Sensing system and design method of sensing system

Abstract

The invention provides a sensing system and a design method of the sensing system.The sensing system comprises a light source, an interference device and a detection module which are arranged in the light path transmission direction, the interference device is configured to be a metasurface and comprises a first modulation unit and a second modulation unit, and the detection module comprises a detector used for sensing light signals. After the interference device modulates the emergent light of the light source, the emergent light of the two modulation units has a phase difference and is transmitted to the detector; the sensing system modulates the emergent light of the light source, so that the emergent light of the two modulation units has a phase difference, after the emergent light of the two modulation units is transmitted to the detector, parameter measurement can be performed by using the light intensity change sensed by the detector, and an interference device adopts a metasurface with a sub-wavelength size, so that the measurement precision is improved. The size of the sensing system can be reduced, and miniaturization is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of sensing, and in particular to a sensing system and a design method of the sensing system. Background Art

[0002] The sensing system is a system based on the principle of interference. By using the sensing system, various parameters (such as environmental parameters, etc.) can be measured. Existing sensing systems usually use traditional optical elements as interference devices, which results in a large volume of the sensing system, which is not conducive to miniaturization. Summary of the invention

[0003] The object of the present invention is to provide a sensor system and a design method of the sensor system which are conducive to miniaturization.

[0004] To achieve one of the above-mentioned purposes of the invention, one embodiment of the present invention provides a sensing system, comprising a light source, an interference device and a detection module arranged along the transmission direction of the optical path, the interference device being configured as a metasurface and comprising a first modulation unit and a second modulation unit, the detection module comprising a detector for sensing optical signals, and after the interference device modulates the output light of the light source, the output light of the two modulation units has a phase difference and is transmitted to the detector.

[0005] As a further improvement of an embodiment of the present invention, the light source and the detection module are located on the same side of the interference device;

[0006] Alternatively, the light source and the detection module are located on opposite sides of the interference device.

[0007] As a further improvement of an embodiment of the present invention, the metasurface includes a substrate, and the first modulation unit and the second modulation unit use the same substrate;

[0008] Alternatively, the first modulation unit and the second modulation unit respectively use separate substrates.

[0009] As a further improvement of an embodiment of the present invention, the interference device and the light source are arranged along the optical axis, and / or the interference device and the detection module are arranged along the optical axis.

[0010] As a further improvement of an embodiment of the present invention, the output light of the light source is coherent light.

[0011] As a further improvement of an embodiment of the present invention, the first modulation unit and the second modulation unit are both configured as gratings or super lenses;

[0012] Alternatively, the first modulation unit is configured as a superlens, and the second modulation unit is configured as a grating.

[0013] As a further improvement of one embodiment of the present invention, at least one modulation unit in the interference device is configured as a superlens, and the distance between the at least one modulation unit and the detection module along the optical axis is not greater than the modulation focal length of the at least one modulation unit.

[0014] As a further improvement of an embodiment of the present invention, the interference device further includes a partition located between the first modulation unit and the second modulation unit, and the partition is configured to transmit the target band light of the interference device.

[0015] As a further improvement of an embodiment of the present invention, the metasurface includes a substrate, and the substrate of the first modulation unit and / or the second modulation unit is made of elastic material.

[0016] As a further improvement of an embodiment of the present invention, the interference device further includes a deformation layer wrapped around the first modulation unit and / or the second modulation unit, and the deformation layer is made of a thermal expansion material.

[0017] As a further improvement of one embodiment of the present invention, the detection module includes a first optical waveguide and a second optical waveguide, the first optical waveguide is configured to transmit the output light of the first modulation unit to the detector, and the second optical waveguide is configured to transmit the output light of the second modulation unit to the detector, and there is a phase difference between the output lights of the two optical waveguides.

[0018] As a further improvement of an embodiment of the present invention, the first optical waveguide and / or the second optical waveguide is configured as a grating waveguide, a photonic crystal waveguide, an optical waveguide with a free shape, or a supersurface waveguide.

[0019] As a further improvement of an embodiment of the present invention, a sensing structure is provided on the first optical waveguide, and the refractive index of the sensing structure changes with changes in environmental parameters.

[0020] As a further improvement of an embodiment of the present invention, a refractive index adjustable structure is provided on the first optical waveguide to adjust the phase difference between the output lights of the two optical waveguides.

[0021] To achieve one of the purposes of the above invention, the present invention further provides a design method of a sensor system, the design method of the sensor system is applicable to the above sensor system, and the design method comprises:

[0022] According to the parameters to be measured of the sensing system, design interference devices and / or detection modules accordingly;

[0023] Utilize specific pixels of the detector to sense the light intensity of different parameters to be measured, and obtain the change relationship between the parameter to be measured and the light intensity corresponding to the specific pixels;

[0024] Select any parameter to be measured as a calibration parameter, and use the calibration parameter as a reference value when measuring the sensor system.

[0025] As a further improvement of an embodiment of the present invention, the first modulation unit and / or the second modulation unit are designed accordingly according to the parameters to be measured of the sensing system.

[0026] As a further improvement of an embodiment of the present invention, at least two specific pixels are selected, and the variation relationship between the parameters to be measured and the light intensity corresponding to the at least two specific pixels is obtained.

[0027] As a further improvement of an embodiment of the present invention, the parameter to be measured is configured as the refractive index of the environment in which the interference device is located, the pressure exerted on the interference device, or the temperature of the environment in which the interference device is located.

[0028] As a further improvement of one embodiment of the present invention, when the parameter to be measured is configured as the refractive index of the environment in which the interference device is located, the change in the fluid density of the environment in which the interference device is located, the change in the humidity of the environment in which the interference device is located, or the change in the temperature of the environment in which the interference device is located is determined based on the change in the refractive index of the environment in which the interference device is located.

[0029] As a further improvement of an embodiment of the present invention, the detection module includes a first optical waveguide and a second optical waveguide, and the first optical waveguide and / or the second optical waveguide are designed accordingly according to the parameters to be measured of the sensing system.

[0030] Compared with the prior art, in the embodiments of the present invention, the sensing system modulates the outgoing light of the light source so that there is a phase difference between the outgoing light of the two modulation units. After the outgoing light of the two modulation units is transmitted to the detector, the light intensity change sensed by the detector can be used to measure parameters. Moreover, the interference device adopts a sub-wavelength-sized metasurface, which can reduce the volume of the sensing system and is conducive to miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the optical path of the sensing system in some preferred embodiments of the present invention, wherein the light source and the detection module are located on opposite sides of the interference device;

[0032] Figure 2 is a schematic diagram of the optical path of the sensing system in some preferred embodiments of the present invention, wherein the light source and the detection module are located on the same side of the interference device;

[0033] Figure 3 yes Figure 2 A first preferred embodiment of the embodiment in the embodiment;

[0034] Figure 4 yes Figure 3 A plurality of examples of a top view of any modulation unit in;

[0035] Figure 5 yes Figure 2 A second preferred embodiment of the embodiment in the embodiment;

[0036] Figure 6 yes Figure 2 A third preferred embodiment of the embodiment;

[0037] Figure 7 Schematic diagram of the optical path of the sensing system in some other preferred embodiments of the present invention;

[0038] Figure 8 yes Figure 7 An implementation method of the detection module;

[0039] Figures 9 to 11 yes Figure 7 Multiple implementations of the detection module;

[0040] Fig.12 yes Figure 7 Another implementation of the detection module;

[0041] Fig.13 yes Figure 7 Another implementation method of the detection module;

[0042] Fig.14 Is adopted Fig. 9 The corresponding relationship between the environmental refractive index and the detector power when the detection module in the sensor system constitutes a sensor system;

[0043] Fig.15 yes Figure 3 The corresponding light spot diagram on the detector before the sensing system performs measurement and the light intensity distribution diagram at x=0 on the detector;

