Dispersion coherent imaging spectrometer with one-dimensional ultra-wide field of view and ultra-high spectral resolution

Abstract

The invention discloses a one-dimensional ultra-wide field-of-view ultra-high spectral resolution dispersion coherent imaging spectrometer, which belongs to the technical field of spectral imaging, and comprises a first microlens array used for obtaining incident light of a one-dimensional ultra-wide field-of-view in a horizontal plane; the plurality of optical fibers are used for transmitting incident light of a one-dimensional ultra-wide field of view; the second micro lens array is used for collimating incident light from each optical fiber into broadband parallel light beams; the grating beam splitter interferometer is used for dispersing the broadband parallel light beams into a plurality of narrow-band parallel light beams with different propagation directions; the cylindrical lens is used for converging the two paths of coherent light of each narrow-band parallel light beam to a target block of the detector, and converging the narrow-band parallel light beams with different propagation directions to different target blocks respectively; and the detector is used for obtaining a continuous broadband ultra-high resolution spectrum according to the two paths of coherent light received by each target block. According to the invention, a one-dimensional ultra-wide field of view is obtained in a horizontal plane, and ultra-high spectral resolution can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of spectral imaging technology, specifically relating to a one-dimensional ultra-wide field of view ultra-high spectral resolution dispersive coherent imaging spectrometer. Background Technology

[0002] Field of view and spectral resolution are important indicators for evaluating the performance of imaging spectrometers. Achieving a two-dimensional ultra-wide field of view typically involves four methods: the first is using fisheye lenses, reflective panoramic lenses, or a combination of both; the second is using artificial compound eyes; the third is using concentric multi-scale cameras; and the fourth is using panoramic single-center fiber-coupled imagers. However, none of these methods can achieve high-resolution spectral measurements. Those skilled in the art should know that while some scanning imaging spectrometers can achieve a one-dimensional ultra-wide field of view through scanning, they cannot achieve ultra-high spectral resolution. In recent years, an ultra-wide-angle, high-resolution snapshot imaging spectrometer has emerged in the prior art. This spectrometer uses a microlens array to acquire a one-dimensional ultra-wide field of view and a static interferometer (using a fixed reflective grating instead of the moving plane mirror of a Michelson interferometer) to achieve ultra-high spectral resolution. However, the spectral range of this spectrometer is too narrow, and it cannot achieve ultra-high spectral resolution (picometer-level) spectral measurements across a wide wavelength range in the ultraviolet spectral band. Furthermore, existing spatial modulation interferometry, dispersive spectroscopy, and filter spectroscopy techniques all fail to achieve ultra-high spectral resolution spectral measurements across a wide wavelength range.

[0003] In the infrared spectrum, detector noise plays a dominant role. Although time-modulated interferometry based on Michelson or Fabry-Perot interferometers can achieve ultra-high spectral resolution in the infrared wide band, it can only achieve ultra-high spectral resolution in the narrow band of the ultraviolet-visible spectrum.

[0004] In the ultraviolet-visible spectral range, photon noise dominates, and its level is proportional to the square root of the incident power, meaning it is proportional to the square root of the photon count. The advantages of interferometric spectroscopy disappear, and its performance degrades. Target shot noise is uniformly distributed across the entire Fourier transform spectral baseline. While this doesn't reduce spectral resolution, it lowers the signal-to-noise ratio (SNR) of the Fourier transform spectrum. Furthermore, target scintillation noise is unevenly distributed across the entire Fourier transform spectral baseline, further reducing both spectral resolution and the SNR. Therefore, time-modulated interferometric spectroscopy based on Michelson-type or Fabry-Perot interferometers can only achieve narrow-band ultra-high spectral resolution within the ultraviolet-visible spectral range.

[0005] In addition, there is an imaging spectrometer based on a grating beamsplitter interferometer in the existing technology, which includes two microlens arrays, multiple optical fibers, a planar transmission grating, two concave mirrors, a movable corner mirror, a fixed plane mirror, and an area array detector. It can simultaneously achieve two-dimensional ultra-wide field of view and wide-band ultra-high spectral resolution in the infrared spectral band, but it cannot achieve wide-band ultra-high spectral resolution spectral measurement in the ultraviolet-visible spectral band.

