Image sensor and imaging apparatus

Abstract

The utility model provides a kind of image sensor and imaging equipment, image sensor includes photoelectric chip and super surface, the super surface is located photoelectric chip's light entrance side, the super surface is configured as Bragg grating, to transmit the incident light of working waveband to photoelectric chip, and the incident light of non-working waveband is reflected, the image sensor further includes adjusting device, the adjusting device is used to adjust the working waveband of super surface;Super surface is configured as Bragg grating, can narrow line width, so that Bragg grating is applied to image sensor, can reduce the volume of whole and reduce manufacturing cost.

Description

Technical Field

[0001] This utility model relates to the field of imaging technology, and in particular to an image sensor and imaging device. Background Technology

[0002] Existing image sensors typically use gratings to narrow the linewidth, such as Bragg gratings, to achieve sensing of specific wavelengths. However, the large size and complex materials of Bragg gratings lead to an increase in overall size and manufacturing cost when used in image sensors. Summary of the Invention

[0003] The purpose of this invention is to provide an image sensor and imaging device that can reduce the overall size and manufacturing cost.

[0004] To achieve one of the above-mentioned objectives, one embodiment of this utility model provides an image sensor, comprising:

[0005] Optoelectronic chips;

[0006] A metasurface is located on the light-incident side of the optoelectronic chip. The metasurface is configured as a Bragg grating to transmit incident light in the working band to the optoelectronic chip and reflect incident light in the non-working band.

[0007] The image sensor also includes an adjustment device for adjusting the operating wavelength of the metasurface.

[0008] As a further improvement of one embodiment of the present invention, the metasurface includes an array of nanostructures, the nanostructures being made of phase change materials, and the regulating device being used to regulate the temperature at the nanostructures.

[0009] As a further improvement of one embodiment of the present invention, the metasurface further includes a substrate, the adjustment device includes an electrothermal layer located between the substrate and the nanostructure, and the voltage applied to the electrothermal layer by the adjustment device is adjustable.

[0010] As a further improvement of one embodiment of the present invention, the metasurface includes a nanostructure, the adjustment device includes a liquid crystal layer filled between the nanostructures, the thickness of the liquid crystal layer along the optical axis is greater than the height of the nanostructure along the optical axis, and the adjustment device is used to adjust the equivalent refractive index or polarization response at the nanostructure.

[0011] As a further improvement of one embodiment of the present invention, the metasurface includes a substrate, and the adjustment device further includes a first electrode layer and a second electrode layer located on both sides of the liquid crystal layer. The first electrode layer is located between the substrate and the nanostructure, and the voltage applied to the first electrode layer and the second electrode layer by the adjustment device is adjustable.

[0012] As a further improvement of one embodiment of the present invention, the metasurface includes a nanostructure, and the adjustment device is used to adjust the structural parameters of the nanostructure. The structural parameters include at least one of the following parameters: the period of the superstructure unit in which the nanostructure is located, the characteristic size of the nanostructure, and the arrangement of the nanostructure.

[0013] As a further improvement of one embodiment of the present invention, the metasurface includes a substrate made of an elastic material, and the force applied to the substrate by the adjustment device is adjustable to drive the substrate to produce elastic deformation.

[0014] As a further improvement of one embodiment of the present invention, the adjustment device is used to adjust the incident angle of the incident light onto the metasurface.

[0015] As a further improvement of one embodiment of the present invention, the image sensor includes an antireflection film disposed on the light-incident side and the light-outcident side of the metasurface, the antireflection film including alternating silicon nitride layers and silicon oxide layers, and the antireflection film is integrally formed with the optoelectronic chip.

[0016] As a further improvement of one embodiment of the present invention, the image sensor includes multiple metasurfaces, which are cascaded on the light-incident side of the optoelectronic chip.

[0017] As a further improvement of one embodiment of the present invention, the metasurface includes a nanostructure, the nanostructure having an asymmetric shape with respect to a first axis and a symmetric shape with respect to a second axis perpendicular to the first axis, both the first axis and the second axis being perpendicular to the optical axis of the metasurface.

[0018] To achieve one of the objectives of the above-mentioned utility model, the present utility model also provides an imaging device, which includes an optical system 200 and an image sensor as described above. The image sensor is located on the image plane of the optical system, and the optical system and the image sensor are either separately configured or integrally formed.