[0044] Fig.16 yes Figure 3 The corresponding light spot diagram on the detector after the middle sensing system measures and the light intensity distribution diagram at x=0 on the detector;

[0045] Fig.17 yes Figure 3 The relationship between the deflection angle of the two modulation units of the sensing system and the ambient refractive index;

[0046] Fig.18 yes Figure 3 A graph showing the relationship between the coherent irradiance sensed by two specific pixels of the sensing system and the ambient refractive index;

[0047] Fig.19 yes Figure 3A graph showing the relationship between the coherent irradiance sensed by two specific pixels and the ambient refractive index when the sensing system detects the pressure, wherein the first modulation unit and the second modulation unit are both subjected to the same pressure;

[0048] Fig. 20 yes Figure 3 A graph showing the relationship between the coherent irradiance sensed by two specific pixels and the ambient refractive index when the sensing system detects pressure, wherein the first modulation unit is subjected to pressure;

[0049] Fig.21 yes Figure 5 The corresponding light spot diagram on the detector before the sensing system performs measurement and the light intensity distribution diagram at x=0 on the detector;

[0050] Fig. 22 yes Figure 5 The corresponding light spot diagram on the detector and the light intensity distribution diagram at x=0 on the detector after the sensing system performs measurement, where only the refractive index of the environment where one modulation unit is located is changed;

[0051] Fig.23 yes Figure 5 The corresponding light spot diagram on the detector and the light intensity distribution diagram at x=0 on the detector after the sensing system performs measurement, wherein the refractive index of the environment where the two modulation units are located is changed;

[0052] Fig.24 yes Figure 6 The corresponding light spot diagram on the detector before the middle sensing system performs measurement and the light intensity distribution diagram at y=0 on the detector;

[0053] Fig.25 yes Figure 6 The corresponding light spot diagram on the detector and the light intensity distribution diagram at y=0 on the detector after the sensing system performs measurement, where only the refractive index of the environment where one modulation unit is located is changed;

[0054] Fig.26 yes Figure 6 The corresponding light spot diagram on the detector and the light intensity distribution diagram at y=0 on the detector after the sensing system performs measurement, wherein the refractive index of the environment in which the two modulation units are located is changed. DETAILED DESCRIPTION

[0055] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0056] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0057] Furthermore, it should be understood that although the terms first, second, etc. may be used to describe various elements or structures in this article, these described objects should not be limited by the above terms. The above terms are only used to distinguish these described objects from each other. For example, the first modulation unit can be called the second modulation unit, and similarly, the second modulation unit can also be called the first modulation unit, which does not deviate from the scope of protection of this application.

[0058] In various drawings of the present invention, for the convenience of illustration, some sizes of structures or parts are exaggerated relative to other structures or parts, and thus, only the basic structure of the subject matter of the present invention is illustrated.

[0059] refer to Figures 1 to 6 As shown, some preferred embodiments of the present invention provide a sensing system, in which the outgoing light of the two modulation units (201, 202) of the interference device 20 is directly incident when transmitted to the detector 301, that is, the outgoing light of the two modulation units (201, 202) is directly incident on the detector 301, so as to be directly sensed by the detector 301, which can simplify the sensing system.

[0060] Specifically, refer to Figure 1 As shown, a sensing system includes a light source 10, an interference device 20 and a detection module 30 arranged along the transmission direction of the optical path. In this embodiment, the interference device 20 is located on the light-emitting side of the light source 10, and is used to receive the emitted light of the light source 10. The detection module 30 is located on the light-emitting side of the interference device 20, and is used to receive the emitted light of the interference device 20.

[0061] Specifically, the detection module 30 includes a detector 301 for sensing the optical signal. In this embodiment, the detection module 30 is preferably composed only of the detector 301. After the output light of the light source 10 is modulated (e.g., phase modulated) by the interference device 20, it is emitted to the detection module 30 (i.e., the detector 301). The detector 301 can convert the received optical signal into an electrical signal, and then obtain the corresponding light intensity value.

[0062] Furthermore, the interference device 20 is configured as a metasurface. In this embodiment, a metasurface refers to an artificial layered material whose size is less than or approximately equal to the wavelength, which can be regarded as the two-dimensional counterpart of a metamaterial. The metasurface can control the polarization, phase, amplitude, frequency, propagation mode and other characteristics of electromagnetic waves through the surface sub-wavelength superstructure unit, and realize beam shaping, beam deflection, superlens, super holography, optical rotation, anti-reflection and anti-reflection, and other characteristics.

[0063] Moreover, the metasurface is an optical element of sub-wavelength size, which is suitable for the current micrometer-scale detector 301. At the same time, its preparation process is compatible with mature semiconductor sensor technology and has strong practicality and economy.

[0064] Specifically, the super surface includes a plurality of super structure units arranged in an array, and a nano structure is provided at the center and / or vertex position of each super structure unit. The super structure unit is obtained by dividing the super surface to obtain a structure unit centered on each nano structure. A plurality of nano structures are arranged on a substrate, wherein the nano structures in each period constitute a super structure unit. The super structure unit is a densely packed figure, such as a regular quadrilateral, a regular hexagon, a fan, etc., each period contains a nano structure, and the vertex and / or center of the super structure unit can be provided with a nano structure. In the case where the super structure unit is a regular hexagon, at least one nano structure is provided at each vertex and center position of the regular hexagon. Similarly, the same is true in the case of a fan and a square.

[0065] Specifically, the nanostructure is configured as a polarization-dependent structure or a polarization-independent structure. The nanostructure can select a polarization-dependent structure or a polarization-independent structure according to different usage scenarios. Polarization-independent structures include, for example, cylindrical shapes, square cylindrical shapes, cross cylindrical shapes, and square cylindrical shapes with round holes. Polarization-dependent structures include, for example, elliptical cylindrical shapes, rectangular cylindrical shapes, and hexagonal prism shapes. The nanostructure can be a positive structure or a negative structure. For example, the shape of the nanostructure includes a cylindrical shape, a hollow cylindrical shape, a square prism, a hollow square prism, and the like.

[0066] Among them, the substrate can be made of a translucent or opaque material. When the substrate transmits light (i.e., transmits the target band light), a transmissive metasurface is formed. When the substrate is opaque or reflects light (i.e., does not transmit or reflects the target band light), it is a reflective metasurface. The material of the nanostructure can be a material with low loss in the working band, such as silicon, silicon nitride, titanium dioxide, etc., or a metal material such as copper, aluminum, gold, silver, etc. An adhesion layer can be added between the substrate and the nanostructure to increase the process stability of the nanostructure. The adhesion layer can be ITO, aluminum oxide, etc.

[0067] Specifically, the interference device 20 includes a first modulation unit 201 and a second modulation unit 202. In this embodiment, the first modulation unit 201 and the second modulation unit 202 are both optical elements based on a metasurface, similar to the interference device 20. Preferably, the first modulation unit 201 and the second modulation unit 202 are located in the same plane (e.g., a plane perpendicular to the optical axis), thereby reducing the occupied space of the interference device 20.

[0068] It can be foreseen that, compared with traditional optical elements, the interference device 20 based on the metasurface can adjust any dimension of the electromagnetic wave phase, polarization, amplitude, etc., and realize diversified functions such as abnormal deflection and focusing.

[0069] Moreover, the metasurface uses traditional photolithography technology, which is lower in cost than traditional lenses, smaller in size, and more integrated. The nanostructure is etched on the planar optical medium through a detector-compatible process, and the incident light is emitted to any position at any divergence angle using the interference device 20 based on the metasurface, so that the detector 301 and the light source 10 are integrated on the planar optical medium (that is, both are located on a plane perpendicular to the optical axis), further saving the size in the direction of the optical axis, realizing the high integration and miniaturization of the sensing system, and reducing the cost and volume of the entire system.