[0006] Spectral coherent imaging spectroscopy combines time-modulated interferometry, dispersive spectroscopy, and imaging techniques. It overcomes the shortcomings of interferometry in the ultraviolet-visible spectral range, has the advantage of wide-band ultra-high spectral resolution, improves the signal-to-noise ratio, and reduces the dynamic range requirements of area array detectors. It can achieve wide-band ultra-high spectral resolution spectral measurements in the ultraviolet-visible spectral range, but it cannot achieve an ultra-wide field of view. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer. The technical problem to be solved by this invention is achieved through the following technical solution: This invention provides a one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer, comprising: The first microlens array includes multiple first microlenses arranged in an arc in the horizontal plane to obtain incident light with a one-dimensional ultra-wide field of view in the horizontal plane. The second microlens array includes a plurality of second microlenses arranged in a straight line in the first direction; Multiple optical fibers, each with its two ends coupled to a first microlens in the first microlens array and a second microlens in the second microlens array, respectively, to transmit the incident light of the one-dimensional ultra-wide field of view. The second microlens is used to collimate the incident light from each optical fiber into a wide-band parallel beam. A grating beam splitter interferometer is used to disperse a wide-band parallel beam into multiple narrow-band parallel beams with different propagation directions. Each narrow-band parallel beam includes two coherent beams with equal light intensity and the same propagation direction. The grating beam splitter interferometer includes a planar transmission grating, and the first direction is the extension direction of the grating groove in the planar transmission grating. A cylindrical lens and a detector, the detector comprising a pixel array divided into multiple blocks, the cylindrical lens being used to converge two coherent beams of each narrow-band parallel beam to a target block of the detector, and to converge narrow-band parallel beams with different propagation directions to different target blocks respectively; the detector being used to obtain a continuous wideband ultra-high resolution spectrum of a target unit obtained by a first microlens based on the two coherent beams received from each target block.

[0008] In one embodiment of the present invention, the spatial angular resolution of the imaging spectrometer is equal to the field of view of each first microlens. The number of the first microlens and the number of the second microlens are both , The field of view angle represents the one-dimensional ultra-wide field of view within the horizontal plane.

[0009] In one embodiment of the present invention, the grating beam splitter interferometer further includes: a concave reflector, a fixed plane mirror, and a movable corner reflector; wherein, The planar transmission grating is used to perform a first diffraction on the incident wide-band parallel beam to generate zero-order diffracted light and first-order diffracted light. The reflected zero-order diffracted light and first-order diffracted light are then subjected to a second diffraction. The resulting first-order diffracted light of the zero-order diffracted light and the zero-order diffracted light of the first-order diffracted light serve as two coherent lights with equal light intensity and the same propagation direction in each narrow-band parallel beam, ultimately obtaining multiple narrow-band parallel beams with different propagation directions. The concave mirror is used to reflect the first-order diffracted light back to the planar transmission grating along the original optical path; The movable corner mirror is used to reflect the zeroth-order diffracted light back to the planar transmission grating along the original optical path in conjunction with the fixed plane mirror during the movement process.

[0010] In one embodiment of the present invention, the concave mirror is located on the optical path of the first-order diffracted light, and the center of curvature of the concave mirror is located at the incident center of the parallel beam on the planar transmission grating.

[0011] In one embodiment of the present invention, the pixel array includes OK, Column pixels, each block contains 1 row The number of pixels in the column, where , This indicates the number of the first microlens and the second microlens. This indicates the aperture size of the second microlens. Indicates the pixel size of the detector. In the formula, , These represent the maximum and minimum wavelengths of the incident light, respectively. Indicates rounding up. This indicates the pixel size of the detector.

[0012] In one embodiment of the present invention, the detector is specifically used to generate an interferogram corresponding to each target block based on the two coherent beams of the narrow-band parallel beams received by each target block within one scanning cycle of the moving corner reflector. Furthermore, Fourier transform is performed on each interferogram to obtain each narrow-band ultra-high resolution spectrum. By combining all the narrow-band ultra-high resolution spectra, a continuous wide-band ultra-high resolution spectrum of a target unit obtained by a first microlens is obtained.

[0013] In one embodiment of the present invention, two coherent beams of each narrow band generated by the incident light of a target unit obtained by a first microlens are converged to the detector and then received by the target blocks located in the same column of the detector.

[0014] In one embodiment of the present invention, in the first microlens array, the aperture size of each first microlens is [missing information]. , This represents the field of view of each first microlens. This represents the radius of the arc.

