A Fourier spectrometer device for optimizing laser sampling wavelength

Abstract

This invention discloses a Fourier spectrometer device for optimizing laser sampling wavelengths. The device comprises an ultrastable laser, a small-field-of-view observation telescope, an interferometer module, a laser detector, a detector module, and a control, acquisition, and processing computer, all arranged in sequence according to the optical path. The device incorporates multiple technologies, including precise motor control, ultrastable laser self-alignment, high-sensitivity, high-precision laser signal sampling, and parallel plane mirror design for the interferometer arm plane reflectors. This device enables multiple foldbacks in the laser interferometer optical path to achieve a greater number of sampling optical paths, thereby increasing the laser's selectable wavelength range, thereby improving the signal-to-noise ratio and optimizing the laser sampling wavelength.

Description

Technical Field

[0001] The Fourier spectrometer device involved in the present invention is a long-distance, high-precision Fourier spectrometer device with 2N times the optical path sampling. This invention is based on the Nyquist sampling theorem, equal-inclination interferometry technology, and self-alignment technology. The core interference module adopts a common optical path design for the laser interferometer and the target signal interferometer. Through the aperture design of the beam splitter, the parallel plate design of the plane reflector of the laser interferometer arm, and the loop design of the beam splitter and the interferometer arm, N times of return are introduced into the laser interference optical path to obtain 2N times the sampling optical path, thereby increasing the optional wavelength range of the laser. The 2N times optical path sampling laser interferometer provides sampling pulses for the target interferometer, obtains redundant discrete intensity values of the target, and obtains the target's spectral information through Fourier transform, thereby improving the signal-to-noise ratio of signal inversion. The invention is suitable for the field of Fourier spectrometers. Background Art

[0002] Fourier spectroscopy technology has the advantages of multi-channel, high throughput and high resolution, and is widely used in materials, life, pharmacy and other fields.

[0003] A Fourier spectrometer consists of two interferometers: a laser interferometer and a target signal interferometer. The laser interferometer provides sampling pulses with equal optical path length differences. These sampling pulses stimulate the target interferometer to sample, obtaining a series of intensity information about the target signal. By performing a Fourier transform on this intensity information, its spectral information is obtained.

[0004] The Fourier spectrometer uses a design in which the laser interferometer and the target interferometer share the same optical path, i.e. the laser interferometer and the target interferometer have equal optical path lengths. The laser frequency selection of the laser interferometer must satisfy the Nyquist sampling theorem, i.e. the wavelength of the sampling laser of a Fourier spectrometer with an instrument spectral range of (λ1, λ2) must be less than half of the shortest wavelength in the instrument spectral range, i.e. it must be less than or equal to For infrared Fourier spectrometers operating at wavelengths greater than 1.5 μm, the laser wavelength that satisfies the Nyquist sampling theorem must be less than 0.75 μm, and stable helium-neon lasers (632.8 nm) are often used. However, as the operating band of Fourier spectrometers extends into the visible region, the wavelength of the sampling laser extends into the ultraviolet region, which makes laser selection more difficult.

[0005] There are two existing solutions to the sampling difficulties of visible Fourier spectrometer laser interferometers. The first is to use a stepper motor to achieve Nyquist sampling through the equally spaced movement of the stepper motor. The core component of this solution is the cross-roller bearing, which wears out with movement, affecting the life of the instrument and measurement accuracy. Secondly, the random deviation of the stepper motor's step length repeatability leads to non-equal optical path sampling, which will cause distortion of the inversion interferogram. The second is to multiply the clock sequence generated by the original laser by n to achieve Nyquist sampling. This solution increases the complexity of the electronics and adds delays in the circuit, causing the target sampling to lag and causing distortion of the inversion interferogram.

[0006] The shortcomings of the above-mentioned existing technologies are mainly reflected in the following two aspects: First, Nyquist sampling based on the equal-interval movement of the stepper motor is limited by the repeatability deviation of the step length, which will cause distortion of the inversion interferogram. At the same time, the inevitable friction loss of the cross-roller bearing of the stepper motor affects the life of the instrument and the measurement accuracy; Second, Nyquist sampling based on the n-fold frequency of the laser interferometer clock sequence is subject to the circuit delay, noise, etc. caused by the sampling itself, which causes distortion of the inversion interferogram. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a Fourier spectrometer device with n-times optical path sampling, which is suitable for the fields of Fourier spectrometer development, spectral analysis, etc.