[0070] In addition, the special design of the nanostructure in the metasurface can realize the control of the arbitrary divergence angle and direction of the light beam, so that the metasurface with a planar structure can meet the modulation needs of the incident light without controlling a special assembly angle, greatly reducing the number of optical elements in the interference device 20 and the difficulty of assembly, and at the same time compressing the optical path.

[0071] Furthermore, after the interference device 20 modulates the emitted light of the light source 10, the emitted light of the two modulation units (201, 202) has a phase difference, and both are transmitted to the detector 301. In this embodiment, since the first modulation unit 201 and the second modulation unit 202 are located in different spatial positions, the emitted light of the two modulation units (201, 202) has a phase difference. When the emitted light of the two modulation units (201, 202) of the interference device 20 is transmitted to the detector 301, a direct incident mode is adopted, that is, the emitted light of the two modulation units (201, 202) is directly incident to the detector 301, so as to be directly sensed by the detector 301, which can simplify the sensing system.

[0072] Specifically, after modulating the outgoing light of the light source 10, each modulation unit (201, 202) of the interference device 20 emits light to the same area of ​​the detection module 30 (i.e., the detector 301), and forms an interference pattern on the detection module 30 (i.e., the detector 301). After the first modulation unit 201 and the second modulation unit 202 modulate the outgoing light of the light source 10, they emit light to the same area (i.e., the same position, such as the same pixel / specific pixel of the detector 301) of the detection module 30 (i.e., the detector 301). Since there is a phase difference between the two outgoing light beams of the first modulation unit 201 and the second modulation unit 202, and the phase difference is constant, an interference pattern, such as light and dark interlaced interference fringes, can be formed on the detection module 30 (i.e., the detector 301). After the interference pattern is sensed by the corresponding pixel (e.g., a specific pixel) on the detector 301, it can be converted into a corresponding light intensity value.

[0073] When the refractive index of the environment in which the interference device 20 (for example, the first modulation unit 201 and / or the second modulation unit 202) is located changes (for example, the fluid density, humidity or temperature of the environment changes), or the exit angle and / or the incident angle caused by other sensing parameters (for example, elastic deformation caused by external force) changes, the phase difference of the light emitted by the two modulation units (201, 202) will change, that is, the interference pattern will change or the interference pattern will be displaced on the detection module 30. When the phase difference changes, that is, the interference pattern changes or the interference pattern is displaced on the detection module 30, after being sensed by the corresponding pixels on the detector 301 and converted into corresponding light intensity values, the refractive index or other sensing parameters of the environment to be measured can be determined by comparing the changes in the light intensity values ​​before and after the measurement, thereby achieving the measurement of the parameters to be measured.

[0074] Specifically, the emitted light of the light source 10 is coherent light. In the present embodiment, the light source 10 can be configured as a VCSE l or a laser light source, as long as the emitted light is coherent light, thereby generating interference of coherent light to form an interference pattern. The morphology of the emitted light of the light source 10 can be collimated light or divergent light, both of which can be arbitrarily modulated by the interference device 20 and then emitted to the detection module 30 (i.e., the detector 301). The detector 301 can be a CMOS, etc., and preferably a detector with higher sensitivity is selected according to different working bands.

[0075] Furthermore, the light source 10 and the detection module 30 (ie, the detector 301) are respectively located on opposite sides of the interference device 20. In this embodiment, the substrate of the interference device 20 transmits light in the working band, and the interference device 20 is configured as a transmissive metasurface.

[0076] Specifically, Figure 1As shown in a, the interference device 20 and the light source 10 are arranged along the optical axis, and the interference device 20 and the detection module 30 (i.e., the detector 301) are arranged along the optical axis. In this embodiment, the light source 10, the interference device 20, and the detection module 30 (i.e., the detector 301) are arranged along the optical axis (Z axis in the figure), so as to reduce the volume of the sensing system along the X-axis and Y-axis directions, so that the sensing system meets different usage scenarios. In addition, when the interference device 20 and the light source 10 are arranged along the optical axis, it is possible to ensure that the incident angle of the incident light is small, which can improve the efficiency of the metasurface compared to the solution with a larger incident angle. In addition, when the interference device 20 and the detection module 30 (i.e., the detector 301) are arranged along the optical axis, the optical path between the two can be shortened.

[0077] Specifically, Figure 1 As shown in b, the interference device 20 and the light source 10 are arranged along the optical axis, and the arrangement direction of the interference device 20 and the detection module 30 (i.e., the detector 301) is at a certain angle to the optical axis, so that the sensing system can meet different usage scenarios.

[0078] Specifically, Figure 1 As shown in c, the interference device 20 and the detection module 30 (i.e., the detector 301) are arranged along the optical axis, and the arrangement direction of the interference device 20 and the light source 10 is at a certain angle to the optical axis, so that the sensing system can meet different usage scenarios.

[0079] Mate Reference Figure 2 As shown, further, the light source 10 and the detection module 30 (i.e., the detector 301) are located on the same side of the interference device 20. In this embodiment, the substrate of the interference device 20 reflects the light in the working band, and the interference device 20 is configured as a reflective metasurface. The substrate of the reflective metasurface can be a highly reflective metal material, such as copper, aluminum, gold, silver, etc. When the interference device 20 adopts a reflective metasurface, the optical path can be folded, thereby reducing the volume of the sensing system along the optical axis (i.e., the Z axis).

[0080] Through the special design of the nanostructure in the metasurface, it is possible to achieve arbitrary divergence angle and direction control of the light beam, thereby meeting the arbitrary assembly angle requirements of the interference device 20 in the sensing system. Even if the light source 10, the interference device 20, and the detection module 30 (i.e., the detector 301) are not in any plane (such as the XY plane, the XZ plane, and the YZ plane), it can still be achieved by designing the nanostructure in the interference device 20 and forming a corresponding interference pattern. Moreover, the implementation method is easier than that of a traditional lens, and the effect is better.

[0081] Specifically, Figure 2As shown in a, the interference device 20 and the light source 10 are arranged along the optical axis, and the arrangement direction of the interference device 20 and the detection module 30 (i.e., the detector 301) is at a certain angle to the optical axis. In this embodiment, when the interference device 20 and the light source 10 are arranged along the optical axis, it is possible to ensure that the incident angle of the incident light is small, which can improve the efficiency of the metasurface compared to the solution with a larger incident angle. The interference device 20 is not arranged along the optical axis with the detection module 30 (i.e., the detector 301), which can avoid the blocking of light when the detection module 30 (i.e., the detector 301) and the light source 10 overlap along the optical axis.

[0082] Specifically, Figure 2 As shown in FIG. 1 , the interference device 20 and the detection module 30 (i.e., the detector 301) are arranged along the optical axis, and the arrangement direction of the interference device 20 and the light source 10 is at a certain angle to the optical axis. In this embodiment, when the interference device 20 and the detection module 30 (i.e., the detector 301) are arranged along the optical axis, the optical path between the two can be shortened. The interference device 20 is not arranged along the optical axis with the light source 10, which can avoid the blocking of light when the detection module 30 (i.e., the detector 301) and the light source 10 overlap along the optical axis.

[0083] Continue with reference Figure 1 and Figure 2 As shown, the first modulation unit 201 and the second modulation unit 202 use the same substrate. In this embodiment, the first modulation unit 201 and the second modulation unit 202 are respectively used as a part (or a region) of the interference device 20. The first modulation unit 201 and the second modulation unit 202 can share a substrate, that is, the interference device 20 is designed and manufactured as a metasurface as a whole, thereby eliminating the need for assembly between the first modulation unit 201 and the second modulation unit 202.

[0084] Mate Reference Figure 3 As shown, the first modulation unit 201 and the second modulation unit 202 use separate substrates, respectively. In this embodiment, the first modulation unit 201 and the second modulation unit 202 each use a separate substrate, that is, the first modulation unit 201 and the second modulation unit 202 are designed and manufactured separately, and then the interference device 20 is composed of two separate metasurface structure modulation units. This method can improve the degree of freedom in the design of the first modulation unit 201 and the second modulation unit 202, that is, the first modulation unit 201 and the second modulation unit 202 can use substrates and / or nanostructures of different materials to meet the different use requirements of the interference device 20.