[0015] In one embodiment of the present invention, the incident half-angle of the optical fiber satisfy: ; The emission half-angle of the optical fiber satisfy: ; ; In the formula, This indicates the aperture size of the first microlens. This indicates the focal length of the first microlens. This indicates the focal length of the second microlens. The numerical aperture of an optical fiber. It represents the refractive index of the medium. In one embodiment of the present invention, the spectral resolution of the imaging spectrometer Represented as:

[0016] In the formula, Indicates the maximum optical path difference. This represents the maximum displacement of the moving corner mirror relative to the position with zero optical path difference. .

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the imaging spectrometer provided by the present invention, the multiple first microlenses of the first microlens array are arranged in an arc in the horizontal plane, which can obtain a one-dimensional ultra-wide field of view in the horizontal plane.

[0018] (2) The grating beam splitter interferometer in this invention includes a planar transmission grating. As a beam splitter, the planar transmission grating can generate two coherent beams. At the same time, as a dispersive element, the planar transmission grating can disperse a wide-band parallel beam into multiple narrow-band parallel beams. The spectral resolution of the imaging spectrometer provided by this invention is related to the maximum displacement of the moving corner mirror, but not to the spectral resolution of the planar transmission grating, thus achieving higher spectral resolution.

[0019] (3) In this invention, a moving corner mirror is used as a moving component in the grating beam splitter interferometer, which greatly reduces the modulation error and phase error of the sampling interferogram caused by the tilt of the moving mirror during the scanning process, and effectively eliminates the influence of the tilt of the moving mirror on the sampling interferogram during the scanning process. Therefore, the imaging spectrometer provided by this invention is insensitive to the tilt of the moving mirror during the scanning process.

[0020] (4) The imaging spectrometer provided by the present invention uses a combination of a grating beam splitter interferometer and a cylindrical lens, which makes full use of the performance of the planar transmission grating, making it both a beam splitter of the interferometer and a dispersive element of the imaging spectrometer, which is beneficial to saving costs.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is the equivalent optical path diagram in the horizontal plane of the one-dimensional ultra-wide field of view ultra-high spectral resolution dispersive coherent imaging spectrometer provided in this embodiment of the invention; Figure 2 This is the equivalent optical path diagram in the vertical plane of the one-dimensional ultra-wide field of view ultra-high spectral resolution dispersive coherent imaging spectrometer provided in this embodiment of the invention; Figure 3 This is a schematic diagram of the grating beam splitter interferometer provided in an embodiment of the present invention; Figure 4 This is the equivalent dispersion optical path diagram of the planar transmission grating provided in the embodiments of the present invention; Figure 5 These are the 1st, 127th, and 191st interferograms obtained using a field-of-view unit of a one-dimensional ultrawide field-of-view ultra-high spectral resolution dispersive coherent imaging spectrometer. Figure 6 yes Figure 5 The first interferogram and its restored spectrum, and the input spectrum are shown below; Figure 7 yes Figure 5The 127th interferogram shown here, along with its restored spectrum and the input spectrum; Figure 8 yes Figure 5 The 191st interferogram shown here, along with its restored spectrum and input spectrum, are displayed. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0024] Figure 1 This is the equivalent optical path diagram in the horizontal plane of the one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer provided in this embodiment of the invention. Figure 2 This is the equivalent optical path diagram in the vertical plane of the one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer provided in this embodiment of the invention. For example... Figures 1-2 As shown, this embodiment of the invention provides a one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer, comprising: The first microlens array 1 includes a plurality of first microlenses 101 arranged in an arc in the horizontal plane to obtain incident light with a one-dimensional ultra-wide field of view in the horizontal plane. The second microlens array 2 includes a plurality of second microlenses 201 arranged in a straight line in the first direction; Multiple optical fibers 3, each optical fiber 3 having a first microlens 101 in the first microlens array 1 and a second microlens 201 in the second microlens array 2 coupled at both ends to transmit incident light with a one-dimensional ultra-wide field of view. The second microlens 201 is used to collimate the incident light from each optical fiber 3 into a wide-band parallel beam. The grating beam splitter interferometer 4 is used to disperse a wide-band parallel beam into multiple narrow-band parallel beams with different propagation directions. Each narrow-band parallel beam includes two coherent beams with equal light intensity and the same propagation direction. The grating beam splitter interferometer 4 includes a planar transmission grating 401, with the first direction being the extension direction of the grating groove in the planar transmission grating 401. Cylindrical lens 5 and detector 6, detector 6 includes a pixel array divided into multiple blocks, cylindrical lens 5 is used to converge two coherent beams of each narrow band parallel beam to a target block of detector 6, and to converge narrow band parallel beams with different propagation directions to different target blocks respectively; detector 6 is used to obtain a continuous wideband ultra-high resolution spectrum of a target unit obtained by a first microlens 101 based on the two coherent beams received by each target block.