[0019] Compared with the prior art, in the embodiments of this utility model, the metasurface is configured as a Bragg grating, which can narrow the linewidth, so that when the Bragg grating is used in an image sensor, the overall volume can be reduced and the manufacturing cost can be lowered. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the optical path of an image sensor according to one embodiment of the present invention;

[0021] Figure 2 Yes, yes Figure 1 A schematic diagram showing the arrangement of multiple implementations of the superstructure units of the supersurface;

[0022] Figure 3 yes Figure 1 The test spectrum;

[0023] Figure 4 yes Figure 1 Wavelength-reflectivity relationship diagram of the surface of the Chinese Super League after antireflection coating is applied;

[0024] Figure 5 This is a schematic diagram of the adjusting device in one embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the adjusting device in another embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the optical path of the image sensor in another embodiment of the present invention;

[0027] Figure 8 yes Figure 7 The test spectrum;

[0028] Figure 9 This is a schematic diagram of the optical path of an imaging device according to one embodiment of the present invention. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present invention.

[0030] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0031] In the various illustrations of this utility model, for ease of illustration, some dimensions of the structure or part may be exaggerated relative to other structures or parts. Therefore, they are only used to illustrate the basic structure of the subject matter of this utility model.

[0032] Reference Figure 1 As shown, an image sensor includes an optoelectronic chip 30 and a metasurface 10.

[0033] In this embodiment, the optoelectronic chip 30 can be a back-illuminated CMOS (Complementary Metal Oxide Semiconductor).

[0034] In this embodiment, the metasurface 10 refers to an artificial layered material with a size smaller than or approximately equal to the wavelength, which can be regarded as a two-dimensional counterpart of a metamaterial. The metasurface 10 can achieve the control of the polarization, phase, amplitude, frequency, propagation mode, and other characteristics of electromagnetic waves through the surface subwavelength superstructure units 11, thereby realizing characteristics such as beam shaping, beam deflection, superlensing, super holography, optical rotation, anti-reflection and anti-reflection.

[0035] In some embodiments, the metasurface 10 is located on the light-incident side of the photoelectric chip 30. In this embodiment, the metasurface 10 is used to modulate the incident light (e.g., the emitted light from a light source) so that the light is transmitted to the photoelectric chip 30. The photoelectric chip 30 is capable of converting the received optical signal into an electrical signal.

[0036] In some embodiments, the metasurface 10 is configured as a Bragg grating to transmit incident light in the working band to the optoelectronic chip 30 and reflect incident light in the non-working band.

[0037] In this embodiment, the Bragg grating utilizes the Bragg diffraction principle to achieve spectral screening by matching specific wavelengths (i.e., the working band). That is, the periodic structure selectively reflects or transmits light that meets the Bragg condition (wavelength and period matching).

[0038] In this embodiment, the metasurface 10 can adjust the local equivalent refractive index by changing the characteristic size (e.g., size and shape of the nanostructure 12) and arrangement of the nanostructure 12, so that it can produce a transmission phase abrupt change for a specific wavelength (i.e., the working band), forming a periodic structure similar to a chirped Bragg grating.

[0039] In this embodiment, after transmitting incident light of the working band to the optoelectronic chip 30 and reflecting incident light of the non-working band, the metasurface 10 can achieve wavelength stabilization and linewidth narrowing, and can be used in narrowband filtering and wavelength locking scenarios.

[0040] For example, metasurface 10 is configured as a fiber Bragg grating (FBG), such as a chirped fiber Bragg grating (CFBG).

[0041] In this embodiment, the metasurface is configured as a Bragg grating, which can narrow the linewidth, so that when the Bragg grating is used in the image sensor 100, the overall size can be reduced and the manufacturing cost can be lowered.

[0042] In some embodiments, in conjunction with reference Figure 2 As shown, the metasurface 10 has a plurality of periodically arranged superstructure units 11, each of which has a nanostructure 12.

[0043] In this embodiment, the superstructure unit 11 is obtained by dividing the metasurface 10 to obtain structural units centered on each nanostructure 12. The metasurface 10 also includes a substrate 13 connecting the nanostructures 12, and multiple nanostructures 12 are arranged on the substrate 13, wherein the nanostructures 12 in each period form a superstructure unit 11. The superstructure unit 11 is a close-packed pattern, for example, it can be a regular quadrilateral (e.g., ...). Figure 2 a, Figure 2 b、 Figure 2 c) Regular hexagon (such as...) Figure 2 d) Fan-shaped, etc., each cycle contains a nanostructure 12, and the vertices and / or centers of the superstructure unit 11 may be provided with nanostructures 12. For example... Figure 2 d. When the superstructure unit 11 is a regular hexagon, at least one nanostructure 12 is set at the center of the regular hexagon. The same applies to the sector and square cases.