[0085] For ease of description, the following description of the sensing system is an exemplary description based on the technical solution of "the light source 10 and the detection module 30 (i.e., the detector 301) are located on the same side of the interference device 20". The technical solution of "the light source 10 and the detection module 30 (i.e., the detector 301) are located on opposite sides of the interference device 20" can also realize the concept of the present invention.

[0086] Continue with reference Figure 3 As shown, a sensing system provided by a preferred first embodiment of the present invention has a relatively simple design and structure of the interference device 20 because both the first modulation unit 201 and the second modulation unit 202 are configured as gratings.

[0087] Specifically, the first modulation unit 201 and the second modulation unit 202 are both configured as gratings. In this embodiment, the first modulation unit 201 and the second modulation unit 202 can deflect the emitted light of the light source 10, such as deflection of a two-dimensional light beam, and the light beam is accurately emitted to the same area of ​​the detection module 30 (i.e., the detector 301) after deflection, thereby forming an interference pattern.

[0088] Mate Reference Figure 4 As shown, when the first modulation unit 201 and the second modulation unit 202 are both configured as gratings, from the top view thereof, they can be equidistant line gratings (such as Figure 4 a) Supergratings with unequal spacing (such as Figure 4 b) or other forms of gratings based on metasurfaces (such as Figure 4 c and 4d).

[0089] Specifically, when the light source 10 emits collimated light, or the incident light of the interference device 20 is collimated light (for example, vertically incident collimated light), the phase distribution of the interference device 20 at least satisfies:

[0090]

[0091] Among them, θ r is the reflection angle, θ i is the angle of incidence, λ0 is the vacuum wavelength, n i is the refractive index of the environment in which the metasurface is located, is the phase gradient of the metasurface.

[0092] Furthermore, the interference device 20 further includes a partition 203 located between the first modulation unit 201 and the second modulation unit 202. In this embodiment, the partition 203 blocks the first modulation unit 201 and the second modulation unit 202, for example, blocks heat exchange and fluid flow between the first modulation unit 201 and the second modulation unit 202. Thus, the environmental parameters of the first modulation unit 201 and the second modulation unit 202 can be changed separately, for example, the temperature, humidity, fluid density, etc. of the environment in which the first modulation unit 201 and / or the second modulation unit 202 are located can be changed separately.

[0093] Furthermore, the partition 203 is configured to transmit the target band light of the interference device 20. In this embodiment, the target band light can pass through the partition 203, so that the partition 203 does not block the outgoing light of the light source 10, so that the first modulation unit 201 and the second modulation unit 202 can smoothly receive the outgoing light of the light source 10.

[0094] Then, by setting a partition 203 between the first modulation unit 201 and the second modulation unit 202, the environmental parameters of any modulation unit (201, 202), such as temperature, humidity, and fluid density, can be changed individually, thereby changing the interference pattern accordingly. Moreover, the interference pattern can be changed by only changing the environmental parameters of at least one modulation unit (201, 202) in the interference device 20.

[0095] Furthermore, the substrate of the first modulation unit 201 and / or the second modulation unit 202 is made of elastic material. In this embodiment, the substrate made of elastic material can be used to measure pressure, that is, a certain pressure is applied to the substrate of the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202), and the elastic deformation of the substrate will cause the divergence of the exit angle of the reflected parallel light. By detecting the change of the interference pattern, the pressure information (i.e., the change of pressure) can be obtained. Among them, the substrate can be made of a material with a large elastic modulus and yield strength. Moreover, the change of the interference pattern can be achieved by only using an elastic material for at least one modulation unit (201, 202) in the interference device 20.

[0096] Furthermore, the interference device 20 also includes a deformation layer wrapped in the first modulation unit 201 and / or the second modulation unit 202, and the deformation layer is made of a thermal expansion material. In this embodiment, by wrapping the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) in the deformation layer, the deformation layer is made of a material with a large thermal expansion coefficient, and the change in temperature will cause the expansion change at the exit interface, thereby causing the phase difference between the exit lights of the two modulation units (201, 202) to change, that is, causing different degrees of phase change of the two interference lights on the detector 301, and the temperature value (i.e., the change in temperature) can be obtained by detecting the change in the interference pattern. Moreover, the change in the interference pattern can be achieved by only wrapping at least one modulation unit (201, 202) in the interference device 20 in the deformation layer.

[0097] refer to Figure 5 As shown, a preferred second embodiment of the present invention provides a sensing system, in which the first modulation unit 201 and the second modulation unit 202 are both configured as a super lens, so that more pixels on the detector 301 can sense the light intensity of the interference pattern. In this embodiment, the same reference numerals represent the same elements with similar functions and are not further described.

[0098] Specifically, the first modulation unit 201 and the second modulation unit 202 are both configured as metalenses. In this embodiment, the first modulation unit 201 and the second modulation unit 202 can converge the emitted light of the light source 10, such as off-axis focusing, and the light beams are accurately emitted to the same area of ​​the detection module 30 (i.e., the detector 301) after convergence, thereby forming an interference pattern, and making more pixels on the detector 301 that can sense the light intensity of the interference pattern.

[0099] Furthermore, at least one modulation unit (201, 202) in the interference device 20 is configured as a superlens, and the distance between the at least one modulation unit (201, 202) and the detection module 30 (i.e., the detector 301) along the optical axis is not greater than the modulation focal length of the at least one modulation unit (201, 202). In this embodiment, preferably, both modulation units (201, 202) are configured as superlenses, and the distance between the two modulation units (201, 202) and the detection module 30 (i.e., the detector 301) along the optical axis is not greater than (e.g., less than) the modulation focal length corresponding to the two modulation units (201, 202). Therefore, the two modulation units (201, 202) and the detection module 30 (i.e., detector 301) are in a defocused state, so that the focus of the target band light is located on the side of the detection module 30 (i.e., detector 301) away from the photosensitive surface, thereby making the spot area of ​​the target band light on the detector 301 larger, and the detector 301 can sense a larger area, which is conducive to the detector 301 sensing the interference pattern.

[0100] Moreover, compared with the method of focusing on the detection module 30 (i.e., the detector 301), and compared with other defocusing methods, such as the defocusing method of "the distance between the modulation unit (201, 202) and the detection module 30 (i.e., the detector 301) along the optical axis is greater than the modulation focal length corresponding to the modulation unit (201, 202)", the preferred defocusing method in this embodiment can reduce the distance between the modulation unit (201, 202) and the detection module 30 (i.e., the detector 301), thereby reducing the volume of the sensing system.

[0101] Of course, in other embodiments, the distance along the optical axis between the aforementioned at least one modulation unit (201, 202) and the detection module 30 (i.e., the detector 301) may be greater than the modulation focal length of the aforementioned at least one modulation unit (201, 202), in which case at least one of the two modulation units (201, 202) and the detection module 30 (i.e., the detector 301) is also in a defocused state, that is, at least one of the two modulation units (201, 202) is in a defocused state. Alternatively, the distance along the optical axis between the aforementioned at least one modulation unit (201, 202) and the detection module 30 (i.e., the detector 301) is equal to the modulation focal length of the aforementioned at least one modulation unit (201, 202), in which case at least one of the two modulation units (201, 202) and the detection module 30 (i.e., the detector 301) is also in a focused state.

[0102] Since only the interference pattern of the coherent light needs to be obtained on the detector 301, it is not necessary to form a minimum focused light spot on the surface of the detector 301, and it can also be out of focus. Figure 5 The effect shown is that both beams are out of focus.

[0103] In an embodiment not shown, the first modulation unit 201 may be focused on the detection module 30 (i.e., the detector 301), and the second modulation unit 202 may be defocused from the detection module 30 (i.e., the detector 301). Alternatively, both the first modulation unit 201 and the second modulation unit 202 may be focused on the detection module 30 (i.e., the detector 301).