[0025] In this embodiment, the first and second microlens arrays each include a plurality of first microlenses 101 and a plurality of second microlenses 201. The plurality of first microlenses 101 are arranged in an arc shape in a horizontal plane, while the plurality of second microlenses 201 are arranged in a straight line along a first direction in the horizontal plane. Each first microlens 101 is used to acquire the incident light of a target unit. Therefore, the first microlens array 1 can obtain a one-dimensional ultra-wide field of view, such as 120°, of incident light in the horizontal plane. The radius of the aforementioned arc shape is denoted as . The field of view of each first microlens 101 is denoted as . The spatial angular resolution of the imaging spectrometer Equal to the field of view of each first microlens 101 , .

[0026] The incident light from a target unit acquired by each first microlens 101 is transmitted to a second microlens 201 via an optical fiber 3. The second microlens 201 collimates the incident light from each optical fiber 3 into a broadband parallel beam. It can be seen that the number of first microlenses 101 in the first microlens array 1 is the same as the number of second microlenses 201 in the second microlens array 2. , This represents the field of view angle of a one-dimensional ultra-wide field of view in the horizontal plane, and the aperture size of each first microlens 101 is [missing information]. .

[0027] In this embodiment, the incident half-angle of optical fiber 3 satisfy: ; The output half-angle of fiber 3 satisfy: ; ; In the formula, This indicates the aperture size of the first microlens 101. This indicates the focal length of the first microlens 101. This indicates the focal length of the second microlens 201. This indicates the numerical aperture of fiber 3. It represents the refractive index of the medium. Furthermore, the wideband parallel beam enters the grating beam splitter interferometer 4, which disperses the wideband parallel beam into multiple narrowband parallel beams. Each narrowband parallel beam has a different propagation direction, but the two coherent light paths contained in each narrowband parallel beam have the same propagation direction and intensity. It should be noted that in this embodiment, "wideband" is relative to the parallel beam obtained after dispersion, indicating that the wideband parallel beam is separated into parallel beams with a smaller spectral range. Conversely, "narrowband" is also relative to the input wideband parallel beam. There is no absolute numerical boundary between "wideband" and "narrowband," which mainly depends on the design goals of the imaging spectrometer. Of course, "wideband" can cover the operating spectral range of the imaging spectrometer, such as 250-400 nm or 300-500 nm.

[0028] In this embodiment, detector 6 is located at Figure 2 shown In the plane, where, x The axis is parallel to the extending direction of the grating grooves in the planar transmission grating 401, and each row of pixels in the detector 6 is parallel to... The axis, each column of pixels is parallel to The pixel array is divided into multiple non-overlapping blocks of the same size. For example, the number of pixels in each column of detector 6 is denoted as... The number of pixels in each row is denoted as ,in, , , Let represent the theoretical maximum wavelength and theoretical minimum wavelength of the incident light, respectively. Indicates rounding up. , Indicates the pixel size in detector 6. This indicates the aperture size of the second microlens 201. This indicates the number of the first microlens 101 and the second microlens 201, with each block containing one row. The pixels in the column, the entire pixel array is divided into Each block.

[0029] Cylindrical lens 5 along the The axially converging beam can converge the two coherent beams of each narrow-band parallel beam to a target block of detector 6 (for generating a narrow-band interferogram). Because the propagation directions of different narrow-band parallel beams are different, the two coherent beams of different narrow-band parallel beams are converged to different target blocks in the same column of detector 6. Therefore, detector 6 can obtain a continuous wideband ultra-high resolution spectrum of a target unit obtained by a first microlens 101 based on the two coherent beams of the narrow-band parallel beams received by each target block in that column. Secondly, the cylindrical lens 5... The beam will neither converge nor diverge in the axial direction (i.e., in the direction of the axis). (The axial direction is equivalent to a parallel plate), therefore in In the axial direction, the incident light from different target units obtained by different first microlenses 101 will not be converged to the same column of target blocks in the detector 6, so that the incident light obtained by each first microlens 101 does not interfere with each other. Furthermore, the cylindrical lens 5 in The axial direction neither focuses nor diverges the beam, allowing each first microlens 101 to acquire incident light with sufficient energy.

