Spectrometer based on metasurface lens and electronic equipment

Abstract

The invention discloses a spectrometer based on a metasurface lens and electronic equipment. The spectrometer comprises an optical fiber interface, the metasurface lens and a photoelectric detector. The fiber interface is used for connecting fibers; the metasurface lens is used for guiding, splitting and dispersing the incident light of different wavelengths accessed from the optical fiber interface, and focusing the incident light of different wavelengths to different positions of a detection plane; a photodetector is configured to receive light from the metasurface lens at the detection plane. The optical fiber interface is connected with the optical fiber, and optical signals of all wavebands can be received only through one interface; compared with the prior art, multi-channel, broadband and high-resolution spectral measurement can be realized only by adopting one metasurface lens, the complexity of a system is greatly reduced, the size of the whole spectrograph is greatly reduced, the requirements of miniaturization, broadband, high resolution and high sensitivity are met, and the cost and the process difficulty are also reduced.

Description

Technical Field

[0001] The present application relates to the field of spectral detection technology, and in particular to a spectrometer and electronic equipment based on a metasurface lens. Background Art

[0002] As a nondestructive testing method, spectral detection technology is widely used in environmental monitoring, agricultural production, food safety, and other fields. However, different fields have different requirements for measurement bands. For example, vegetation and crop testing requires a measurement band of 400nm to 1000nm, while water quality testing may require a wider measurement band of 200nm to 1000nm. Spectral detection instruments are continuously developing towards wide bands, miniaturization, high resolution, and high sensitivity.

[0003] However, conventional broadband multi-channel spectrometers typically require multiple optical input ports, each connected to a prism or grating device operating in different wavelength bands. The optical signal passes through the prism or grating array, undergoes dispersion and splitting, and is then focused by a lens before reaching the photodetector array. This results in complex multi-channel spectrometer systems, a large number of components, and difficulty miniaturizing the entire system. As spectral detection technology advances toward miniaturization, wide bandwidth, high resolution, and high sensitivity, existing technologies are no longer able to meet practical needs. Summary of the Invention

[0004] The purpose of this application is to provide a spectrometer and electronic equipment based on a metasurface lens.

[0005] To achieve one of the above-mentioned application objectives, an embodiment of the present application provides a spectrometer, comprising:

[0006] Optical fiber interface, used to connect optical fiber;

[0007] A metasurface lens is used to guide, split, and disperse incident light of different wavelengths input from the optical fiber interface, and focus the incident light of different wavelengths to different positions on the detection plane;

[0008] A photodetector is configured to receive light from the metasurface lens at the detection plane.

[0009] As a further improvement of an embodiment of the present application, the metasurface lens includes a substrate and n nanocolumn array units provided on the substrate, wherein the n nanocolumn array units are arranged side by side along a first direction according to serial numbers from 1 to n, and each of the nanocolumn array units extends along a second direction perpendicular to the first direction; the detection plane includes n areas, and the i-th nanocolumn array unit is configured to selectively detect light with a wavelength range of λ i ~λ i+1The light in the detection plane is guided, split, dispersed, and focused to the i-th area of ​​the detection plane, where n≥2, i=1,...,n.

[0010] As a further improvement to an embodiment of the present application, each of the nanocolumn array units includes a plurality of the nanocolumns, and a coordinate system is established with the center of each of the nanocolumn array units as the coordinate origin, the first direction as the X-axis, the second direction as the Y-axis, and the direction perpendicular to the surface of the substrate where the nanocolumns are provided as the Z-axis. The plane where the X-axis and the Y-axis lie is the surface of the substrate where the nanocolumns are provided, and the Z-axis direction is the direction from the substrate toward the nanocolumns.

[0011] The phase of the nanopillars for:

[0012]

[0013] Wherein, λ is the wavelength of the incident light, θ is the incident angle of the incident light on the metasurface lens, x and y are the x-coordinate and y-coordinate of the center of the nanocolumn, f is the focal length of the nanocolumn, and f x 、f y 、f z are the focal length components of the nanocolumn in the X-axis, Y-axis, and Z-axis directions, respectively.