[0104] Specifically, when the light source 10 emits divergent light, the phase distribution of the first modulation unit 201 and the second modulation unit 202 at least satisfies:

[0105]

[0106] Where λ0 is the vacuum wavelength, n is the refractive index of the environment in which the metasurface is located, X and Y are the position coordinates of different positions on the metasurface, and X f and Y f is the intersection coordinate. For example, formula (2) is applicable to the off-axis focusing scenario.

[0107] refer to Figure 6 As shown, a preferred third embodiment of the present invention provides a sensing system, in which the first modulation unit 201 is configured as a super lens and the second modulation unit 202 is configured as a grating, so that the corresponding pixel (for example, a specific pixel) on the detector 301 has a better sensing effect. In this embodiment, the same reference numerals represent the same elements with similar functions and are not further described.

[0108] Specifically, the first modulation unit 201 is configured as a metalens, and the second modulation unit 202 is configured as a grating. In this embodiment, the first modulation unit 201 can converge the emitted light of the light source, and the second modulation unit 202 can deflect the emitted light of the light source, and finally the light beams are accurately emitted to the same area of ​​the detection module 30 (i.e., the detector 301), thereby forming an interference pattern.

[0109] Moreover, when the first modulation unit 201 is configured as a metalens and the second modulation unit 202 is configured as a grating, the interference pattern formed is similar to Newton's rings, and the light intensity at the Newton's rings varies greatly. Therefore, using the corresponding pixels (such as specific pixels) on the detector 30 to sense the light intensity at this location can obtain a better sensing effect (or sensing effect).

[0110] Furthermore, at least one modulation unit (201, 202) in the interference device 20 is configured as a super lens, and the distance between the at least one modulation unit (201, 202) and the detection module 30 (i.e., the detector 301) along the optical axis is not greater than the modulation focal length of the at least one modulation unit (201, 202). In this embodiment, the first modulation unit 201 is configured as a super lens, and the distance between the first modulation unit 201 and the detection module 30 (i.e., the detector 301) along the optical axis is not greater than the modulation focal length corresponding to the first modulation unit 201. Therefore, the first modulation unit 201 and the detection module 30 (i.e., the detector 301) are in a defocused state, so that the focus of the target band light is located on the side of the detection module 30 (i.e., the detector 301) away from the photosensitive surface, so that the spot area of ​​the target band light on the detection module 30 (i.e., the detector 301) is larger, and the detector 301 can sense more area, which is conducive to the detector 301 sensing the interference pattern.

[0111] In an embodiment not shown, the first modulation unit 201 may also be focused on the detection module 30 (i.e., the detector 301). Alternatively, the distance between the first modulation unit 201 and the detection module 30 (i.e., the detector 301) along the optical axis is greater than the modulation focal length corresponding to the first modulation unit 201.

[0112] refer to Figures 7 to 14As shown, some other preferred embodiments of the present invention provide a sensing system, in which the outgoing light of the two modulation units (201, 202) of the interference device 20 is transmitted to the detector 301 by using two optical waveguides (302, 303) to respectively transmit the outgoing light, thereby improving the stability of the sensing system during detection.

[0113] Specific, with reference Figure 7 and Figure 8 As shown, the detection module 30 includes a first optical waveguide 302 and a second optical waveguide 303, wherein the first optical waveguide 302 is configured to transmit the output light of the first modulation unit 201 to the detector 301, and the second optical waveguide 303 is configured to transmit the output light of the second modulation unit 202 to the detector 301. In this embodiment, the two optical waveguides (302, 303) play a role in binding and transmitting light, thereby transmitting the output light of the two modulation units (201, 202) to the detector 301.

[0114] Furthermore, the output lights of the two modulation units (201, 202) already have a phase difference before being coupled into the optical waveguide, and the phase difference is coupled into the detector 301 through the corresponding optical waveguide, thereby achieving the detection requirement of the sensing system. That is, by converting the phase difference between the output lights of the two modulation units (201, 202) into a change in light intensity sensed by the detector 301, the parameter to be measured of the sensing system is obtained.

[0115] Exemplarily, the detection module 30 also includes a first coupling grating 304 and a second coupling grating 305, the first coupling grating 304 is configured to transmit the output light of the first modulation unit 201 to the first optical waveguide 302, and the second coupling grating 305 is configured to transmit the output light of the second modulation unit 202 to the second optical waveguide 303, thereby realizing light transmission between the interference device 20 and the detector 301.

[0116] Furthermore, there is a phase difference between the output lights of the two optical waveguides (302, 303). In this embodiment, the phase difference between the output lights of the two optical waveguides (302, 303) can be generated by only the two modulation units (201, 202), or by the two modulation units (201, 202) and the two optical waveguides (302, 303).

[0117] Specifically, the first optical waveguide 302 and the second optical waveguide 303 are configured as optical waveguides of the same medium (for example, both are configured as conventional waveguides), and the material of the optical waveguide includes but is not limited to silicon, silicon nitride, silicon oxynitride, organic polymer, or a material with low light loss in the working band. At this time, the two optical waveguides (302, 303) only have the function of light transmission, that is, the phase difference detected by the detector 301 is only generated by the interference device 20 (that is, the two modulation units).

[0118] Specifically, the first optical waveguide 302 and / or the second optical waveguide 303 are configured as grating waveguides, photonic crystal waveguides, optical waveguides with free shapes, or supersurface waveguides. At this time, the two optical waveguides (302, 303) can not only have the function of light transmission, but also generate a phase difference, that is, the phase difference detected by the detector 301 is jointly generated by the two modulation units (201, 202) and the two optical waveguides (302, 303).

[0119] The first optical waveguide 302 and the second optical waveguide 303 may be of the same type or different types, as long as a phase difference exists after the light is transmitted through the two optical waveguides (302, 303).

[0120] Exemplarily, the first optical waveguide 302 and the second optical waveguide 303 are optical waveguides of different types, so as to facilitate the generation of phase difference and simplify the design. Fig. 9 a and Fig. 9 As shown in b, the first optical waveguide 302 is configured as a grating waveguide, and the second optical waveguide 303 is configured as a conventional waveguide. Fig.10 a, the first optical waveguide 302 is configured as a photonic crystal waveguide, and the second optical waveguide 303 is configured as a conventional waveguide. Fig.10 b, the first optical waveguide 302 is configured as an optical waveguide having a free shape, and the second optical waveguide 303 is configured as a conventional waveguide. Fig.11 The first optical waveguide 302 is configured as a supersurface waveguide (ie, a nanostructure is arranged on the surface of the optical waveguide, or a nanostructure can also be arranged inside the optical waveguide), and the second optical waveguide 303 is configured as a conventional waveguide.

[0121] In other embodiments, the first optical waveguide 302 and the second optical waveguide 303 may also be optical waveguides of the same type, as long as a phase difference exists after the light is transmitted through the two optical waveguides (302, 303). For example, grating waveguides, photonic crystal waveguides, free-form optical waveguides or metasurface waveguides are used.

[0122] When the sensing system is used for detection, the aforementioned optical waveguides (e.g. Fig. 9 a and Fig. 9 The grating waveguide in b, Fig.10 The photonic crystal waveguide in a, Fig.10 b has a free-form optical waveguide or Fig.11 The metasurface waveguide (302, 303) is exposed to the environment to be measured, and the phase difference between the light emitted by the two optical waveguides (302, 303) is converted into a light intensity change sensed by the detector 301, so as to obtain the parameter to be measured of the sensing system (i.e. the parameter of the environment to be measured).

[0123] Among them, when the aforementioned multiple optical waveguides transmit light in the environment to be tested, evanescent waves will exist. When the parameters of the environment to be tested (such as voltage, temperature, humidity, gas concentration, fluid density) change and cause the refractive index of the environment to be tested to change, a phase difference will be generated between the two optical waveguides (302, 303).