[0044] For example, the light incident (e.g., perpendicularly incident) onto the metasurface 10 is broadband light (e.g., wavelengths can be between 300 nm and 2500 nm, with any bandwidth of at least 50 nm). The incident light can be incident onto the metasurface 10 from one side of the nanostructure 12 or from one side of the substrate 13. The operating wavelength can be 940 ± 3 nm, and the non-operating wavelength refers to any wavelength other than the operating wavelength. The nanostructure 12 is a subwavelength structure, periodically arranged on the substrate 13. After the nanostructures 12 are periodically stacked, they can transmit incident light in the operating wavelength and reflect light in the non-operating wavelength, thereby achieving the function of narrowing the linewidth.

[0045] In some embodiments, the nanostructure 12 is asymmetrical with respect to the first axis. In this embodiment, the projection of the nanostructure 12 onto the XY plane (i.e., the plane perpendicular to the optical axis Z) is asymmetrical with respect to the first axis (e.g., the X-axis), such that the metasurface 10 has a polarization response to incident light polarized along the direction of the first axis (e.g., the X-axis).

[0046] In some embodiments, the nanostructure 12 is symmetrical with respect to a second axis perpendicular to the first axis. In this embodiment, the projection of the nanostructure 12 onto the XY plane (i.e., the plane perpendicular to the optical axis Z) is symmetrical with respect to the second axis (e.g., the Y-axis), and the metasurface 10 has no polarization response to incident light polarized along the direction of the second axis (e.g., the Y-axis).

[0047] In some embodiments, both the first axis and the second axis are perpendicular to the optical axis of the metasurface 10. In this embodiment, the first axis is parallel to the X-axis, and the second axis is parallel to the Y-axis.

[0048] In some embodiments, continue to refer to Figure 2 As shown, the nanostructure 12 includes a first nanopillar 121 and a second nanopillar 122, wherein the first nanopillar 121 and the second nanopillar 122 have the same cross-sectional shape and / or cross-sectional area.

[0049] In this embodiment, the first nanopillar 121 and the second nanopillar 122 are formed on the substrate 13 by a semiconductor etching process.

[0050] In this embodiment, the cross-sectional shape of the first nanopillar 121 is configured as a triangle, a circle, a square, a rectangle, or an ellipse, and the cross-sectional shape of the second nanopillar 122 is configured as a triangle, a circle, a square, a rectangle, or an ellipse.

[0051] In this embodiment, when designing the metasurface 10, we first considered the influence of the cross-sectional shape and periodic arrangement of the nanopillars on the narrowband efficiency and resonant position. Ultimately, we determined that the cross-sectional shape could be triangular, circular, square, rectangular, or elliptical, and the periodic arrangement could be a square or hexagonal lattice. Under these conditions, after passing through the metasurface 10, a Lorentz-shaped transmission peak with a peak value (>99.9%) can be formed, and the side lobes are suppressed to a reflectivity of less than 1%, meaning that only incident light in the working wavelength band is transmitted, while incident light in the non-working wavelength band is reflected. By adjusting the cross-sectional diameter, height, and period size of the superstructure unit 11 of the nanopillars, the center wavelength (i.e., the working wavelength band) and linewidth can be changed to adapt to different requirements.

[0052] In this embodiment, the size of the nanopillar is approximately equal to or slightly smaller than the applicable operating wavelength of the metasurface 10. The circular cross-sectional radius CD can be between 10 nm and 2000 nm, and the height of the nanopillar can be between 10 nm and 2000 nm. For nanopillars with rectangular or elliptical cross-sections, their major or minor axis can be any value of CD mentioned above, and the length of the other axis can be slightly less than or slightly greater than this value.

[0053] In this embodiment, the nanopillars are arranged periodically on the substrate 13 based on regular quadrilaterals, and the size of the period differs in the X-axis and Y-axis directions. In the X-axis direction, the period needs to be slightly smaller than the CD of the nanopillars, which can be 10% to 100% of CD, i.e., between 10 nm and 1000 nm; while in the Y-axis direction, the period needs to be slightly larger than the CD of the nanopillars, which can be about 100% to about 500% of CD, i.e., between 20 nm and 3000 nm.