[0014] As a further improvement of an embodiment of the present application, f y ≤f x ≤3f y .

[0015] As a further improvement of an embodiment of the present application, in different nanorod array units, at least one of the material, shape, height, period, and arrangement of the nanorods is different.

[0016] As a further improvement of one embodiment of the present application, the metasurface lens is arranged at an angle to the photodetector.

[0017] As a further improvement of an embodiment of the present application, the spectrometer further includes a light shielding member, which is located to shield stray light.

[0018] As a further improvement of an embodiment of the present application, the photodetector is a CMOS detector.

[0019] As a further improvement of one embodiment of the present application, the spectrometer further includes a reflector, which is configured to reflect incident light of different wavelengths input from the optical fiber interface and then reach the metasurface lens.

[0020] In order to achieve one of the above-mentioned application purposes, an embodiment of the present application further provides an electronic device, including the spectrometer as described above.

[0021] Compared with the existing technology, the spectrometer of the present application has the following beneficial effects: it uses an optical fiber interface to connect optical fibers, and only one interface is needed to receive optical signals of all bands; based on the metasurface lens, the phase of the optical signal is controlled by the subwavelength structure etched on the planar optical medium material, and the deflection, dispersion and focusing of the light wave are realized, that is, only one metasurface lens is used to achieve multi-channel, wide-band, high-resolution spectral measurement, which greatly reduces the complexity of the system. Moreover, the metasurface lens is a flat optical element, and its size is greatly reduced compared to the traditional curved lens, which greatly reduces the overall volume of the spectrometer, while meeting the requirements of miniaturization, wide band, high resolution and high sensitivity, and also reducing the cost and process difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a cross-sectional schematic diagram of the spectrometer of Example 1 of the present application;

[0023] Figure 2 1 is a schematic top view of the metasurface lens in the spectrometer of Example 1 of the present application;

[0024] Figure 3 2 is a schematic cross-sectional view of the metasurface lens in the spectrometer of Example 1 of the present application in the XZ plane;

[0025] Figure 4 1 is a schematic top view of the metasurface lens in the spectrometer of Example 1 of the present application;

[0026] Figure 5 It is a cross-sectional schematic diagram of the spectrometer of Example 2 of the present application.

[0027] Description of reference numerals:

[0028] 10. Spectrometer; 1. Fiber optic interface; 2. Metasurface lens; 21. Substrate; 22. Nanopillar array unit; 221. Nanopillar; 3. Photodetector; 4. Housing; 5. Shading element; 51. Shading component; 6. Reflector. DETAILED DESCRIPTION

[0029] The present application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings.

[0030] In the various figures of the present application, for the sake of convenience, some dimensions of structures or parts are exaggerated relative to other structures or parts, and therefore, are only used to illustrate the basic structure of the subject matter of the present application.

[0031] It should be understood that although the terms "first", "second", etc. may be used in this document to describe various elements, structures or parameters, these described objects should not be limited by these terms. These terms are only used to distinguish these described objects from each other.

[0032] Existing spectrometers usually use cascades of slits, collimators, prisms or gratings, and metasurface lenses, but still have a large number of system components, which has limited potential for reducing the size of the spectrometer. The manufacturing process is complex and cannot simultaneously meet the requirements of miniaturization, high resolution, and high sensitivity, and the cost is relatively high.

[0033] Multi-channel spectrometers also require slit arrays, collimator arrays, gratings, or prism arrays to meet wide-band requirements. While maintaining resolution, the spectrometer will be larger, even doubled in size. Furthermore, such arrayed optical components increase the spectrometer's complexity and cost.

[0034] A metasurface lens is a planar optical element based on metasurface technology that modulates the phase, amplitude, and polarization of light waves through subwavelength structures. The pattern on it is composed of periodically or aperiodically arranged subwavelength structural units (such as nanopillars and nanoantennas).

[0035] Example 1

[0036] Ginseng Figure 1 As shown, this embodiment provides a spectrometer 10 based on a metasurface lens, including a fiber optic interface 1, a metasurface lens 2 and a photodetector 3.