[0124] Therefore, an additional phase difference (i.e., the phase difference generated between the two optical waveguides) is added on the basis of the phase difference generated by the two modulation units (201, 202) (i.e., the interference device 20), which is beneficial to the detection of the sensing system.

[0125] Mate Reference Fig.12 , a sensing structure 306 is disposed on the first optical waveguide 302, and the refractive index of the sensing structure 306 changes with changes in environmental parameters. In this embodiment, the sensing structure 306 is exposed to the environment to be measured. When the environmental parameters to be measured (such as voltage, temperature, humidity, gas concentration, fluid density) change and affect the refractive index of the sensing structure 306, a phase difference will be generated between the two optical waveguides (302, 303), and the phase difference will be converted into a change in light intensity sensed by the detector 301, so that the parameters to be measured of the sensing system (i.e., the parameters of the environment to be measured) can be obtained.

[0126] For example, Fig.12 Both optical waveguides ( 302 , 303 ) are conventional waveguides, and a sensing structure 306 is disposed on the first optical waveguide 302 .

[0127] Mate Reference Fig.13 The first optical waveguide 302 is provided with a refractive index adjustable structure 307 to adjust the phase difference between the output lights of the two optical waveguides (302, 303). In this embodiment, the refractive index adjustable structure 307 is configured as a structure (such as an electrically controlled material) that can change its own refractive index by adjusting a voltage. By providing the refractive index adjustable structure 307, the phase difference between the output lights of the two optical waveguides (302, 303) is changed, so as to calibrate the sensing system.

[0128] Exemplarily, when the phase difference between the output lights of the two optical waveguides (302, 303) is just in the destructive interference state (i.e., the phase difference value is π), the phase difference between the output lights of the two optical waveguides (302, 303) is changed by changing the operating voltage of the refractive index adjustable structure 307, that is, the phase difference between the output lights of the two optical waveguides (302, 303) is not in the destructive interference state, thereby improving the signal-to-noise ratio, which is beneficial to the sensing of the detector 301.

[0129] In some embodiments not shown, the sensing system can generate a phase difference only by two optical waveguides (302, 303), so that the interference device 20 can be omitted, and the parameter to be measured of the sensing system can be obtained by converting the phase difference between the output lights of the two optical waveguides (302, 303) into a change in light intensity sensed by the detector 301.

[0130] Of course, the interference device 20 can also be composed of a first modulation unit 201 and a second modulation unit 202 located in the same spatial position. Alternatively, a conventional optical element or optical system can be used instead of the metasurface-based interference device 20, as long as it can transmit the output light of the light source 10 to the two optical waveguides (302, 303).

[0131] Specifically, the detection module 30 includes a first optical waveguide 302, a second optical waveguide 303 and a detector 301. The output lights of the two optical waveguides (302, 303) have a phase difference. As for the method of making the output lights of the two optical waveguides (302, 303) have a phase difference, please refer to the above, and no further details will be given here.

[0132] Exemplarily, after the output light of the light source 10 is transmitted to the two optical waveguides (302, 303), it is transmitted to the detector 301 via the two optical waveguides (302, 303), and the phase difference between the output lights of the two optical waveguides (302, 303) is converted into a change in light intensity sensed by the detector 301, so that the measured parameters of the sensing system (i.e., the measured environmental parameters) can be obtained.

[0133] When the sensing system is detecting, the aforementioned optical waveguides (such as Fig. 9 a and Fig. 9 The grating waveguide in b, Fig.10 The photonic crystal waveguide in a, Fig.10 b has a free-form optical waveguide, Fig.11 Metasurface waveguides, Fig.12 The sensing structure 306 of the first optical waveguide in the sensor system is exposed to the environment to be measured, and the phase difference between the light emitted by the two optical waveguides (302, 303) is converted into a change in light intensity sensed by the detector 301, so as to obtain the parameter to be measured of the sensing system (i.e. the parameter of the environment to be measured).

[0134] Among them, when the aforementioned multiple optical waveguides transmit light in the environment to be tested, evanescent waves will exist. When the parameters of the environment to be tested (such as voltage, temperature, humidity, gas concentration, fluid density) change and cause the refractive index of the environment to be tested to change, a phase difference will be generated between the two optical waveguides (302, 303).

[0135] For example, Fig.14 ,Will Fig. 9 a and Fig. 9When the grating waveguide in b (ie, the first optical waveguide 302) is exposed to the environment to be tested, after the environmental refractive index changes (ie, environmental parameters, including temperature, humidity, gas concentration, fluid density), the light intensity sensed by the detector 301 also changes accordingly.

[0136] According to another aspect of the present invention, a design method for a sensor system is also provided. The structure and function of the sensor system are as described above and will not be described in detail here.

[0137] Specifically, the design method of the sensor system includes the following steps:

[0138] When the sensor uses only the interference device 20 to detect the measured parameter, step S10, according to the measured parameter of the sensing system, the interference device 20 is correspondingly designed. In this embodiment, the corresponding design of the interference device 20 includes the material selection of the metasurface substrate, the arrangement of the nanostructure, and other structures of the interference device 20 (such as adding a deformation layer), so as to meet the measurement requirements of the sensing system.

[0139] Step S20, using specific pixels (e.g., at least one specific pixel) of the detector 301 to sense the light intensity of different parameters to be measured, and obtaining the change relationship between the parameter to be measured and the light intensity corresponding to the specific pixel. In this embodiment, in the area where the interference pattern is formed on the detection module 30 (i.e., the detector 301), at least one pixel is selected as a specific pixel, and the change relationship between the parameter to be measured and the light intensity is obtained by sensing the specific pixel. When the sensing system is measuring, after obtaining the light intensity value of the specific pixel, the parameter to be measured corresponding to the light intensity value can be determined according to the change relationship between the parameter to be measured and the light intensity.

[0140] Step S30, select any parameter to be measured as a calibration parameter, and use the calibration parameter as a reference value when the sensor system is measuring. In this embodiment, when a pixel is selected as a specific pixel, the same light intensity value may correspond to multiple parameters to be measured. Therefore, before judging the measurement result, the light intensity value obtained by the actual measurement is compared with the light intensity value corresponding to the calibration parameter, thereby narrowing the screening and judgment range of the light intensity value, that is, screening out some light intensity values ​​that are obviously inconsistent. Then, the change relationship between the parameter to be measured and the light intensity is used to judge the parameter to be measured that is actually measured, thereby improving the measurement accuracy of the sensor system.

[0141] Furthermore, in step S10, the first modulation unit 201 and / or the second modulation unit 202 are correspondingly designed according to the parameter to be measured of the sensing system. In this embodiment, it is only necessary to design at least one modulation unit (201, 202) in the interference device 20, and use the modulation unit to measure the parameter to be measured, so as to realize the measurement based on the interference principle. Because when the parameters of the environment in which at least one modulation unit (201, 202) in the interference device 20 is located or other sensing parameters change, the interference pattern will be changed. Therefore, it is not necessary for the entire interference device 20 to measure the parameter to be measured, which simplifies the structure of the interference device 20 and saves costs.

[0142] Specifically, in step S10 , in order to measure the parameter to be measured (such as temperature, humidity, fluid density) using only one modulation unit ( 201 , 202 ), a partition 203 may be provided between the first modulation unit 201 and the second modulation unit 202 .

[0143] Furthermore, in step S20, at least two specific pixels are selected, and the relationship between the measured parameter and the light intensity corresponding to the at least two specific pixels is obtained. In this embodiment, when two or more pixels are selected as specific pixels, the relationship between the measured parameter and the light intensity is obtained more accurately, avoiding the situation where the same light intensity value may correspond to multiple measured parameters, thereby improving the measurement accuracy of the sensing system.

[0144] Exemplarily, when the area of ​​the interference spot formed on the detector 301 is larger than the area of ​​two pixels, at least two specific pixels are set to ensure that the corresponding light intensity change can be detected.