[0054] For example, such as Figure 2 b. The first nanopillar 121 and the second nanopillar 122 have different cross-sectional shapes. The cross-sectional area of ​​the first nanopillar 121 is not equal to (for example, greater than) the cross-sectional area of ​​the second nanopillar 122. The first nanopillar 121 and the second nanopillar 122 are spaced apart. The first nanopillar 121 and the second nanopillar 122 are spaced apart along the Y-axis. The cross-sectional shape of the first nanopillar 121 and the second nanopillar 122 can be triangular, circular, square, rectangular, or elliptical. Figure 2 b. The cross-sectional shape of the first nanopillar 121 is rectangular, and the cross-sectional shape of the second nanopillar 122 is circular.

[0055] For example, such as Figure 2 c. The first nanopillar 121 and the second nanopillar 122 have the same cross-sectional shape, but the cross-sectional area of ​​the first nanopillar 121 is not equal to (e.g., less than) the cross-sectional area of ​​the second nanopillar 122. The first nanopillar 121 and the second nanopillar 122 are interconnected. The first nanopillar 121 and the second nanopillar 122 are arranged along the Y-axis and interconnected. The cross-sectional shape of the first nanopillar 121 and the second nanopillar 122 can be triangular, circular, square, rectangular, or elliptical. Figure 2 c. The cross-sectional shape of the first nanopillar 121 and the cross-sectional shape of the second nanopillar 122 are both triangular.

[0056] like Figure 2 a and Figure 2 As shown in Figure d, the first nanopillar 121 and the second nanopillar 122 have the same cross-sectional shape and cross-sectional area. Any axis of symmetry of the first nanopillar 121 forms an angle with the first axis, and any axis of symmetry of the second nanopillar 122 forms an angle with the first axis. The cross-sectional shape of the first nanopillar 121 and the second nanopillar 122 can be rectangular or elliptical.

[0057] Furthermore, as the angle between the axis of symmetry of the first nanopillar 121 (or the second nanopillar 122) and the Y-axis gradually increases, the wavelength range reflected by the metasurface 10 becomes larger, resulting in increased bandwidth. Figure 2 After testing the metasurface 10 composed of nanostructure 12 in a, the following results were obtained: Figure 3 The spectrum obtained by projection from metasurface 10 shows a filtering peak with an approximate Lorentz line shape in the selected band. When the transmittance (T) on the vertical axis is 0.5, the corresponding wavelength range on the horizontal axis is 0.088 nm, thus achieving a reflectance greater than 99.9%, an adjustable bandwidth less than 0.1 nm, and sidelobe suppression within 1%.

[0058] In some embodiments not shown, the nanostructure 12 includes a first nanopore and a second nanopore, wherein the first nanopore and the second nanopore have the same pore shape and / or pore area. In this embodiment, the first nanopore and the second nanopore are formed on the substrate 13 by a semiconductor etching process. The first nanopore can be replaced by the aforementioned first nanopillar, and the second nanopore can be replaced by the aforementioned second nanopillar, mainly satisfying that the nanostructure 12 has an asymmetrical shape with respect to the first axis (X-axis) and a symmetrical shape with respect to the second axis (Y-axis).

[0059] In some embodiments, the refractive index of the substrate 13 is lower than that of the nanostructure 12. In this embodiment, the substrate 13 material can be any material with a low refractive index and absorption coefficient in the visible or near-infrared band, such as silicon dioxide (SiO2), spin-coated glass (SOG), or polymers such as polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), and polymethylpentene (PMP), as well as combinations of the above materials. The nanostructure 12, composed of the first nanopillar 121 and the second nanopillar 122, can be a dielectric material with a refractive index higher than that of the substrate 13, such as monomeric silicon (c-Si), polycrystalline silicon (p-Si), amorphous silicon (a-Si), compound semiconductors (such as GaN, GaP, GaAs, SiC, etc.), TiO2, Si3N4, AlSb, AlAs, AlGaAs, AlGaInP, BP, ZnGeP2, and other suitable materials, as well as combinations of the above materials.

[0060] In some embodiments, the metasurface 10 further includes a protective layer 14 covering the nanostructure 12. The material of the protective layer 14 is similar to that of the substrate 13 and can be any material with a low refractive index and absorption coefficient in the visible or near-infrared band, such as silica (SiO2), spin-coated glass (SOG), or polymers such as polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polymethylpentene (PMP), and combinations thereof. The protective layer 14 can also be air, i.e., no protective layer 14 is provided.