[0030] Figure 3 This is a schematic diagram of the grating beam splitter interferometer 4 provided in an embodiment of the present invention. Figure 2-3 As shown, the grating beam splitter interferometer 4 also includes: a concave mirror 402, a fixed plane mirror 403, and a movable corner mirror 404; wherein, The planar transmission grating 401 is used to perform the first diffraction on the incident wide-band parallel beam to generate zero-order diffracted light and first-order diffracted light. The zero-order diffracted light and first-order diffracted light reflected back are then subjected to a second diffraction. The first-order diffracted light of the zero-order diffracted light and the zero-order diffracted light of the first-order diffracted light are used as two coherent lights with equal light intensity and the same propagation direction in each narrow-band parallel beam. Finally, multiple narrow-band parallel beams with different propagation directions are obtained. The concave mirror 402 is used to reflect the first-order diffracted light back to the plane transmission grating 401 along the original optical path. The movable corner mirror 404 is used to reflect the zero-order diffracted light back to the plane transmission grating 401 along the original optical path in conjunction with the fixed plane mirror 403 during the movement process.

[0031] In this embodiment, the concave mirror 402 is located on the optical path of the first-order diffracted light, and the center of curvature of the concave mirror 402 is located at the incident center of the parallel beam on the plane transmission grating 401. This ensures that the optical paths of the first-order diffracted light of different wavelengths generated by the first diffraction are the same and are reflected back to the plane transmission grating 401 along the original optical path. In addition, the optical path difference between the two coherent lights generated by the grating beam splitter interferometer 4 can be four times the displacement of the moving angle mirror 404 from the zero optical path difference position.

[0032] The grating equation of the planar transmission grating 401 can be expressed as: ; In the formula, Indicates the diffraction order. This represents the wavelength of the incident parallel light beam. Represents the grating constant. This indicates the angle between the parallel beam and the grating normal. This indicates the wavelength of the parallel beam after diffraction by the grating. of Order of diffraction angle.

[0033] The one-dimensional ultra-wide field of view, ultra-high spectral resolution dispersive coherent imaging spectrometer provided by this invention... Considering Fraunhofer diffraction, when a parallel beam is incident perpendicularly onto the planar transmission grating 401, the transmission efficiency is: ; Here, and These represent the real and imaginary parts of the refractive index of the grating material, respectively. This indicates the width of the light-transmitting slit on the planar transmission grating 401. Angular wave number ( ), Let represent the intensity of the parallel beam. Considering that the two beams from the grating beam splitter interferometer 4 pass through the planar transmission grating 401 twice, the intensity of the two beams from the grating beam splitter interferometer 4 is... and It can be represented as: ; ; because This indicates that the energy of the incident light is uniformly distributed between the two beams of the grating beamsplitter interferometer 4, demonstrating that the planar transmission grating 401, as a beamsplitter, has superior performance compared to traditional interferometer beamsplitters.

[0034] Furthermore, the detector 6 is specifically used to generate an interferogram corresponding to each target block based on the two coherent beams of the narrow-band parallel beams received by each target block during one scanning cycle of the moving corner reflector 404. The detector 6 further performs a Fourier transform on each interferogram to obtain the ultra-high resolution spectrum of each narrow-band. By combining all the ultra-high resolution spectra of the narrow-band, the detector 6 obtains the continuous wide-band ultra-high resolution spectrum of a target unit obtained by a first microlens 101.

[0035] It should be understood that after the two coherent beams of each narrow band generated by the incident light of a target unit obtained by a first microlens 101 are converged to the detector 6, they are received by the target blocks located in the same column in the detector 6. Each target block in the column records a separate narrow band spectrum. By combining the various narrow band spectra recorded by all the target blocks in the column, a continuous wideband ultra-high resolution spectrum of a target unit obtained by a first microlens 101 is obtained.

