A miniature spectrometer

Abstract

The application discloses a kind of microspectrometer, including graphene belt, top mirror, bottom mirror, transparent electrode, photoelectric conversion layer, column, substrate dielectric layer, circuit control module and data acquisition and analysis system, wherein, column is perpendicular to substrate dielectric layer, and top mirror by one-dimensional photonic crystal is hung on column by double-layer graphene belt;Substrate dielectric layer is provided with transparent electrode, and photoelectric conversion layer is integrated on transparent electrode, and one-dimensional photonic crystal is grown on photoelectric conversion layer to form bottom mirror;Circuit control module is connected with the electrode on transparent electrode and graphene belt;Data acquisition and analysis system is connected with the electrode at the both ends of photoelectric conversion layer and the electrode on graphene belt, and the design can realize selective absorption to different wavelength light to realize spectrum analysis.

Description

Technical Field

[0001] This invention relates to the field of miniature spectrometer design, and more specifically to a miniature spectrometer. Background Technology

[0002] Spectrometers characterize the spectra of substances, enabling analysis of their composition and structure. They are widely used analytical tools in scientific research and industrial applications. In particular, with the development of trace analysis and intelligent, portable devices, the demand for small-sized, low-cost, and high-performance integrable miniature spectrometers is increasing. Integrable miniature spectrometers have significant application prospects in health monitoring using wearable devices, food safety and environmental monitoring based on handheld devices, and remote sensing imaging based on unmanned aerial vehicles (UAVs).

[0003] Traditional benchtop spectrometers are typically constructed from large and expensive dispersive elements, requiring a large dispersion space to unfold the spectrum in the spatial domain. This fails to meet the urgent needs of modern technology for real-time, convenient, and accurate spectral analysis. To reduce the size of spectrometers and improve performance, various miniature spectrometers based on different principles have been proposed, such as dispersive grating type, narrowband filter type, Fourier transform type, and computational reconstruction type miniature spectrometers. However, spatial dispersive miniature spectrometers mainly separate and detect light in space through strongly dispersive media or detector arrays. Due to the limitation of dispersion intensity, further miniaturization of the spectrometer is difficult, and integration with imaging equipment is challenging, resulting in poor spatial resolution.

[0004] Fabry-Pérot filters based on microelectromechanical systems (MEMS) technology have also been used to fabricate tunable optical filters. These filters typically use voltage or other methods to adjust the resonant wavelength of the Fabry-Pérot cavity, thereby achieving selective reflection or transmission of light. This structure does not require a dispersive element and can theoretically be used in miniature spectrometers. However, Fabry-Pérot filters based on traditional MEMS technology are limited by mechanical structure, and their size is difficult to further compress. Moreover, in traditional MEMS Fabry-Pérot filters, when external force is applied, the cavity mirrors of the Fabry-Pérot cavity will undergo non-uniform deformation due to stress, which will increase the half-width at half-maximum (WHM) of the Fabry-Pérot filter and reduce the resolution of the corresponding spectrometer [e.g., Mao H, Silva KD, Martyniuk M, et al. MEMS-based tunable Fabry–Perot filters for adaptive multispectral thermal imaging[J]. Journal of MicroelectromechanicalSystems, 2016, 25(1):227-235.]. Recently, graphene micro- and nanomechanical applications have attracted researchers' attention. Graphene possesses ultrathin thickness (atomic layer distance of approximately 0.335 nm), superior mechanical properties (Young's modulus can reach 1 TPa, and it can withstand strains of up to 20%), and unique optoelectronic properties (carrier mobility can reach 20,000 cm⁻¹). 2 V -1 s -1 Graphene is an ideal candidate material for micro- and nano-electro-mechanical systems (MEMS and NEMS). Xuge Fan et al. used these excellent characteristics of graphene to design an accelerometer with a suspended mass. Its size is two orders of magnitude smaller than that of the most advanced silicon accelerometer, and it has extremely high sensitivity and response speed, which has attracted widespread attention from researchers. Summary of the Invention