[0061] In some embodiments, the image sensor 100 includes an antireflection film 20 disposed on the light-incident side and the light-outcident side of the metasurface 10, the antireflection film 20 including an alternately disposed silicon nitride layer 21 and a silicon oxide layer 22.

[0062] In this embodiment, an antireflection membrane 20 is provided on both the substrate 11 and the filler 14. For example... Figure 1 The antireflection coating 20 has a silicon nitride (Si3N4) layer 21 disposed on the substrate 11 and the filler 14, respectively, and a silicon oxide (SiO2) layer 22 disposed on the silicon nitride layer 21. By providing the antireflection coating 20, the reflectivity in the working wavelength band can be reduced, thereby improving the transmittance in the working wavelength band of the metasurface 10.

[0063] For example, such as Figure 4 The thickness of silicon nitride layer 21 is 202 nm, the thickness of silicon oxide layer 22 is 124 nm, and the reflectivity of the metasurface 10 near the center wavelength (i.e., the working band) of 940 nm is low.

[0064] In some embodiments, the antireflective film 20 is integrally formed with the photoelectric chip 30.

[0065] In this embodiment, the metasurface 10 and the photoelectric chip 30 are interconnected by an antireflection film 20, that is, the metasurface 10 and the photoelectric chip 30 are integrated, so that the metasurface 10 and the photoelectric chip 30 are integrally formed, which can eliminate the assembly process between them.

[0066] For example, the metasurface 10 based on silicon-based or silicon nitride materials can be fabricated at the wafer level using techniques such as electron beam lithography and nanoimprint lithography, and can be seamlessly integrated with the back-end processes of the optoelectronic chip 30. Moreover, the metasurface 10 is a subwavelength-sized optical element (e.g., with a thickness of only a few hundred nanometers to micrometers), which is suitable for the current micrometer-scale optoelectronic chip 30. At the same time, its fabrication process is compatible with mature semiconductor sensor technology, enabling on-chip integration of the image sensor 100 and the driving circuit, significantly reducing packaging complexity, and possessing strong practicality and economy.

[0067] For example, the metasurface 10 designed with Si3N4 or SiO2 composite waveguides can achieve narrowband filtering performance with transmittance >90% and linewidth <0.1nm in the C-band (1530-1565nm), while also being resistant to high-power laser irradiation (>1kW / cm2).

[0068] In some embodiments, in conjunction with reference Figure 5 and Figure 6 As shown, the image sensor 100 also includes an adjustment device (40, 40') for adjusting the operating wavelength of the metasurface 10.

[0069] In this embodiment, compared with the scheme of "using a fixed working band for the Bragg grating", this scheme can achieve multi-band switching by using the adjustment device (40, 40'), increasing the flexibility of the image sensor 100.

[0070] In this embodiment, compared with the scheme of "dynamic tuning by adding a conventional Bragg grating adjustment device", this scheme adopts a metasurface Bragg grating, which can not only reduce the size of the image sensor 100, but also reduce the volume and power of the adjustment device (40, 40'), which is beneficial to adjust the working band of the metasurface 10, thereby increasing the flexibility of the image sensor 100.

[0071] In some embodiments, the nanostructure 12 is made of a phase change material. In this embodiment, the phase change material may be Ge2Sb2Te5, or other materials whose refractive index changes upon temperature.

[0072] In some embodiments, the regulating device 40 is used to regulate the temperature at the nanostructure 12.

[0073] In this embodiment, by introducing a thermo-optical tuning mechanism, such as an integrated microheater, the center wavelength (i.e., the working band) of the metasurface 10 can be dynamically controlled to meet the adaptive wave-locking requirements of multimode lasers. Multi-band filtering switching can be achieved on the same optoelectronic chip 30, breaking through the static characteristic limitations of traditional Bragg gratings.

[0074] In this embodiment, as Figure 5 The adjustment device 40 heats the environment in which the nanostructure 12 is located, thereby changing the refractive index of the phase change material (i.e., the nanostructure 12) and adjusting the working wavelength of the metasurface 10.

[0075] In some embodiments, the regulating device 40 includes an electrothermal layer 41 located between the substrate 13 and the nanostructure 12, and the voltage applied to the electrothermal layer 41 by the regulating device 40 is adjustable.