[0036] Figure 4 This is the equivalent dispersion light path diagram of the planar transmission grating 401 provided in the embodiment of the present invention. Figure 4 In the diagram, each ray represents the central ray of a broadband parallel beam. The red dashed line represents the ray passing through the principal point on the image side of the cylindrical lens and parallel to the wavelength. Broadband parallel beams of light are straight lines that are parallel to each other. Indicates wavelength as A wide-band parallel beam, The wavelength represents the center wavelength of the broad-band incident spectrum. A wide-band parallel beam, This indicates the focal length of cylindrical lens 5. Indicates wavelength as A wideband parallel beam with a wavelength of The angle between the first-order diffracted beams obtained by the first diffraction of a broadband parallel beam through a plane transmission grating 401. The wavelength is... The central ray of the first-order diffracted beam obtained by the first diffraction of a broadband parallel beam through the planar transmission grating 401 coincides with the optical axis of the cylindrical lens 5, with a wavelength of The propagation direction of the coherent light generated by the wideband parallel beam passing through the grating beam splitter interferometer 4 is perpendicular to the plane of the detector 6. The wavelength is represented by the center wavelength. The wideband parallel beam finally hits the detector's 6-plane. Coordinates along the axis, Indicates wavelength as The wideband parallel beam finally hits the detector's 6-plane. Coordinates along the axis. (Regarding the center wavelength) ,make Therefore, ; In the formula, It can be represented as: .

[0037] Assumption Indicates wavelength as A wideband parallel beam with a wavelength of The angle between the first-order diffracted beams obtained by the first diffraction of a broadband parallel beam through a plane transmission grating 401 and the diffracted beams. Indicates wavelength as A wideband parallel beam with a wavelength of The angle between the first-order diffracted beams obtained by the first diffraction of a broadband parallel beam through the plane transmission grating 401 can be obtained. ; .

[0038] Assumption This indicates the wavelength as the maximum wavelength. The wideband parallel beam finally hits the detector's 6-plane. Coordinates along the axis, Indicates the wavelength as the minimum wavelength The wideband parallel beam finally hits the detector's 6-plane. From the coordinates along the axis, we can obtain: ; .

[0039] After one scanning cycle of the moving corner reflector 404, the detector 6 generates an interferogram based on the two coherent beams of each narrow-band parallel beam received from different target blocks. Each interferogram can be represented as: ; In the formula, This represents the displacement of the moving corner mirror 404 to the position of zero optical path difference. Indicates wave number, Indicates wave number The input spectral intensity.

[0040] According to the Nyquist theorem, to completely reconstruct the original signal, the required sampling frequency is at least twice the highest frequency of the original signal. Let... The sampling interval (the reciprocal of the sampling frequency) can be expressed as: ; In the formula, This indicates the maximum wavenumber of the incident light.

[0041] The theoretical spectral resolution of the imaging spectrometer provided by this invention It can be represented as: ; In the formula, Indicates optical path difference, Indicates the maximum optical path difference. This indicates the maximum displacement of the moving angle mirror 404 relative to the zero optical path difference position. .

[0042] Considering the impact of the apodization effect on spectral resolution, the actual working spectral resolution It can be represented as: .

[0043] set up The number of sampling points for each interferogram can be obtained by dividing the maximum optical path difference by the sampling interval. Therefore, the minimum number of sampling points for each interferogram... Represented as: .

[0044] The following simulation experiment further illustrates the one-dimensional ultra-wide field of view ultra-high spectral resolution dispersive coherent imaging spectrometer provided by this invention.

[0045] Specifically, the relevant parameters are as follows: the field of view angle of the one-dimensional ultrawide field of view of the first microlens array is... The field of view of each first microlens in the first microlens array is The number of first microlenses in the first microlens array is The radius of the arc formed by the first microlens array is The aperture size of each first microlens is The number of second microlenses in the second microlens array is The aperture size of each second microlens is The grating constant of the planar transmission grating is The focal length of the cylindrical lens is The detector's pixel size is Each row of the detector (parallel to) The number of pixels on each axis is 600, and the number of pixels in each column of the detector is... The incident light has a spectral range of 250 nm to 400 nm, expressed in wavenumber as 40,000 cm⁻¹. -1 Up to 25000cm -1 The theoretical spectral resolution (expressed in wavenumber) is 0.05 cm⁻¹. -1 The working spectral resolution (expressed in wavenumber) is 0.1 cm⁻¹. -1 .