[0145] Specifically, in step S10, in order to realize that each modulation unit (201, 202) of the interference device 20 emits the light from the light source 10 to the same area of ​​the detection module 30 (i.e., the detector 301) after modulating the light emitted by the light source 10, the first modulation unit 201 and the second modulation unit 202 may be configured as a grating or a super lens; or, the first modulation unit 201 may be configured as a super lens, and the second modulation unit 202 may be configured as a grating.

[0146] Specifically, when the modulation units (201, 202) are configured as gratings, formula (1) can be used to arrange the nanostructures. When the modulation units (201, 202) are configured as metalenses, formula (2) can be used to arrange the nanostructures.

[0147] Specifically, in step S10, the parameter to be measured is configured as the refractive index of the environment in which the interference device 20 is located. Figure 1In the illustrated solution, the environment where the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) is located may be the light incident side and / or the light emitting side of the interference device 20. Figure 2 In the illustrated solution, the environment where the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) is located can be the light incident side of the interference device 20. By changing the temperature, humidity, and fluid density (e.g., air density, liquid density) of the environment where the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) is located, the refractive index of the environment where the interference device 20 is located can be changed, thereby inferring the corresponding change in temperature, humidity, or fluid density based on the change in the refractive index.

[0148] Specifically, in step S10, the parameter to be measured is configured as the pressure exerted on the interference device 20. In this embodiment, the substrate of the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) is made of an elastic material, for example, a material with a large elastic modulus and yield strength, and the substrate of the elastic material can be used to measure pressure, that is, a certain pressure is applied to the substrate of the interference device 20, and the elastic deformation of the substrate will cause the divergence of the exit angle of the reflected parallel light, and the pressure information and the pressure change can be obtained by detecting the change of the interference pattern.

[0149] Specifically, in step S10, the parameter to be measured is configured as the temperature of the environment in which the interference device 20 is located. In this embodiment, by wrapping the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) in a deformation layer, the deformation layer uses a material with a large thermal expansion coefficient, and the temperature change will cause the expansion change at the exit interface, thereby causing the phase difference between the exit lights of the two modulation units (201, 202) to change, that is, causing the phase changes of the two interference lights on the detector 301 to different degrees, and the temperature value and the temperature change can be obtained by detecting the change of the interference pattern.

[0150] Further, in step S10, when the parameter to be measured is configured as the refractive index of the environment in which the interference device 20 is located, the change in the density of the fluid in the environment in which the interference device 20 is located, the change in the humidity of the environment in which the interference device 20 is located, or the change in the temperature of the environment in which the interference device 20 is located is determined based on the change in the refractive index of the environment in which the interference device 20 is located. In this embodiment, when it is necessary to determine the change in the density of the fluid in the environment in which the interference device 20 is located, it is only necessary to control other variables that affect the refractive index of the environment (such as temperature, humidity, etc.) unchanged. The change in the refractive index of the environment is achieved by changing the density of the fluid alone, so that the density of the fluid in the environment is determined accordingly according to the change relationship between the parameter to be measured (i.e., the refractive index of the environment) and the light intensity.

[0151] Similarly, changes in humidity of the environment in which the interference device 20 is located or changes in temperature of the environment in which the interference device 20 is located can also be measured in the above manner.

[0152] Specifically, Figure 3 Taking the sensor system shown in the figure as an example, the design method of the sensor system is specifically described. Fig.15 As shown, after being deflected by the first modulation unit 201 and the second modulation unit 202, the emitted light of the light source 10 is emitted to the same area of ​​the detection module 30 (i.e., the detector 301), and an interference pattern (such as Fig.15 a). When the environmental parameters (e.g., temperature, humidity, fluid density) of the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202) change, the interference pattern (i.e., light spot) formed by the interference device 20 on the detection module 30 (i.e., the detector 301) will also change, such as Fig.16 As shown, the interference pattern is displaced. The light intensity value sensed by a specific pixel on the detector 301 changes with the change of the interference pattern in the detection module 30 (i.e., the detector 301), and the actual measured parameter can be obtained by using the change relationship between the parameter to be measured and the light intensity in step S20.

[0153] like Fig.17 As shown, when the incident light of the target wavelength band (for example, a wavelength of 1550nm) is vertically incident on the first modulation unit 201 and the second modulation unit 202, the refractive index of the environment in which the interference device 20 is located is 1, and the initial deflection angles of the first modulation unit 201 and the second modulation unit 202 are 12.5° and 2.5°. When the refractive index of the environment in which the interference device 20 is located increases, according to the phase formula (1), an additional phase factor related to the refractive index is introduced into the metasurface structure, and an additional angle deflection effect can be obtained compared with the traditional mirror that conforms to the law of reflection. When the refractive index of the environment in which the interference device 20 is located changes from 1 to 1.1, the exit angles of the first modulation unit 201 and the second modulation unit 202 become 11.3° and 2.3°, respectively. Fig.18 Taking the coherent irradiance of the pixel at (x=0, y=0) (shown by the solid line in the figure) and the pixel at (x=0, y=20um) (shown by the dotted line in the figure) on the detector 301 as an example, the change curve of the light intensity sensed by the two specific pixels in the process of gradually increasing the refractive index (i.e., the change relationship between the parameter to be measured and the light intensity in step S20) is obtained. According to the change amount and change trend of the two pixels, the current environmental refractive index (i.e., the parameter to be measured actually measured) or the refractive index change trend can be obtained.

[0154] In addition, if a specific gas is introduced to cause the refractive index of the environment in which the interference device 20 is located to change, the corresponding gas concentration can be obtained. The refractive index of the environment in which the first modulation unit 201 and the second modulation unit 202 are located can change synchronously or only one of them can change, and both can produce changes in the interference pattern. The purpose of changing only one of the refractive indexes of the environment can be achieved by adding a partition 203 that is transparent to the target wavelength band light between the first modulation unit 201 and the second modulation unit 202.

[0155] Specifically, information of more pixels (ie, specific pixels) can be collected to obtain a more accurate refractive index distribution. Moreover, it is preferred to use a detector 301 with a higher sampling frequency, for example, the sampling speed is greater than the inverse of the time required for the refractive index to change by 0.01.

[0156] When the parameter to be measured in step S10 is configured as the pressure exerted on the interference device 20, a substrate material with a large elastic modulus and yield strength is selected, and a certain pressure is applied to the surface of the interference device 20 (i.e., the first modulation unit 201 and / or the second modulation unit 202). The elastic deformation of the substrate will cause the divergence of the exit angle of the reflected parallel light, and the pressure information and pressure changes can be obtained by detecting the changes in the interference pattern.

[0157] Mate Reference Fig.19 and Fig. 20 As shown, when the interference device 20 is subjected to pressure, taking the coherent irradiance of the pixel at (x=0, y=0) (shown by the solid line in the figure) and the pixel at (x=0, y=20um) (shown by the dotted line in the figure) on the detector 301 as examples, the change of the light intensity at two specific pixels with the pressure is obtained. Fig.19 The first modulation unit 201 and the second modulation unit 202 are both subjected to the same pressure. Fig. 20 The first modulation unit 201 is subjected to pressure. By sensing the change in the intensity of the interference fringes on a specific pixel, the corresponding pressure value can be obtained.

[0158] It should be noted that the yield strength of most metal materials and dielectric materials is relatively small, and the pressure value that can be sensed is also relatively small, so it is preferred to use a detector with a high dynamic range that can detect tiny changes in light intensity.

[0159] Specifically, Figure 5 Taking the sensor system shown in the figure as an example, the design method of the sensor system is specifically described. Fig.21 As shown, after the outgoing light of the light source 10 is converged (e.g., off-axis focusing) by the first modulation unit 201 and the second modulation unit 202, it is emitted to the same area of ​​the detection module 30 (i.e., the detector 301), and an interference pattern (e.g., Fig.21a). It can be seen that the light intensity at each pixel can be used as a reference for the change in light intensity during the interference image change process to determine the corresponding parameter to be measured.