[0005] This invention provides a time-resolved, spatially resolved, image-enabled, and integrable miniature spectrometer. It incorporates graphene microelectromechanical systems (MEMS) into the design of the miniature spectrometer, utilizing a bilayer graphene tape to suspend a DBR mirror, forming a one-dimensional photonic crystal optical microcavity with an air-defect layer. Under the influence of a driving voltage, the graphene tape undergoes elastic deformation, allowing for the modulation of the cavity length of the microcavity's defect layer, the resonant frequency of the microcavity, and the resonant absorption peak of the photoelectric conversion layer. This enables selective absorption of light at different wavelengths, thereby achieving spectral analysis. In particular, this structure is a one-dimensional planar structure, which does not affect the light propagation angle and focusing characteristics. Combined with a high-speed camera, it can achieve time-resolved and spatially resolved spectral imaging, simultaneously displaying the spatiotemporal and spectral information of the luminescent material. This spectrometer has broad application prospects in fields such as micro-intelligent devices, wearable devices, and biomedical systems. It effectively solves the technical problems of existing miniature spectrometers, such as difficulty in extreme miniaturization, complex structure, poor spectral resolution, and difficulty in achieving spectral imaging.

[0006] The present invention is achieved by at least one of the following technical solutions.

[0007] A miniature spectrometer includes a graphene microelectromechanical system-photonic crystal composite structure, a circuit control module, and a data acquisition and analysis system. The graphene microelectromechanical system-photonic crystal composite structure includes a substrate dielectric layer, a transparent electrode, a pillar, a graphene strip, and a top mirror. The transparent electrode and the pillar are disposed on the substrate dielectric layer, and the top mirror is suspended from the pillar via a bilayer graphene strip. A photoelectric conversion layer is integrated on the transparent electrode, and a one-dimensional photonic crystal is grown on the photoelectric conversion layer to form the bottom mirror. The circuit control module is connected to the transparent electrode and the electrodes on the graphene strip, and is used to apply a voltage between the bilayer graphene strip and the transparent electrode. The data acquisition and analysis system is connected to the electrodes at both ends of the photoelectric conversion layer and the electrodes on the graphene strip, and is used to monitor changes in the photocurrent in the photoelectric conversion layer and changes in the resistance in the graphene strip.

[0008] Furthermore, the structure of a one-dimensional photonic crystal is as follows: A and B are periodically arranged silicon (Si) and silicon dioxide (SiO2), and C is an air defect layer. The number of cycles.

[0009] Furthermore, the thickness of the periodically arranged Si and SiO2 is one-quarter of the center wavelength of the incident spectrum, and the length and width range from 1 μm to 100 μm.

[0010] Furthermore, A and B are arranged alternately to form two distributed Bragg reflectors, namely DBR mirrors.

[0011] Furthermore, the photoelectric conversion layer is indium gallium arsenide (InGaAs). 0.52 Ga 0.48 As), its thickness is within ±20% of 10μm.

[0012] Furthermore, the data acquisition and analysis system is used to monitor changes in photocurrent in the photoelectric conversion layer and changes in resistance in the bilayer graphene strip.

[0013] Furthermore, the circuit control module outputs an adjustable DC voltage.

[0014] Furthermore, the circuit control module outputs an alternating voltage with a frequency close to the natural vibration frequency of the top mirror.

[0015] Furthermore, the substrate dielectric layer is indium phosphide (InP).

[0016] Furthermore, the graphene microelectromechanical system-photonic crystal composite structure, microscope, and high-speed camera constitute an image-capable miniature spectrometer. The sample to be tested is placed between a broadband light source and the objective lens of the microscope. The light emitted by the broadband light source is absorbed by the sample to generate different wavelength spectra. When the spectra to be tested are focused by the objective lens of the microscope and incident on the graphene microelectromechanical system-photonic crystal composite structure, the incident spectrum is separated by time and then imaged on the high-speed camera.