[0076] In this embodiment, as Figure 5 The regulating device 40 applies voltage to the electrothermal layer 41 through the heating circuit 42, causing the electrothermal layer 41 to generate an electrothermal effect, which can directly heat the nanostructure 12. After the nanostructure 12 undergoes a temperature change, it causes a change in the refractive index of the phase change material, thereby achieving the adjustment of the operating wavelength of the metasurface 10.

[0077] In this embodiment, the operating band of the metasurface 10 can be adjusted by adjusting the voltage applied to the electrothermal layer 41, thus reducing the difficulty of adjusting the operating band of the metasurface 10.

[0078] In some embodiments, such as Figure 6 The adjustment device 40' includes a liquid crystal layer 41' filled between the nanostructures 12, and the thickness of the liquid crystal layer 41' along the optical axis is greater than the height of the nanostructures 12 along the optical axis.

[0079] In this embodiment, the birefringence of the liquid crystal layer 41' is determined by its molecular arrangement. When no power is applied, the liquid crystal molecules may have a specific initial arrangement (such as parallel to the substrate). After a voltage is applied, the molecules are tilted or vertically aligned, resulting in the effective refractive index changing continuously with the electric field strength.

[0080] In this embodiment, the birefringence of the liquid crystal layer 41' enables it to change the polarization state of the incident light (such as linear deflection to circular deflection, phase retardation). The molecular alignment direction modulated by the electric field directly affects the direction of the birefringence axis and the amount of phase retardation, thereby achieving active control over the polarization state of the outgoing light.

[0081] In some embodiments, the adjustment device 40' is used to adjust the equivalent refractive index or polarization response at the nanostructure 12. In this embodiment, by using the liquid crystal layer 41' to adjust the equivalent refractive index or polarization response at each nanostructure 12, the operating wavelength of the metasurface 10 can be adjusted.

[0082] In this embodiment, by introducing an electro-optic tuning mechanism, such as a PIN junction, dynamic control of the center wavelength (i.e., the working band) of the metasurface 10 can be achieved, meeting the adaptive wave-locking requirements of multimode lasers. Multi-band filtering switching can be realized on the same optoelectronic chip, breaking through the static characteristic limitations of traditional Bragg gratings.

[0083] In some embodiments, the adjustment device 40' further includes a first electrode layer 42' and a second electrode layer 43' located on both sides of the liquid crystal layer 41', the first electrode layer 42' being located between the substrate 13 and the nanostructure 12, and the voltage applied by the adjustment device 40' to the first electrode layer 42' and the second electrode layer 43' being adjustable.

[0084] In this embodiment, as Figure 6 The regulating device 40' uses the pressure circuit 44' to regulate the voltage between the first electrode layer 42' and the second electrode layer 43', thereby regulating the voltage applied to the liquid crystal layer 41' by the first electrode layer 42' and the second electrode layer 43', so as to change the molecular orientation of the liquid crystal layer 41' and dynamically modulate its equivalent refractive index.

[0085] In this embodiment, after adjusting the voltage applied to the liquid crystal layer 41' by the first electrode layer 42' and the second electrode layer 43', the polarization state conversion of the incident light is achieved by electrically adjusting the birefringence axis direction of the liquid crystal layer 41'.

[0086] In this embodiment, the operating band of the metasurface 10 can be adjusted by adjusting the voltage applied to the first electrode layer 42' and the second electrode layer 43', thus reducing the difficulty of adjusting the operating band of the metasurface 10.

[0087] In some embodiments not shown, the adjustment device (not shown) is used to adjust the structural parameters of the nanostructure 12.

[0088] In this embodiment, by adjusting the structural parameters of the nanostructure 12, the center wavelength (i.e., the working band) of the metasurface 10 can be dynamically adjusted, which meets the adaptive wave-locking requirements of multimode lasers and enables multi-band filtering switching on the same optoelectronic chip, breaking through the static characteristic limitations of traditional Bragg gratings.

[0089] In some embodiments not shown, the structural parameters include at least one of the following parameters: the period of the superstructure unit 11 in which the nanostructure 12 is located, the characteristic size of the nanostructure 12, and the arrangement of the nanostructure 12.

[0090] In this embodiment, changing at least one parameter among the period of the superstructure unit 11 in which the nanostructure 12 is located, the characteristic dimensions (e.g., size and shape) of the nanostructure 12, and the arrangement of the nanostructure 12 can correspondingly change the center wavelength (i.e., the operating band) of the metasurface 10.

[0091] In some embodiments not shown, the substrate 13 is made of an elastic material. In this embodiment, the substrate 13 can be made of an elastic material, which can undergo elastic deformation under external force, thereby changing the position and size of the nanostructure 12 connected to the substrate 13.