[0046] Figure 5 These are the 1st, 127th, and 191st interferograms obtained using a field-of-view unit of a one-dimensional ultra-wide field-of-view ultra-high spectral resolution dispersive coherent imaging spectrometer. For example... Figure 5As shown, the center wavelength of the first interferogram is 250 nm, the center wavelength of the 127th interferogram is 320 nm, and the center wavelength of the 191st interferogram is 400 nm.

[0047] Figure 6 yes Figure 5 The first interferogram shown includes its restored spectrum and the input spectrum (a narrow band with a center wavelength of 250 nm). In the restored spectrum, the blue solid line represents the restored spectrum when the moving corner mirror has no angular error, and the red dashed line represents the restored spectrum when the moving corner mirror has a small angular error. The centers of the five peaks in the restored spectrum and the input spectrum are located at 249.99875 nm, 249.999375 nm, 250 nm, 250.000625 nm, and 250.00125 nm, respectively. It is easy to see that the spectral resolution for the narrow band with a center wavelength of 250 nm is approximately 0.625 pm.

[0048] Figure 7 yes Figure 5 The 127th interferogram shown includes its restored spectrum and the input spectrum (a narrow band with a center wavelength of 320 nm). In the restored spectrum, the solid blue line represents the restored spectrum when the moving corner mirror has no angular error, and the dashed red line represents the restored spectrum when the moving corner mirror has a small angular error. The centers of the five peaks in both the restored and input spectra are located at 319.997972 nm, 319.998976 nm, 320 nm, 320.001024 nm, and 320.002048 nm, respectively. It is easy to see that the spectral resolution for the narrow band with a center wavelength of 320 nm is approximately 1.024 pm.

[0049] Figure 8 yes Figure 5 The 191st interferogram shown includes its restored spectrum and the input spectrum (a narrow band with a center wavelength of 400 nm). In the restored spectrum, the solid blue line represents the restored spectrum when the moving corner mirror has no angular error, and the dashed red line represents the restored spectrum when the moving corner mirror has a small angular error. The centers of the five peaks in both the restored and input spectra are located at 399.9968 nm, 399.9984 nm, 400 nm, 400.0016 nm, and 400.0032 nm, respectively. It is easy to see that the spectral resolution for the narrow band with a center wavelength of 400 nm is approximately 1.6 pm.

[0050] As can be seen from the simulation results above, the one-dimensional ultra-wide field of view ultra-high spectral resolution dispersive coherent imaging spectrometer provided by the present invention can simultaneously obtain a one-dimensional ultra-wide field of view with a field angle of 120º horizontal plane and a wide-band ultra-high spectral resolution of approximately 0.625 picometers to 1.6 picometers for the wavelength range of 250 nm to 400 nm.

[0051] As can be seen from the above embodiments, the beneficial effects of the present invention are as follows: (1) In the imaging spectrometer provided by the present invention, the multiple first microlenses of the first microlens array are arranged in an arc in the horizontal plane, which can obtain a one-dimensional ultra-wide field of view in the horizontal plane.

[0052] (2) The grating beam splitter interferometer in this invention includes a planar transmission grating. As a beam splitter, the planar transmission grating can generate two coherent beams. At the same time, as a dispersive element, the planar transmission grating can disperse a wide-band parallel beam into multiple narrow-band parallel beams. The spectral resolution of the imaging spectrometer provided by this invention is related to the maximum displacement of the moving corner mirror, but not to the spectral resolution of the planar transmission grating, thus achieving higher spectral resolution.

[0053] (3) In this invention, a moving corner mirror is used as a moving component in the grating beam splitter interferometer, which greatly reduces the modulation error and phase error of the sampling interferogram caused by the tilt of the moving mirror during the scanning process, and effectively eliminates the influence of the tilt of the moving mirror on the sampling interferogram during the scanning process. Therefore, the imaging spectrometer provided by this invention is insensitive to the tilt of the moving mirror during the scanning process.

[0054] (4) The imaging spectrometer provided by the present invention uses a combination of a grating beam splitter interferometer and a cylindrical lens, which makes full use of the performance of the planar transmission grating, making it both a beam splitter of the interferometer and a dispersive element of the imaging spectrometer, which is beneficial to saving costs.