[0037] The optical fiber interface 1 is used to connect an optical fiber, thereby introducing an incident light signal generated by an external light source, a sample or a detector into the spectrometer 10 from an external optical path.

[0038] The metasurface lens 2 is used to guide, split, and disperse the incident light of different wavelengths input from the optical fiber interface 1, and focus the incident light of different wavelengths to different positions on the detection plane.

[0039] The photodetector 3 is configured to receive light from the metasurface lens 2 at a detection plane to achieve detection imaging.

[0040] The spectrometer 10 of the present application uses an optical fiber interface 1 to connect to the optical fiber, and only one interface is needed to receive optical signals of all bands; based on the metasurface lens 2, the phase of the optical signal is controlled by a subwavelength structure etched on a planar optical medium material, thereby realizing deflection, dispersion, and focusing of the light wave. That is, only one metasurface lens 2 is used to achieve multi-channel, wide-band, and high-resolution spectral measurement, which greatly reduces the complexity of the system. Moreover, the metasurface lens 2 is a planar optical element, and its size is greatly reduced compared to traditional curved lenses, which greatly reduces the overall volume of the spectrometer 10, while meeting the requirements of miniaturization, wide-band, high-resolution, and high-sensitivity, and also reducing costs and process difficulty.

[0041] Furthermore, the metasurface lens 2 allows the size of the lens to be increased to a certain extent without increasing the overall size of the spectrometer 10. Since the resolution of a focusing lens is proportional to its numerical aperture, the numerical aperture of the metasurface lens 2 can be increased by increasing its size, thereby improving the resolution of the spectrometer 10.

[0042] The spectrometer 10 includes a housing 4 , and the optical fiber interface 1 is located on the housing 4 .

[0043] The optical fiber interface 1 is preferably connected to a multimode optical fiber, which has high coupling efficiency, low latency, allows transmission power up to 1W, and has high compatibility.

[0044] See Figures 2 to 4 The metasurface lens 2 includes a substrate 21 and n nanocolumn array units 22 provided on the substrate 21. The n nanocolumn array units 22 are arranged side by side along a first direction according to serial numbers from 1 to n, and each nanocolumn array unit 22 extends along a second direction perpendicular to the first direction.

[0045] The widths of different nanorod array units 22 may be the same or different, and may be specifically designed according to the light spot conditions on the detection plane.

[0046] Since the incident light enters different nanorod array units 22 at different angles, the larger the incident angle, the more likely crosstalk will occur on the detection plane. By designing different widths of different nanorod array units 22, crosstalk between different channels can be avoided.

[0047] The substrate 21 may be a glass substrate 21 or a substrate made of other commonly used substrate materials.

[0048] The detection plane includes n areas, and the i-th nanorod array unit 22 is configured to selectively guide, split, and disperse light within a wavelength range of λi to λi+1 and focus it on the i-th area of ​​the detection plane, where n≥2, i=1,...,n.

[0049] That is to say, the n areas of the detection plane correspond one-to-one to the n nanocolumn array units 22 of the metasurface lens 2. Each nanocolumn array unit 22 corresponds to a channel, guiding, splitting, and dispersing light within a specific wavelength range, focusing it on a specific area of ​​the detection plane. The photodetector 3 detects light with a wavelength within the specific wavelength range within the specific area and outputs the corresponding spectrum.

[0050] In this way, wide-band multi-channel spectral measurement can be achieved through n nanorod array units 22, which greatly increases the wavelength range of spectral detectability and is suitable for different application scenarios.

[0051] The wavelength bands targeted by the n nanorod array units 22 may be continuous, discontinuous or non-sequential.

[0052] Incident light enters the spectrometer 10 from the optical fiber interface 1 and impinges on the metasurface lens 2. The different nanopillar array units 22 within the metasurface lens 2 respond only to wavelengths within their corresponding ranges. Incident light signals within the corresponding wavelength ranges pass through the corresponding nanopillar array unit 22. The phase of the incident light signal is precisely controlled by the nanopillar array unit 22, and then illuminates the target surface of the photodetector 3 along a set path, thereby illuminating a specific area of ​​the detector target surface and achieving wide-band, high-throughput, and high-resolution spectral measurements. Incident light signals outside the corresponding wavelength range cannot pass through the nanopillar array unit 22, and even if they do, they cannot propagate to the target surface of the photodetector 3.