[0017] Compared with existing technologies, the beneficial effects of the present invention are as follows:

[0018] This invention introduces graphene microelectromechanical systems (MEMS) into the design of a miniature spectrometer. A one-dimensional photonic crystal optical microcavity with an air-defect layer is constructed using a bilayer graphene belt with suspended DBR mirrors. The cavity length variation of the photonic crystal optical microcavity is entirely determined by the deformation of the graphene, while the deformation of the mirror itself is minimal, ensuring excellent consistency of the microcavity's resonance peaks. By utilizing the electric field or periodic driving force applied to the graphene, the incident spectrum is unfolded in the time domain according to wavelength, thus realizing a time-resolved miniature spectrometer. This miniature spectrometer has a size on the micrometer scale, a spectral resolution on the nanometer scale, a time resolution on the sub-millisecond scale, a wide measurement bandwidth, and small spectral reconstruction error. In particular, this one-dimensional planar structure does not affect the light propagation angle and focusing characteristics. Combined with imaging devices such as microscopes and high-speed cameras, it can also achieve time-resolved and spatially resolved hyperspectral imaging, simultaneously displaying the spatiotemporal and spectral information of luminescent substances. This miniature spectrometer has a simple structure, its manufacturing process is compatible with mature semiconductor technology, and it is easy to integrate with chips. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a miniature spectrometer according to an embodiment of the present invention;

[0020] Figure 2 For the present invention Figure 1 The diagram shows the result of the center wavelength of the absorption peak in the structure changing with the driving voltage. The inset shows the result of the cavity length of the microcavity changing with the driving voltage.

[0021] Figure 3 For the present invention Figure 1 The diagram shows the variation of the center wavelength of the absorption peak in the structure shown over time. The upper left inset shows the variation of the cavity length of the microcavity over time; the lower right inset shows the variation of the displacement of the top mirror over time.

[0022] Figure 4 This is a schematic diagram of another structure of a miniature spectrometer according to an embodiment of the present invention;

[0023] Figure label:

[0024] 1-Substrate dielectric layer, 2-Transparent electrode, 3-Photoelectric conversion layer, 4-Bottom mirror, 5-Column, 6-Graphene strip, 7-Top mirror, 8-Electrode, 9-Circuit control module, 10-Data acquisition and analysis system, 11-Broadband light source, 12-Microscope objective lens, 13-Graphene microelectromechanical system-photonic crystal composite structure, 14-Microscope, 15-High-speed camera. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0026] An embodiment of the present invention provides a miniature spectrometer, such as... Figure 1 As shown, it includes a graphene microelectromechanical system-photonic crystal composite structure 13, a circuit control module 9, and a data acquisition and analysis system 10. The graphene microelectromechanical system-photonic crystal composite structure 13 includes a substrate dielectric layer 1, a transparent electrode 2, a photoelectric conversion layer 3, a bottom mirror 4, a pillar 5, a graphene strip 6, a top mirror 7, and an electrode 8.

[0027] This miniature spectrometer is mainly composed of a graphene microelectromechanical system-photonic crystal composite structure. A pillar 5 is vertically mounted on a substrate dielectric layer 1. A top mirror 7 is suspended from the pillar 5 via a double-layer graphene strip 6, forming the graphene microelectromechanical system. A transparent electrode 2 is mounted on the substrate dielectric layer 1, and a photoelectric conversion layer 3 is integrated on the transparent electrode 2. A one-dimensional photonic crystal is grown on the photoelectric conversion layer 3 to form a bottom mirror 4. The photoelectric conversion layer 3 is integrated between the bottom mirror 4 and the transparent electrode 2, forming a photodetector. A circuit control module 9 is connected to the transparent electrode 2 and the electrode 8 on the graphene strip, used to apply voltage between the double-layer graphene strip and the transparent electrode. A data acquisition and analysis system 10 is connected to the electrodes at both ends of the photoelectric conversion layer and the electrode on the graphene strip, used to monitor changes in the photocurrent in the photoelectric conversion layer and changes in the resistance in the graphene strip.