[0092] In some embodiments not shown, the force applied to the substrate 13 by the adjustment device is adjustable to drive the substrate 13 to produce elastic deformation.

[0093] In this embodiment, the force applied to the substrate 13 by the adjusting device can be the force generated by the adjusting device squeezing or stretching the substrate 13.

[0094] In this embodiment, the adjustment device applies force directly to the substrate 13, thereby changing at least one of the structural parameters by driving the substrate 13 to elastically deform.

[0095] For example, when the adjusting device does not apply a force to the substrate 13, the cross-sectional shape of the nanostructure 12 is square. After the adjusting device applies a force to the substrate 13, the cross-sectional shape of the nanostructure 12 changes from square to rectangular, thereby changing the feature size of the nanostructure 12.

[0096] Furthermore, when one of the structural parameters of the nanostructure 12 (e.g., the characteristic size of the nanostructure 12) changes, it may simultaneously cause changes in other structural parameters (e.g., the periodicity of the superstructure unit 11).

[0097] In some other embodiments not shown, a deformation layer may be wrapped around the outside of the metasurface 10. The deformation layer is made of a thermally expanding material. Changes in temperature will cause expansion at the deformation layer, thereby causing elastic deformation of the metasurface 10, which in turn allows for adjustment of the structural parameters of the nanostructure 12.

[0098] In some embodiments not shown, the adjustment device is used to adjust the incident angle onto the metasurface 10.

[0099] In this embodiment, by adjusting the incident angle of the metasurface 10, the center wavelength (i.e., the working band) of the metasurface 10 can be dynamically adjusted, which meets the adaptive wave-locking requirements of multimode lasers and enables multi-band filtering switching on the same optoelectronic chip, breaking through the static characteristic limitations of traditional Bragg gratings.

[0100] For example, the metasurface is fixed to the rotating base, and the rotation of the rotating base drives the metasurface 10 to rotate, thereby adjusting the incident angle of the light incident on the metasurface 10.

[0101] In some embodiments, in conjunction with reference Figure 7 As shown, the image sensor 100 includes a plurality of metasurfaces 10, which are cascaded on the light-incident side of the optoelectronic chip 30.

[0102] In this embodiment, as Figure 7 Multiple metasurfaces 10 are sequentially connected to the light-incident side of the optoelectronic chip 30, which can realize the superposition of the filtering function of the metasurfaces 10.

[0103] In some embodiments, the multiple metasurfaces are either separately configured or integrally formed.

[0104] In this embodiment, multiple metasurfaces 10 are manufactured individually and then fixed together by adhesive bonding, enabling the metasurfaces 10 to be replaceable. Since the metasurfaces 10 are periodic structures, the tolerance for bonding is high, and the precision requirements for docking are relatively low.

[0105] In this embodiment, multiple metasurfaces 10 are integrally formed, which can eliminate the need for docking processes between multiple metasurfaces 10.

[0106] In this embodiment, as Figure 8 By cascading multiple metasurfaces 10, a flat-top narrow-band effect is achieved, resulting in metasurface 10 exhibiting both high transmittance and narrow bandwidth. This is significantly better than the bandwidth of a single metasurface 10, which is less than 0.1 nm (e.g., ...). Figure 3 The bandwidth of this solution reaches 1nm (e.g., 0.088nm in the original text). Figure 8 The center wavelength (1.093nm) that can be sensed by the optoelectronic chip 30 reaches 940±0.5nm, thus improving energy utilization.

[0107] Moreover, while still satisfying the narrowband requirement, the energy is more concentrated near the center wavelength, resulting in improved tolerance.

[0108] In addition, the volume increase from cascading multiple metasurfaces 10 is smaller compared to the cascading of traditional Bragg gratings.

[0109] According to another aspect of this utility model, in conjunction with reference to... Figure 9 As shown, an imaging device is also provided, which includes an optical system 200 and an image sensor 100 according to the present invention, wherein the image sensor 100 is located on the image plane of the optical system 200.

[0110] In this embodiment, the optical system 200 is capable of shaping, for example collimating, the emitted light from the light source 300.

[0111] In some embodiments, the optical system 200 and the image sensor 100 are separately configured.

[0112] In this embodiment, the optical system 200 can be a conventional lens or a metasurface. The optical system 200 and the image sensor 100 are set separately, which can reduce the manufacturing difficulty of the imaging device and facilitate the maintenance or replacement of the imaging device.