[0053] For example, if the design wavelength range of the spectrometer 10 is 200 to 1000 nm. The wavelength range is divided into 7 bands, that is, n=7, and each band covers a wavelength range of 100 nm. The metasurface lens 2 includes 7 nanocolumn array units 22, and the 7 nanocolumn array units 22 are arranged side by side along the first direction. The first nanocolumn array unit 22 guides, splits, and disperses light in the wavelength range of 200 to 300 nm, and focuses it on the first area of ​​the detection plane. By analogy, the seventh nanocolumn array unit 22 guides, splits, and disperses light in the wavelength range of 900 to 1000 nm, and focuses it on the seventh area of ​​the detection plane. It can be understood that the above-mentioned wavelength ranges and the values ​​of n are only exemplary, and the present application is not limited in this respect.

[0054] See Figures 3 and 4 Each nanopillar array unit 22 includes a plurality of nanopillars 221. The nanopillars 221 change the polarization, amplitude, phase, and propagation mode of the incident light, thereby guiding, splitting, dispersing, and focusing the light, thereby regulating the phase change of the light emitted from the metasurface lens 2.

[0055] See Figures 2 to 4 A coordinate system is established with the center of each nanopillar array unit 22 as the coordinate origin, the first direction as the X-axis, the second direction as the Y-axis, and the direction perpendicular to the surface of the substrate 21 on which the nanopillars 221 are disposed as the Z-axis. The plane of the X-axis and the Y-axis is the surface of the substrate 21 on which the nanopillars 221 are disposed, and the Z-axis is the direction from the substrate 21 toward the nanopillars 221. The X-axis, Y-axis, and Z-axis conform to the right-hand rule. The first direction is also the non-dispersive direction of the metasurface lens 2, and the second direction is the dispersive direction of the metasurface lens 2.

[0056] Phase of nanorod 221 for:

[0057]

[0058] Where λ is the wavelength of the incident light, θ is the incident angle of the incident light on the metasurface lens 2, x and y are the x-coordinate and y-coordinate of the center of the nanorod 221, f is the focal length of the nanorod 221, and f x 、f y 、f z are the focal length components of the nanorod 221 in the X-axis, Y-axis, and Z-axis directions, respectively.

[0059] According to the above phase formula, the size of the nanorod 221 can be set to perform fine phase control on the metasurface lens 2, thereby realizing dispersion, splitting, and focusing control of the light beam, so that the light output from the multimode optical fiber can be directly received, thus eliminating the need for slits and collimation devices; after receiving the optical signal from the multimode optical fiber, the metasurface lens 2 can simultaneously control the light in the dispersion direction and the non-dispersion direction, while ensuring higher-resolution measurement and avoiding crosstalk between optical signals of different channels.

[0060] in,

[0061] is the dispersion spectroscopic phase,

[0062] Φ2 is the focusing phase in the dispersion direction,

[0063] Φ3 is the focusing phase in the non-dispersive direction,

[0064] In this way, the phase formula of the nanorod 221 can achieve splitting, dispersion, and focusing effects, so that wide-band, multi-channel, high-resolution spectral measurement can be achieved using only the metasurface lens 2, greatly reducing the number of components in the spectrometer 10, thereby reducing the complexity and cost of the spectrometer 10.

[0065] Among them, f y ≤f x ≤3f y In this way, the arrangement period of the nanopillars 221 in the nanopillar array unit 22 along the Y-axis direction can be relaxed, that is, the spacing between the nanopillars 221 along the Y-axis direction can be increased, thereby reducing the difficulty of processing the metasurface lens 2.

[0066] The extending direction of the nanorods 221 may be parallel to the Z axis, or may have a certain angle with the Z axis.

[0067] See Figures 3 and 4 In different nanorod array units 22 , at least one of the material, shape, height, period, number, and arrangement of the nanorods 221 is different.