[0028] A micro / nanomechanical system is constructed using graphene strips and a top mirror, forming a one-dimensional photonic crystal optical microcavity with an air-defect layer, together with a bottom mirror. By applying a driving voltage to the graphene strip, the cavity length of the air-defect layer is adjusted, enabling modulation of the optical microcavity's resonant wavelength, the resonant absorption peak of the photoelectric conversion layer, and the microcavity's transmission peak. Unlike traditional microelectromechanical systems (MEMS) optical microcavities, the extremely thin graphene strip only deforms under external force, while the top mirror itself deforms very little. This improves the microcavity's parallelism, reduces the full width at half maximum (FWHM) of the transmission or resonant absorption peaks, and enhances the spectral resolution of the miniature spectrometer. Simultaneously, the extremely thin graphene strip allows for greater deformation, increasing the spectral measurement bandwidth of the miniature spectrometer. Furthermore, because this structure is one-dimensional and planar, it does not affect the light propagation angle or focusing characteristics. Separating the incident spectrum over time and projecting it onto a high-speed camera allows for temporally and spatially resolved spectral imaging, simultaneously displaying the spatiotemporal and spectral information of the luminescent material, thus enabling an imaging spectrometer.

[0029] As one embodiment, the thickness D of the bilayer graphene strip g 0.67nm, width W g 1.0 μm, Young's modulus E g The internal stress σ0 is 0.0 MPa, and the groove width (distance between the edge of the column and the top mirror) is L. g It is 6.0 μm.

[0030] The electrodes on the bilayer graphene strip and the electrodes at both ends of the photoelectric conversion layer are connected to a data acquisition and analysis system. During the stretching process of the graphene strip, its resistance changes significantly. Monitoring the change in resistance within the graphene strip allows for the monitoring of graphene deformation and top mirror displacement. Real-time detection of the photocurrent in the photoelectric conversion layer yields the changes in photocurrent with either the driving voltage or the vibration time of the top mirror.

[0031] The photoelectric conversion layer 3 can convert the optical signal from the resonant absorption peak into an electrical signal, achieving selective absorption of the spectrum. As one embodiment, the photoelectric conversion layer 3 is In... 0.52 Ga 0.48 As, with a thickness of 10 μm. The substrate dielectric layer is indium phosphide (InP), with a thickness of 10 μm. 0.52 Ga 0.48 As a photoelectric conversion layer, it has advantages such as wide bandgap adjustment range, high photoelectric conversion efficiency, fast carrier transport and high thermal stability.

[0032] As one embodiment, the structure of the one-dimensional photonic crystal microcavity is as follows: A and B are periodically arranged Si and SiO2, and their alternating arrangement forms two DBR mirrors. C is an air defect layer. The number of periods is given. The thicknesses of Si and SiO2 in the DBR mirror are d and d, respectively. A =λ c / 4n A and d B =λ c / 4n B , where λ c =1300nm is the center wavelength, and the refractive index n of silicon (Si) A The refractive index n of SiO2 varies with wavelength. B The value is 1.447. The length and width of the DBR mirror are both 10 μm. The period of the graphene ribbon-suspended top mirror is... Period of the bottom mirror closely attached to the photoelectric conversion layer

[0033] Choosing an appropriate periodic combination in the structure of a one-dimensional photonic crystal can increase the peak value of the transmission peak or the absorption peak of the photoelectric conversion layer and reduce its full width at half maximum (FWHM), thereby improving the spectral resolution of the micro-spectrometer. In this embodiment, the initial cavity length of the one-dimensional photonic crystal optical microcavity is 0.90 μm. A DC driving voltage is applied between the graphene and the transparent electrode via the circuit control module 9. When the voltage increases from 0V to 15V, the center wavelength of the absorption peak changes from 1.61 μm to 1.08 μm, with a wavelength adjustment range of 0.53 μm. Figure 2 As shown, Figure 2 The illustration shows the change in the cavity length of the microcavity with voltage.