[0055] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0056] The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0057] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer, characterized in that, include: The first microlens array includes multiple first microlenses arranged in an arc in the horizontal plane to obtain incident light with a one-dimensional ultra-wide field of view in the horizontal plane. The second microlens array includes a plurality of second microlenses arranged in a straight line in the first direction; Multiple optical fibers, each with its two ends coupled to a first microlens in the first microlens array and a second microlens in the second microlens array, respectively, to transmit the incident light of the one-dimensional ultra-wide field of view. The second microlens is used to collimate the incident light from each optical fiber into a wide-band parallel beam. A grating beam splitter interferometer is used to disperse a wide-band parallel beam into multiple narrow-band parallel beams with different propagation directions. Each narrow-band parallel beam includes two coherent beams with equal light intensity and the same propagation direction. The grating beam splitter interferometer includes a planar transmission grating, and the first direction is the extension direction of the grating groove in the planar transmission grating. A cylindrical lens and a detector, the detector comprising a pixel array divided into multiple blocks, the cylindrical lens being used to converge two coherent beams of each narrow-band parallel beam to a target block of the detector, and to converge narrow-band parallel beams with different propagation directions to different target blocks respectively; the detector being used to obtain a continuous wideband ultra-high resolution spectrum of a target unit obtained by a first microlens based on the two coherent beams received from each target block.

2. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 1, characterized in that, The spatial angular resolution of the imaging spectrometer is equal to the field of view of each first microlens. The number of the first microlens and the number of the second microlens are both , The field of view angle represents the one-dimensional ultra-wide field of view within the horizontal plane.

3. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 1, characterized in that, The grating beam splitter interferometer further includes: a concave mirror, a fixed plane mirror, and a movable corner mirror; wherein... The planar transmission grating is used to perform a first diffraction on the incident wide-band parallel beam to generate zero-order diffracted light and first-order diffracted light. The reflected zero-order diffracted light and first-order diffracted light are then subjected to a second diffraction. The resulting first-order diffracted light of the zero-order diffracted light and the zero-order diffracted light of the first-order diffracted light serve as two coherent lights with equal light intensity and the same propagation direction in each narrow-band parallel beam, ultimately obtaining multiple narrow-band parallel beams with different propagation directions. The concave mirror is used to reflect the first-order diffracted light back to the planar transmission grating along the original optical path; The movable corner mirror is used to reflect the zeroth-order diffracted light back to the planar transmission grating along the original optical path in conjunction with the fixed plane mirror during the movement process.

4. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 3, characterized in that, The concave mirror is located on the optical path of the first-order diffracted light, and the center of curvature of the concave mirror is located at the incident center of the parallel beam on the planar transmission grating.

5. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 1, characterized in that, The pixel array includes OK, Column pixels, each block contains 1 row The number of pixels in the column, where , This indicates the number of the first microlens and the second microlens. This indicates the aperture size of the second microlens. Indicates the pixel size of the detector. In the formula, , Let represent the theoretical maximum wavelength and theoretical minimum wavelength of the incident light, respectively. Indicates rounding up. This indicates the pixel size of the detector.

6. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 5, characterized in that, Specifically, the detector is used to generate an interferogram corresponding to each target block based on the two coherent beams of the narrow-band parallel beams received by each target block within one scanning cycle of the moving corner reflector. Furthermore, a Fourier transform is performed on each interferogram to obtain the ultra-high resolution spectrum of each narrow-band. By combining all the ultra-high resolution spectra of the narrow-band, a continuous wide-band ultra-high resolution spectrum of a target unit obtained by a first microlens is obtained.

7. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 6, characterized in that, Two coherent beams of narrow bands generated by the incident light of a target unit obtained by a first microlens are converged to the detector and then received by the target blocks located in the same column of the detector.

8. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 7, characterized in that, In the first microlens array, the aperture size of each first microlens is [missing information]. , This represents the field of view of each first microlens. This represents the radius of the arc.

9. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 8, characterized in that, The incident half-angle of the optical fiber satisfy: ； The emission half-angle of the optical fiber satisfy: ； ； In the formula, This indicates the aperture size of the first microlens. This indicates the focal length of the first microlens. This indicates the focal length of the second microlens. The numerical aperture of an optical fiber. It represents the refractive index of the medium.

10. The one-dimensional ultra-wide field-of-view, ultra-high spectral resolution dispersive coherent imaging spectrometer according to claim 3, characterized in that, The spectral resolution of the imaging spectrometer Represented as: In the formula, Indicates the maximum optical path difference. This represents the maximum displacement of the moving corner mirror relative to the position with zero optical path difference. .

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