[0068] In practical applications, the material, shape, height, period, and arrangement of the nanopillars 221 in different nanopillar array units 22 can be specifically set according to the different wavelength ranges of the incident light corresponding to the nanopillar array units 22, so that light of different wavelength bands can be guided, split, dispersed, and focused more accurately.

[0069] For example, when the wavelength range of the incident light is the visible light band, the nanopillars 221 in the nanopillar array unit 22 can be made of TiO2 material; when the wavelength range of the incident light is the infrared band, the nanopillars 221 in the nanopillar array unit 22 can be made of Si material; when the wavelength range of the incident light is the ultraviolet band, the nanopillars 221 in the nanopillar array unit 22 can be made of HfO2 material.

[0070] In another embodiment, the shapes and heights of the nanopillars 221 in different nanopillar array units 22 may be different. Specifically, the cross-sectional shape of the nanopillars 221 may be circular, square, elliptical, or an irregular geometric shape.

[0071] In another embodiment, the periods and arrangements of the nanorods 221 in different nanorod array units 22 may be different, thereby improving the guiding and focusing effects on light of different wavelength bands.

[0072] Specifically, the arrangement of the nanorods 221 includes but is not limited to a tetragonal lattice arrangement and a hexagonal lattice arrangement.

[0073] See Figure 1 In this embodiment, the metasurface lens 2 is arranged at an angle to the photodetector 3. The specific angle can be adjusted based on the size of the photodetector 3, the wavelength range and resolution of the spectrometer 10. By arranging the metasurface lens 2 at an angle to the photodetector 3, the resolution of the spectrometer 10 can be improved within a certain measurement wavelength range.

[0074] See Figure 1 In one embodiment, the spectrometer 10 further includes a light shield 5 for shielding stray light. While the metasurface lens 2 efficiently focuses, it introduces stray light. Spatial filtering by the light shield 5 suppresses stray light, thereby improving the signal-to-noise ratio.

[0075] Specifically, in this embodiment, the shading member 5 is a shading component 51 disposed in the housing 4 , and the shading component 51 is disposed between the metasurface lens 2 and the photodetector 3 , and is configured to suppress stray light introduced by the metasurface lens 2 .

[0076] The light shielding member 5 may specifically be a light-proof sheet, a light-reducing sheet or a filter sheet.

[0077] In other embodiments, the light shielding member 5 may also be configured as a light absorbing layer coated on the inner wall of the housing 4 .

[0078] In this embodiment, the photodetector 3 is a CMOS detector. The CMOS detector can not only detect the intensity of light at different positions on the detection plane and convert it into an electrical signal to obtain a spectrum, but also eliminate stray light and light outside the detection band. It also has a high resolution, thereby improving the resolution of the spectrometer 10.

[0079] Of course, in other embodiments, the photodetector 3 may be a photoelectric detection element in other forms, such as a CCD.

[0080] An embodiment of the present application further provides an electronic device, including the spectrometer 10 described above.

[0081] The electronic device can specifically be a desktop computer, a server computer, a laptop or netbook computer, a mobile device (such as a tablet computer, a cellular phone, a smart phone, a notepad computer, a mobile station), a wearable device (such as glasses, a watch), an entertainment device (such as an entertainment appliance, a set-top box communicatively coupled to a display device, a game console), a television or other display device, a car computer, etc.

[0082] Example 2

[0083] Ginseng Figure 5 As shown, this embodiment also provides a spectrometer 10 based on a metasurface lens.

[0084] Similar to the previous embodiment 1, the spectrometer 10 also includes a fiber optic interface 1, a metasurface lens 2 and a photodetector 3.

[0085] On this basis, the spectrometer 10 of this embodiment is basically the same as the previous embodiment 1, and the only difference between the two is that the spectrometer also includes a reflector 6, which is configured to reflect the incident light of different wavelengths input from the optical fiber interface 1 and then reach the metasurface lens 2.

[0086] The following describes only the technical contents related to the differences. The remaining technical contents other than the differences are exactly the same as those in the previous embodiment 1 and will not be repeated here.