[0034] By using a DC driving voltage to deform the graphene strip under the influence of an electric field, the top mirror can be moved to adjust the cavity length, resonant wavelength, and resonant absorption peak in the photoelectric conversion layer, thereby achieving selective absorption of the incident spectrum and obtaining the change of photocurrent with driving voltage. Static spectral analysis can then be achieved by using the correspondence between driving voltage and center wavelength.

[0035] More preferably, the circuit control module 9, which is connected to the graphene and the transparent electrode, outputs an alternating voltage with a frequency close to the natural vibration frequency of the top mirror.

[0036] In this technical solution, when the frequency of the AC driving voltage is close to the natural vibration frequency of the upper reflecting mirror, only a very small voltage is needed to drive the top mirror to vibrate under forced conditions, causing the cavity length of the microcavity to change periodically with time, and causing the resonant absorption peak in the photoelectric conversion layer to change periodically with time, thereby achieving selective absorption of the incident spectrum and obtaining the change of photocurrent with vibration time. The time-resolved dynamic spectral analysis is achieved by the correspondence between vibration time and center wavelength.

[0037] In this embodiment, due to the selective absorption of light of different wavelengths by the photoelectric conversion layer 3, the photocurrent varying with voltage is detected in the photoelectric conversion layer by the data acquisition and analysis system 10. Since the full width at half maximum (FWHM) and peak value of the absorption peak are not entirely the same, and the conversion efficiency of the photoelectric conversion layer for different wavelengths of light is inconsistent, the spectrum needs to be corrected to improve the accuracy of spectral reconstruction. The correction factor η(λ) varies with the center wavelength of the absorption peak. The correction factor depends only on the physical structure of the microcavity and the properties of the photoelectric conversion layer, and is independent of the incident spectrum; it can be calibrated in advance during the fabrication of the miniature spectrometer.

[0038] In this embodiment, since the absorption peak has a single-peak structure and the FWHM is extremely small, the spectral curve is reconstructed by coordinate transformation. By utilizing the correspondence between voltage and the center wavelength of the absorption peak, the change of photocurrent with voltage is converted into the change of photocurrent with wavelength, and the reconstructed spectral curve is obtained to realize static spectral analysis.

[0039] In this embodiment, when the top mirror is in the equilibrium position, an AC driving voltage is applied between the graphene and the transparent electrode via the circuit control module 9. When the AC driving voltage is 0.544V, the graphene strip is subjected to a periodic driving force F = F0cos(2πνt), where the maximum value of the driving force F0 is 0.06nF and the frequency ν of the driving force is 5.16kHz. The graphene strip undergoes forced vibration after being subjected to the periodic driving force. Taking the initial cavity length of the optical microcavity as 0.69μm, the time it takes for the top mirror to move from the lowest point to the highest point within one vibration cycle is considered half a cycle. The displacement changes with time, as shown below. Figure 3 As shown in the lower right inset, the displacement of the top mirror over time causes the cavity length of the microcavity to change over time, as... Figure 3 As shown in the upper left inset, changes in cavity length shift the absorption peak, causing the center wavelength of the absorption peak to change over time, as illustrated in the example. Figure 3 As shown.

[0040] In this embodiment, the photoelectric conversion layer selectively absorbs incident light of different wavelengths within half a cycle of each spectral detection, meaning the absorption peak changes with vibration time. The data acquisition and analysis system 10 detects the time-varying photocurrent in the photoelectric conversion layer. Utilizing the correspondence between the center wavelength of the absorption peak and the vibration time within half a cycle of the DBR mirror, a coordinate transformation method is used to reconstruct the spectral curve, converting the change in photocurrent over time into a change in photocurrent over wavelength to obtain the reconstructed spectrum. The time resolution of the miniature spectrometer is half the vibration period of the top mirror. Due to the high vibration frequency of the top mirror, the time response speed of the spectral analysis is on the order of 0.1 milliseconds.

