thickness of the metal mirror layer 16 is 200 nm.

In a third alternative implementation manner, please refer to fig. 5, fig. 5 is a schematic cross-sectional structure diagram of a substrate according to an embodiment of the present application, as shown in fig. 5:

the substrate comprises a light absorption enhancing structure 17 and a second silicon layer 18; the light absorption enhancement structure 17 is disposed on the second silicon layer 18; the light absorption enhancing structure 17 includes at least two layers of dielectric material stacked in sequence, and the two layers of dielectric material include two layers of material with different refractive indexes stacked in sequence. Optionally, the metal grating layer is made of aluminum.

Optionally, the light absorption enhancing structure 17 is used to achieve absorption enhancement of a specific wavelength band or bands. For example: SiO consisting of 15 periodic stacks₂/Ta₂O₅The DBR high-reflection structure formed by the double-layer dielectric material can effectively enhance the absorption of a device in a 1550nm waveband, the superconductive nanowire prepared on the substrate can keep the polarization detection capability and simultaneously has high detection efficiency, and the substrate structure is generally a device with light incident from a pixel layer to the substrate.

Optionally, the superconducting nanowire is made of niobium nitride.

On the other hand, an embodiment of the present application provides an implementation apparatus for single photon polarization detection based on superconducting nanowires, please refer to fig. 6, where fig. 6 is a schematic structural diagram of a superconducting nanowire single photon detection apparatus with a split focal plane according to an embodiment of the present application; as shown in fig. 6, the apparatus includes:

an aspheric collimating lens 61, a linear polarizer 62, a half-wave plate 63, a superconducting nanowire single photon detector 64 with a split focal plane, a sensor 65 and a processor 66; the aspheric collimating lens 61, the linear polarizer 62, the half-wave plate 63 and the superconducting nanowire single-photon detector 64 with the split focal plane are sequentially arranged at intervals;

the superconducting nanowire single photon detector 64 with a split focal plane comprises a superconducting nanowire-based single photon polarization detection device as described above;

the sensor 65 is used for detecting the polarization parameters of a single photon in a free space sequentially through the aspheric collimating lens 61, the linear polarizer 62, the half-wave plate 63 and the superconducting nanowire single photon detector 64 with a split focal plane under a preset condition; the processor 66 is used for obtaining the polarization information of the single photon according to the polarization parameters. The linearly polarizing plate 62 is used to output linearly polarized light, and the half-wave plate 63 is used to control the polarization angle change of the linearly polarized light. Optionally, the polarization parameter may be the number of photons of four pixel units, which are respectively 0 degree, 45 degrees, 90 degrees and 135 degrees, of the polarized light sequentially differing by 45 degrees from the angle between the superconducting nanowire and the preset direction in the preset time period, and the polarization information is the polarization angle of the incident light.

FIG. 7 is a schematic diagram illustrating a test effect of a test optical path based on a free space system according to an embodiment of the present application; as shown in fig. 7:

the light emitted by the light source supply device 71 is transmitted to the first attenuator 72 through the SMF fiber for attenuation, and then transmitted to the second attenuator 73 for attenuation, so as to generate single photons, the single photons are transmitted to the linear polarizer 75 through the aspheric collimating lens 74 to form linearly polarized light, and then the linearly polarized light with a preset polarization angle is output through the half-wave plate 76, the linearly polarized light measures reference values such as the polarization angles S1 and S2 and the linear polarization degree of the linearly polarized light through the polarization detector 771 in the movable calibration device 77, and the power adjustment device 772 is used for ensuring the preset intensity of the linearly polarized light transmitted to the polarization detector 771. After the movable calibration device 77 is removed, the linearly polarized light is filtered to remove background noise through the noise filtering device 78, and then is transmitted to the superconducting nanowire single photon detector 79 with a sub-focal plane, and then the number of photons passing through the pixel unit of the superconducting nanowire single photon detector 79 with the sub-focal plane in a preset time period is detected by the sensor. For example, the method for measuring the polarization angle Azimuth includes the following steps that the superconducting pixel unit comprises four pixel units, and the angles between the superconducting nanowires of the four pixel units and the preset direction sequentially differ by 45 degrees, namely 0 degree, 45 degrees, 90 degrees and 135 degrees: in order to ensure the consistency of the polarization state of the incident photons with the final arrival at the device, an own spatial light path is required. The optical path can also use a semiconductor polarization detector to monitor the polarization state of incident light in real time when the light intensity is high. During measurement, a saturation bias point (intrinsic efficiency 100%) of each pixel is selected for measurement, a sine curve of light counts of four pixel units changing along with a polarization angle is obtained, and the sine curve is divided by the maximum count respectively for normalization processing to eliminate coupling difference. Substituting the following formula:

calculating the polarization angle Azimuth, PCR of the incident light_0°、PCR_45°、PCR_90°、PCR_135°The number of photons of four pixel units of which the phase difference is 45 degrees, namely 0 degree, 45 degrees, 90 degrees and 135 degrees, sequentially passes through the angle between the superconducting nanowire and the preset direction in a preset time period.

Referring to fig. 8, fig. 8 is a graph illustrating a variation of the count rates of four pixel units with a polarization angle according to an embodiment of the present application; taking four pixel units as an example, fig. 8 shows a sine curve graph of the counting rate of the superconducting nanowire-based single-photon polarization detection device changing with the polarization angle of incident light, which shows the polarization sensitivity of the superconducting nanowire, and phase information, i.e., polarization angle information, of linearly polarized light can be extracted through data analysis of the four curves.

Fig. 9 is a schematic diagram of comparison between measured values of S1 and S2, a polarization angle, and a linear polarization degree, and a reference value, which are provided in the embodiment of the present application, and taking four pixel units as an example, fig. 9 shows a polarization detection effect of a single photon polarization detection device based on a superconducting nanowire provided in the embodiment of the present application, and the comparison between the measured values and the reference values of linear polarized light under multiple measurements has good linearity, and the reference values of linear polarized light are detected by a polarization detector with higher detection accuracy, which takes the linear polarization degree (Do L P), the polarization angle (azimuth), the S1 parameter, and the S2 parameter as examination indexes.

FIG. 10 is a detailed comparison graph of measured values and reference values of polarization angles of four pixel elements provided by an embodiment of the application; taking four pixel units as an example, fig. 9 shows a detailed comparison graph of a linear polarization angle detection value and a reference value of a superconducting nanowire-based single photon polarization detection device provided by the embodiment of the application, and it can be seen that the matching of the two has good linearity, the control deviation is within 4 degrees, and the single photon detection capability is provided.

The application relates to a single photon polarization detection device based on a superconducting nanowire and an implementation device thereof, wherein the device structure comprises: a substrate; the pixel layer is arranged on the substrate; the pixel layer comprises one or more super pixel units, and the super pixel units are arranged at equal intervals; the super pixel unit comprises at least four pixel units which are arranged at equal intervals; the projection areas of the pixel units on a preset plane are the same; the pixel units comprise superconducting nanowire structures which are arranged in parallel at equal intervals, the superconducting nanowire structures are sequentially connected end to end, and the angle of the superconducting nanowire structure in the parallel direction of each pixel unit in at least four pixel units is different; and the nano-wire has obvious absorption difference (namely, the polarization extinction ratio is larger, the better) to the polarized light which is parallel to the nano-wire and is vertical to the two directions of the nano-wire. The polarization state detection of the linearly polarized light can be realized by measuring the light response count of the four super-pixels to the polarization angle of the polarized light. Compared with the existing semiconductor polarization detector (such as a CCD polarization detector based on a micro-polarizer), the superconducting nanowire structure can realize the dual functions of a linear polarizer and a photon detector and has single photon level sensitivity. On the basis of the structure of the invention, different substrates can be replaced according to application requirements, and multilayer media or metal can be integrated on the top of the nanowire, so that the device has higher polarization ratio and detection efficiency. The invention integrates the advantages of the single photon detector with the superconducting nanowire structure, has the characteristics of expandable device scale, simple structure and the like, and is expected to play a role in the fields of polarization detection and imaging, quantum communication, astronomical observation, remote sensing and the like in a weak light environment.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.