[0087] Specifically, in this embodiment, after the incident light is introduced into the spectrometer 10 from the optical fiber interface 1, it reaches the reflector 6, and after being reflected by the reflector 6, it reaches the metasurface lens 2. After the metasurface lens 2 guides, splits, and disperses the incident light of different wavelengths, it is focused on different positions of the detection plane. The photodetector 3 receives the light from the metasurface lens 2 at the detection plane to realize detection imaging.

[0088] By disposing the reflector 6 , the direction of the incident light can be adjusted, thereby reducing the volume of the spectrometer 10 .

[0089] In summary, the spectrometer 10 of the present application uses an optical fiber interface 1 to connect to the optical fiber, and only one interface is needed to receive optical signals of all bands; based on the metasurface lens 2, the phase of the optical signal is controlled by a subwavelength structure etched on a planar optical medium material, thereby realizing deflection, dispersion, and focusing of the light wave. That is, only one metasurface lens 2 is used to achieve multi-channel, wide-band, and high-resolution spectral measurement, which greatly reduces the complexity of the system. Moreover, the metasurface lens 2 is a planar optical element, and its size is greatly reduced compared to traditional curved lenses, which greatly reduces the overall volume of the spectrometer 10, while meeting the requirements of miniaturization, wide-band, high-resolution, and high-sensitivity, and also reducing costs and process difficulty.

[0090] The above describes in detail the structure, features and effects of the present application based on the embodiments shown in the accompanying drawings. The above is only a preferred embodiment of the present application, but the present application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of the present application, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present application.

Claims

1. A spectrometer, characterized in that: include: Optical fiber interface, used to connect optical fiber; A metasurface lens is used to guide, split, and disperse incident light of different wavelengths input from the optical fiber interface, and focus the incident light of different wavelengths to different positions on the detection plane; A photodetector is configured to receive light from the metasurface lens at the detection plane.

2. The spectrometer according to claim 1, wherein The metasurface lens includes a substrate and n nanocolumn array units disposed on the substrate, wherein the n nanocolumn array units are arranged side by side along a first direction according to serial numbers from 1 to n, and each of the nanocolumn array units extends along a second direction perpendicular to the first direction; the detection plane includes n areas, and the i-th nanocolumn array unit is configured to selectively detect light with a wavelength range of λ i ~λ i+1 The light in the detection plane is guided, split, dispersed, and focused to the i-th area of ​​the detection plane, where n≥2, i=1,...,n.

3. The spectrometer according to claim 2, characterized in that Each of the nanopillar array units includes a plurality of nanopillars, and a coordinate system is established with the center of each nanopillar array unit as a coordinate origin, the first direction as an X-axis, the second direction as a Y-axis, and a direction perpendicular to the surface of the substrate on which the nanopillars are provided as a Z-axis. The plane where the X-axis and the Y-axis lie is the surface of the substrate on which the nanopillars are provided, and the Z-axis direction is a direction from the substrate toward the nanopillars. The phase of the nanopillars for: Wherein, λ is the wavelength of the incident light, θ is the incident angle of the incident light on the metasurface lens, x and y are the x-coordinate and y-coordinate of the center of the nanocolumn, f is the focal length of the nanocolumn, and f x 、f y 、f z are the focal length components of the nanocolumn in the X-axis, Y-axis, and Z-axis directions, respectively.

4. The spectrometer according to claim 3, characterized in that f y ≤f x ≤3f y 。 5. The spectrometer according to claim 2, characterized in that In different nanorod array units, at least one of the material, shape, height, period, and arrangement of the nanorods is different.

6. The spectrometer according to claim 1, characterized in that The metasurface lens is arranged at an angle to the photodetector.

7. The spectrometer according to claim 1, characterized in that A light shielding member is also included, and the light shielding member is used to shield stray light.

8. The spectrometer according to claim 1, wherein The photodetector is a CMOS detector.

9. The spectrometer according to claim 1, wherein It also includes a reflector, which is configured to reflect incident light of different wavelengths input from the optical fiber interface and then reach the metasurface lens.

10. An electronic device, characterized in that: Comprising the spectrometer according to any one of claims 1 to 9.

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