[0113] In some embodiments, the optical system 200 is integrally formed with the image sensor 100.

[0114] In this embodiment, the optical system 200 and the image sensor 100 are integrally formed, which can eliminate the assembly process between the optical system 200 and the image sensor 100.

[0115] For example, the optical system 200 adopts a metasurface form and is integrally formed with the image sensor 100 (i.e., the Bragg grating) through semiconductor technology, so that the metasurface 10 can simultaneously realize the functions of filtering, beam shaping and polarization control, and can integrate spectral screening and spatial light modulation functions in a single device (i.e., a device composed of the optical system 200 and the image sensor 100).

[0116] For example, such as Figure 9 The imaging device is a transmissive imaging device. The light source 300 and the image sensor 100 are located on both sides of the object being photographed. The light passes through the object and is received by the image sensor 100.

[0117] In a different embodiment not shown, the imaging device may also be a reflective imaging device, i.e., the light source 300 and the image sensor 100 are located on the same side of the object being photographed, and the image sensor 100 receives the reflected light from the surface of the object.

[0118] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0119] The detailed descriptions listed above are merely specific descriptions of feasible implementations of this utility model, and are not intended to limit the scope of protection of this utility model. All equivalent implementations or modifications made without departing from the spirit of this utility model should be included within the scope of protection of this utility model.

Claims

1. An image sensor, characterized in that, include: Optoelectronic chips; A metasurface is located on the light-incident side of the optoelectronic chip. The metasurface is configured as a Bragg grating to transmit incident light in the working band to the optoelectronic chip and reflect incident light in the non-working band. The image sensor also includes an adjustment device for adjusting the operating wavelength of the metasurface.

2. The image sensor as described in claim 1, characterized in that, The metasurface comprises an array of nanostructures made of phase change materials, and the regulating device is used to regulate the temperature at the nanostructures.

3. The image sensor as described in claim 2, characterized in that, The metasurface also includes a substrate, and the adjustment device includes an electrothermal layer located between the substrate and the nanostructure. The voltage applied to the electrothermal layer by the adjustment device is adjustable.

4. The image sensor as described in claim 1, characterized in that, The metasurface includes nanostructures, and the adjustment device includes a liquid crystal layer filled between the nanostructures. The thickness of the liquid crystal layer along the optical axis is greater than the height of the nanostructures along the optical axis. The adjustment device is used to adjust the equivalent refractive index or polarization response at the nanostructures.

5. The image sensor as described in claim 4, characterized in that, The metasurface includes a substrate, and the adjustment device further includes a first electrode layer and a second electrode layer located on both sides of the liquid crystal layer. The first electrode layer is located between the substrate and the nanostructure, and the voltage applied to the first electrode layer and the second electrode layer by the adjustment device is adjustable.

6. The image sensor as claimed in claim 1, characterized in that, The metasurface includes a nanostructure, and the adjustment device is used to adjust the structural parameters of the nanostructure. The structural parameters include at least one of the following: the period of the superstructure unit in which the nanostructure is located, the characteristic size of the nanostructure, and the arrangement of the nanostructure.

7. The image sensor as claimed in claim 1, characterized in that, The metasurface includes a substrate made of an elastic material, and the force applied to the substrate by the adjustment device is adjustable to drive the substrate to produce elastic deformation.

8. The image sensor as claimed in claim 1, characterized in that, The adjustment device is used to adjust the incident angle of the light incident on the metasurface.

9. The image sensor as claimed in claim 1, characterized in that, The image sensor includes antireflective coatings disposed on the light-incident and light-outcident sides of the metasurface. The antireflective coatings include alternating silicon nitride and silicon oxide layers, and the antireflective coatings are integrally formed with the optoelectronic chip.

10. The image sensor as claimed in claim 1, characterized in that, The image sensor includes multiple metasurfaces, which are cascaded on the light-incident side of the optoelectronic chip.

11. The image sensor as claimed in claim 1, characterized in that, The metasurface includes a nanostructure, which is asymmetrical with respect to a first axis and symmetrical with respect to a second axis perpendicular to the first axis. Both the first and second axes are perpendicular to the optical axis of the metasurface.

12. An imaging device, characterized in that, The imaging device includes an optical system and an image sensor as described in any one of claims 1-11, wherein the image sensor is located on the image plane of the optical system, and the optical system and the image sensor are either separately configured or integrally formed.

Images