[0041] In this embodiment, adjusting the geometric parameters of the micro-spectrometer, such as increasing the width of the graphene band, decreasing the width of the trench, or increasing the internal stress within the graphene, can significantly increase the resonant frequency and improve the time resolution of the micro-spectrometer. For example, when the graphene band width is 10 μm, the trench width is 4 μm, and the internal stress of the graphene is 250 MPa, the resonant frequency is 300 kHz, and the time resolution can reach 1.67 μs.

[0042] Another embodiment of the present invention, a miniature spectrometer, such as Figure 4 As shown, the system includes: a broadband light source 11, a microscope objective 12, a graphene microelectromechanical system-photonic crystal composite structure 13, a microscope 14, and a high-speed camera 15. The graphene microelectromechanical system-photonic crystal composite structure 13 is placed at the imaging plane of the microscope objective. The incident spectrum is converged using the microscope objective, and the high-speed camera is used to capture the image.

[0043] In this technical solution, the graphene microelectromechanical system-photonic crystal composite structure is a one-dimensional planar structure that does not affect the propagation angle and focusing characteristics of light. The light passing through the device is focused by the lens without changing the one-to-one correspondence between the object point and the image point. Combined with traditional imaging equipment such as microscopes and high-speed cameras, it can simultaneously achieve time-resolved and spatial-resolved spectral imaging.

[0044] The sample to be tested is placed between a broadband light source 11 and the objective lens 12 of a microscope. The light emitted by the broadband light source 11 is absorbed by the sample to generate different wavelength spectra. When the spectra to be tested are focused by the objective lens of the microscope 14, they are incident on the graphene microelectromechanical system-photonic crystal composite structure 13. This structure separates the incident spectrum over time and then images it on a high-speed camera 15.

[0045] In this embodiment, the graphene microelectromechanical system-photonic crystal composite structure is placed at the imaging plane of the microscope objective. In this case, a photoelectric conversion layer is not required, and the photonic crystal structure is taken as a symmetrical structure. To improve transmittance, number of cycles The DBR mirror has a length and width of 50 μm, and the graphene band width W is 4. g The groove width is 6μm and L. g The initial cavity length is 7 μm. When the top mirror is in the equilibrium position, an AC driving voltage is applied between the graphene and the transparent electrode via the circuit control module 9. When the AC driving voltage is 0.6065V, the maximum value F0 of the periodic driving force on the graphene strip is 0.075nF, the driving force frequency f is 4.98kHz, the vibration period T1 is 0.2008ms, and the initial cavity length of the photonic crystal optical microcavity is 6.5μm.

[0046] In this embodiment, the numerical aperture of the microscope objective is 0.4642, the lens radius is 5 mm, and the lens magnification is 10x. The maximum incident angle of the emitted light cone is 3°. When the light emitted from the object to be imaged is focused by the microscope objective and incident on the graphene microelectromechanical system-photonic crystal composite structure, the planar structure, which does not alter the optical converging imaging characteristics, separates the incident spectrum over time and images it on a high-speed camera. The photocurrent received by each pixel of the high-speed camera changes over time. Similarly, using coordinate transformation, the change in photocurrent of the corresponding pixel at each image point over time is converted into a change in photocurrent over wavelength to obtain a reconstructed spectrum, thus acquiring time-resolved spectral information. The top mirror can perform one spectral detection every half-cycle of vibration; the higher the vibration frequency, the higher the time resolution.

[0047] In this embodiment, the imaging time is obtained from the number of frames captured by the high-speed camera, the displacement of the top mirror vibration is obtained from the imaging time, and then the cavity length of the optical microcavity is obtained. Based on the correspondence between the cavity length and the center wavelength of the transmission peak, the spectral information of the luminescent material is finally obtained as a function of time and space, thus realizing time-resolved and space-resolved spectral imaging.