[0008] The technical solutions of the present invention are as follows:

[0009] A long-distance, high-precision 2N-times optical path sampling Fourier spectrometer device, comprising an ultra-stable laser 1, a small-field observation telescope 2, an interference module 3, a laser detector 4, a detector module 5, and a control acquisition and processing computer 6 arranged in sequence according to optical path transmission; the small-field observation telescope 2 is composed of a plane reflector 7, a concave reflector 8, an electrically controlled adjustable aperture 9, and an off-axis parabolic reflector 10, and the two are coaxial; the interference module 3 is composed of a beam splitter 11, a fixed reflector 13, a linear motor 16, and a reflector 12 fixed to the linear motor, as shown in the attached manual. Figure 1 shown.

[0010] The small-field observation telescope 2 is composed of a plane reflector 7, a concave reflector 8, an electrically controlled adjustable diaphragm 9, and an off-axis parabolic reflector 10 and is coaxial; the plane reflector 7 is located in front of the concave reflector 8, and the electrically controlled adjustable diaphragm 9 is located at the focus of the concave reflector 8 and also at the focus of the off-axis parabolic reflector 10; the opening size of the electrically controlled adjustable diaphragm 9 is intelligently controlled by the control acquisition processing computer 6 according to the spectral resolution of the system, and the opening diameter φ of the electrically controlled adjustable diaphragm 9 is proportional to the spectral resolution ν of the system and the maximum wave number σ of the working band. max, and the constraint relationship between the focal length f′ of the off-axis parabolic reflector 10 satisfies:

[0011]

[0012] The 2N-fold sampling Fourier spectrometer device adopts single-side sampling, and its maximum spectral resolution is ν max , and the maximum stroke L of the linear motor max The relationship between the angle β between the beam splitter 11 and the incident light of the laser 1 satisfies the formula (2), where ν max The maximum spectral resolution of the Fourier spectrometer device with 2N times sampling, L max is the maximum stroke of the linear motor, β is the angle between the beam splitter 11 and the incident light of the laser 1, as shown in the appendix of the manual. Figure 2 shown.

[0013]

[0014] The reflector 12 is identical to the fixed reflector 13, and the positions of the reflector 12 and the fixed reflector 13 at zero position are symmetrical about the upper surface of the beam splitter 11; the fixed reflector 13 includes a plane reflector 14 and a small plane reflector 15, and the small plane reflector 15 and the ends of the plane reflector 14 form a parallel plate internal reflector, as shown in the appendix of the specification. Figure 2 As shown; the constraint relationship between the length l of the small plane reflector 15 and the number of times N that the laser is refracted between the parallel plates, the spacing d between the parallel plates, and the angle α between the incident light of the laser 1 and the plane reflector 14 satisfies the formula (3), where N is the number of times the laser is refracted between the parallel plates, l is the length of the small plane reflector 15, d is the spacing between the parallel plates, and α is the angle between the incident light of the laser 1 and the plane reflector 14, as shown in the appendix of the manual. Figure 2 shown.

[0015]

[0016] The detector module 5 can use different detectors according to the different working bands. If the working band of the instrument is 2-15μm, the detector module 5 has the ability to detect shortwave, medium wave and long wave, as shown in the attached manual. Figure 3 As shown, the detector module 5 includes an off-axis parabolic reflector 19, a short-wave color separation plate 20, a medium-wave color separation plate 21, a short-wave detector 22, a medium-wave detector 23, and a long-wave detector 24, which are placed in sequence according to the optical path transmission.

[0017] The beam splitter 11 comprises four different functional surface areas, as shown in the attached manual. Figure 4 As shown, the semi-transmissive surface 25, the anti-reflection surface 26, the anti-reflection surface 27, the reflecting surface 28; the diameter D of the beam splitter 11 and the initial position X of the reflector 12, the maximum stroke L of the linear motormax The constraint relationship between the length a of the plane reflector 14, the angle β between the beam splitter 12 and the incident light of the laser 1, and the angle α between the incident light of the laser 1 and the plane reflector 14 satisfies the formula (4); the constraint relationship between the length b of the semi-reflective surface 25 and the initial position X of the reflector 12, and the angle β between the beam splitter 11 and the incident light of the laser 1 satisfies the formula (5), where D is the diameter of the beam splitter 11, X is the initial position of the reflector 12, and L max is the maximum stroke of the linear motor, a is the length of the plane mirror 14, β is the angle between the beam splitter 11 and the incident light of the laser 1, α is the angle between the incident light of the laser 1 and the plane mirror 14, and b is the length of the semi-reflective and semi-transparent surface 25.