[0160] When the environmental parameters (such as temperature, humidity, and fluid density) of the interference device 20 change, the interference pattern (i.e., light spot) formed by the interference device 20 on the detection module 30 (i.e., the detector 301) will also change. The light intensity value sensed by a specific pixel on the detector 30 changes with the change of the interference pattern on the detection module 30 (i.e., the detector 301). The actual measured parameter can be obtained by using the change relationship between the parameter to be measured and the light intensity in step S20. Fig. 22 In order to change only the refractive index of the environment where the first modulation unit 201 is located, Fig.23 In order to change the refractive index of the environment in which the first modulation unit 201 and the second modulation unit 202 are located at the same time, it can be seen that both interference images have changed compared with those before the measurement.

[0161] Specifically, Figure 6 Taking the sensor system shown in the figure as an example, the design method of the sensor system is specifically described. Fig.24 As shown, after the outgoing light of the light source 10 is converged by the first modulation unit 201 (e.g., off-axis focusing) and deflected by the second modulation unit 202, it is emitted to the same area of ​​the detection module 30 (i.e., the detector 301), and an interference pattern (e.g., Fig.24 a). Fig.24 b. From the intercept at y=0, it can be seen that a better sensing effect can be obtained at a specific pixel position (i.e., at the Newton ring). Therefore, when the pixel at (x=0, y=20um) is used as a specific pixel, the sensed light intensity changes more and the measurement result is more accurate.

[0162] When the environmental parameters (such as temperature, humidity, and fluid density) of the interference device 20 change, the interference pattern (i.e., light spot) formed by the interference device 20 on the detection module 30 (i.e., the detector 301) will also change. The light intensity value sensed by a specific pixel on the detector 301 changes with the change of the interference pattern on the detection module 30 (i.e., the detector 301). The actual measured parameter can be obtained by using the change relationship between the parameter to be measured and the light intensity in step S20. Fig.25 In order to change only the refractive index of the environment where the first modulation unit 201 is located, Fig.26 In order to change the refractive index of the environment in which the first modulation unit 201 and the second modulation unit 202 are located at the same time, it can be seen that both interference images have changed compared with those before the measurement.

[0163] When the sensor uses the interference device 20 and the optical waveguide (such as the first optical waveguide 302) to detect the parameter to be measured, in step S10, the interference device 20 and the detection module 30 are correspondingly designed according to the parameter to be measured of the sensing system.

[0164] When the sensor uses only an optical waveguide (such as the first optical waveguide 302 ) to detect the parameter to be measured, in step S10 , the detection module 30 is designed accordingly according to the parameter to be measured of the sensing system.

[0165] In step S10, according to the parameter to be measured of the sensing system, the first optical waveguide 302 and / or the second optical waveguide 303 are correspondingly designed. In this embodiment, by configuring the first optical waveguide 302 and / or the second optical waveguide 303 as a grating waveguide, a photonic crystal waveguide, an optical waveguide with a free shape or a metasurface waveguide, and / or providing a sensing structure 306 on the first optical waveguide 302, a phase difference is achieved between the output lights of the two optical waveguides (302, 303).

[0166] In step S10, the first optical waveguide 302 is provided with a refractive index adjustable structure 307 to adjust the phase difference between the output lights of the two optical waveguides (302, 303), thereby calibrating the sensing system.

[0167] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0168] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sensing system, characterized in that: It includes a light source, an interference device and a detection module arranged along the transmission direction of the light path. The interference device is configured as a metasurface and includes a first modulation unit and a second modulation unit. The detection module includes a detector for sensing the light signal. After the interference device modulates the output light of the light source, there is a phase difference between the output lights of the two modulation units and both are transmitted to the detector.

2. The sensor system according to claim 1, characterized in that The light source and the detection module are located on the same side of the interference device; Alternatively, the light source and the detection module are located on opposite sides of the interference device.

3. The sensor system according to claim 1, characterized in that The metasurface includes a substrate, and the first modulation unit and the second modulation unit use the same substrate; Alternatively, the first modulation unit and the second modulation unit respectively use separate substrates.

4. The sensor system according to claim 1, characterized in that The interference device and the light source are arranged along the optical axis, and / or the interference device and the detection module are arranged along the optical axis.

5. The sensor system according to claim 1, characterized in that: The light emitted by the light source is coherent light.

6. The sensor system according to claim 1, characterized in that: The first modulation unit and the second modulation unit are both configured as gratings or super lenses; Alternatively, the first modulation unit is configured as a superlens, and the second modulation unit is configured as a grating.

7. The sensor system according to claim 1, characterized in that: At least one modulation unit in the interference device is configured as a superlens, and the distance between the at least one modulation unit and the detection module along the optical axis is not greater than the modulation focal length of the at least one modulation unit.

8. The sensor system according to claim 1, characterized in that: The interference device further includes a partition located between the first modulation unit and the second modulation unit, and the partition is configured to transmit the target wavelength band light of the interference device.

9. The sensor system according to claim 1, characterized in that: The metasurface includes a substrate, and the substrate of the first modulation unit and / or the second modulation unit is made of elastic material.

10. The sensor system according to claim 1, characterized in that: The interference device further includes a deformation layer wrapped around the first modulation unit and / or the second modulation unit, and the deformation layer is made of a thermal expansion material.

11. The sensor system according to claim 1, characterized in that: The detection module includes a first optical waveguide and a second optical waveguide, wherein the first optical waveguide is configured to transmit the output light of the first modulation unit to the detector, and the second optical waveguide is configured to transmit the output light of the second modulation unit to the detector, and there is a phase difference between the output lights of the two optical waveguides.

12. The sensor system according to claim 11, characterized in that The first optical waveguide and / or the second optical waveguide is configured as a grating waveguide, a photonic crystal waveguide, an optical waveguide having a free shape, or a supersurface waveguide.

13. The sensor system according to claim 11, characterized in that A sensing structure is arranged on the first optical waveguide, and the refractive index of the sensing structure changes with the change of environmental parameters.

14. The sensor system according to claim 11, characterized in that The first optical waveguide is provided with a refractive index adjustable structure to adjust the phase difference between the output lights of the two optical waveguides.

15. A method for designing a sensor system according to any one of claims 1 to 14, characterized in that: include: According to the parameters to be measured of the sensing system, design interference devices and / or detection modules accordingly; Utilize specific pixels of the detector to sense the light intensity of different parameters to be measured, and obtain the change relationship between the parameter to be measured and the light intensity corresponding to the specific pixels; Select any parameter to be measured as a calibration parameter, and use the calibration parameter as a reference value when measuring the sensor system.

16. The method for designing a sensor system according to claim 15, characterized in that: According to the parameters to be measured of the sensing system, the first modulation unit and / or the second modulation unit are designed accordingly.

17. The method for designing a sensor system according to claim 15, characterized in that: At least two specific pixels are selected, and a variation relationship between the parameters to be measured and the light intensity corresponding to the at least two specific pixels is obtained.

18. The method for designing a sensor system according to claim 15, characterized in that: The parameter to be measured is configured to be the refractive index of the environment in which the interference device is located, the pressure on the interference device, or the temperature of the environment in which the interference device is located.

19. The method for designing a sensor system according to claim 18, characterized in that: When the parameter to be measured is configured as the refractive index of the environment in which the interference device is located, the change in the fluid density of the environment in which the interference device is located, the change in the humidity of the environment in which the interference device is located, or the change in the temperature of the environment in which the interference device is located is determined based on the change in the refractive index of the environment in which the interference device is located.

20. The method for designing a sensor system according to claim 15, characterized in that: The detection module includes a first optical waveguide and a second optical waveguide. The first optical waveguide and / or the second optical waveguide are designed accordingly according to the parameters to be measured of the sensing system.

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