[0048] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A miniature spectrometer, characterized in that, The system includes a graphene microelectromechanical system-photonic crystal composite structure (13), a circuit control module (9), and a data acquisition and analysis system (10). The graphene microelectromechanical system-photonic crystal composite structure (13) includes a substrate dielectric layer (1), a transparent electrode (2), a pillar (5), a graphene strip (6), and a top mirror (7). The transparent electrode (2) and the pillar (5) are disposed on the substrate dielectric layer (1), and the top mirror (7) is suspended from the pillar (5) by a double-layer graphene strip (6). The transparent electrode (2) integrates a graphene microelectromechanical system-photonic crystal composite structure (13), a circuit control module (9), and a data acquisition and analysis system (10). A photoelectric conversion layer (3) is formed by growing a one-dimensional photonic crystal on the photoelectric conversion layer (3) to form a bottom mirror (4); a circuit control module (9) is connected to the transparent electrode (2) and the electrode (8) on the graphene strip (6) to apply a voltage between the bilayer graphene strip (6) and the transparent electrode (2); a data acquisition and analysis system (10) is connected to the electrodes at both ends of the photoelectric conversion layer (3) and the electrode (8) on the graphene strip (6) to monitor the changes in photocurrent in the photoelectric conversion layer (3) and the changes in resistance in the graphene strip (6).

2. A miniature spectrometer according to claim 1, characterized in that, The structure of a one-dimensional photonic crystal is A and B are periodically arranged silicon atoms. and silicon dioxide C represents the air defect layer. , The number of cycles.

3. A miniature spectrometer according to claim 2, characterized in that, The thickness of the periodically arranged Si and SiO2 is one-quarter of the center wavelength of the incident spectrum, and its length and width range are within... .

4. A miniature spectrometer according to claim 3, characterized in that, The top mirror (7) and the bottom mirror (4) are arranged alternately by A and B to form a distributed Bragg reflector, i.e., a DBR mirror.

5. A miniature spectrometer according to claim 1, characterized in that, The photoelectric conversion layer (3) is indium gallium arsenide. Its thickness is Within plus or minus 20%.

6. A miniature spectrometer according to claim 1, characterized in that, The output of the circuit control module (9) is an adjustable DC voltage.

7. A miniature spectrometer according to claim 1, characterized in that, The circuit control module (9) outputs an alternating voltage with a frequency close to the natural vibration frequency of the top mirror (7).

8. A miniature spectrometer according to claim 1, characterized in that, The substrate dielectric layer (1) is indium phosphide. .

9. A miniature spectrometer, characterized in that, The system includes a graphene microelectromechanical system-photonic crystal composite structure (13), a microscope (14), and a high-speed camera (15). The graphene microelectromechanical system-photonic crystal composite structure (13) includes a substrate dielectric layer (1), a transparent electrode (2), a pillar (5), a bilayer graphene strip (6), a top mirror (7), and an electrode (8). The graphene microelectromechanical system-photonic crystal composite structure (13) does not have a photoelectric conversion layer. The transparent electrode (2) and the pillar (5) are disposed on the substrate dielectric layer (1), and the top mirror (7) is suspended from the pillar (5) by the bilayer graphene strip (6). Above, a one-dimensional photonic crystal is grown on the substrate medium layer (1) to form the bottom mirror (4); the graphene microelectromechanical system-photonic crystal composite structure (13) is set at the imaging plane of the objective lens of the microscope (14); the sample to be tested is set between the broadband light source and the objective lens of the microscope (14). The light emitted by the broadband light source is absorbed by the sample to generate different wavelength spectra to be tested. When the spectra to be tested are focused by the objective lens of the microscope (14) and incident on the graphene microelectromechanical system-photonic crystal composite structure (13), the incident spectrum is separated by time and then photosensitive and imaged on the high-speed camera (15).

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