[0018] D≥(X+L max )sinβ+asinα(4)

[0019] b=X sinβ(5)

[0020] The working principle of the present invention is as follows:

[0021] The working process of the instrument is as follows, as shown in the attached manual. Figure 5 As shown, the first step is to turn on the instrument's control, acquisition, and processing computer 6. The second step is to select the desired operating band, resolution, and sampling mode. The third step is to perform a self-test. If an error message is displayed during the self-test, follow the prompts and restart the control, acquisition, and processing computer 6. If the self-test passes, proceed to the next step. The fourth step is to collect background data. The fifth step is to perform a spectral measurement of the target. The sixth step is to shut down the instrument after the measurement is complete.

[0022] The principle of the instrument for spectrum measurement of the target is as follows: the acquisition and processing computer 6 is turned on, and after the working band, resolution and sampling working mode are selected, the electrically controlled adjustable diaphragm 9 is automatically adjusted to the optimal opening size. For the laser interference module, the light emitted by the laser 1 is divided into two beams after passing through the semi-reflective and semi-transparent area 25 of the beam splitter 11. One beam is reflected on the front surface of the semi-reflective and semi-transparent area 25 and enters the reflector 12 located on the linear motor 16. After N times of refraction and reflection by the parallel plate, it is vertically incident on the beam splitter 11. After being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam A1 and a transmitted light beam A2; the other beam passes through the semi-reflective and semi-transparent area 25 and the anti-reflective surface 26 and enters the fixed reflector 14. After N times of refraction and reflection by the parallel plate, it is vertically incident on the beam splitter 11. After being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam B1 and a transmitted light beam B2; the transmitted light beam A2 and the reflected light beam B1 generate a laser interference signal 36, as shown in the attached manual. Figure 6As shown, when the linear motor 16 moves a distance δ1 that satisfies equation (6), the laser interference is constructive, and when the linear motor 16 moves a distance δ1 that satisfies equation (7), the laser interference is destructive, where m is an integer and λ is laser is the operating wavelength of the laser 1, N is the number of times the light emitted by the laser 1 is refracted in the parallel plate, and β is the angle β between the beam splitter 11 and the light emitted by the laser 1.

[0023]

[0024] The laser interference signal generated by the transmitted light beam A2 and the reflected light beam B1 is collected by the laser detector 4, and after the zero-crossing sampling processing of the control acquisition processing computer 6, a set of sampling pulse signals 37 with an optical path difference period of T is formed, as shown in the appendix of the specification. Figure 6 As shown, where λ laser is the operating wavelength of laser 1, N is the number of times the light emitted by laser 1 is refracted in the parallel plate, and β is the angle β between the beam splitter 12 and the light emitted by laser 1;

[0025]

[0026] For the measurement interference module, the parallel light emitted by the target to be measured at infinity passes through the primary concave reflector 8 of the Cassegrain telescope and then passes through the secondary plane reflector 7 to enter the focal position. After being spatially filtered by the electrically controlled adjustable aperture 9, it is collimated by the confocal axial parabolic reflector 10 and enters the semi-reflective and semi-transparent area 25 of the beam splitter 11 and is divided into two beams. One beam is reflected on the front surface of the semi-reflective and semi-transparent area 25 and enters the reflector 12 located on the linear motor 16. After being reflected by the reflector 12, it enters the beam splitter 11 vertically. 1, after being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam C1 and a transmitted light beam C2; the other beam passes through the semi-reflective and semi-transparent area 25 and the anti-reflection surface 26 and enters the fixed reflector 13, is reflected by the fixed reflector 13, vertically enters the beam splitter 11, and after being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam D1 and a transmitted light beam D2; the transmitted light beam C2 and the reflected light beam D1 generate an interference signal 38, as shown in the appendix of the specification. Figure 5 As shown, the detector module 5 samples the interference signal generated by the measurement interference module according to the sampling pulse signal generated by the laser interference module 39, and obtains a set of discrete signals 40 that meet the Nyquist sampling theorem, as shown in the appendix of the specification. Figure 6 As shown, the spectrum information of the target to be measured is obtained through data processing by the control acquisition processing computer 6.

[0027] Compared with the existing technology, a long-distance, high-precision 2N-times-of-the-light-path sampling Fourier spectrometer device has the following advantages: First, compared with the Nyquist sampling based on the equal-interval movement of the stepping motor, the Fourier spectrometer device with 2N-times-of-the-light-path sampling has the advantages of equal sampling intervals and high spectral inversion accuracy; Second, compared with the Nyquist sampling based on the n-fold frequency of the laser interferometer clock sequence, the electronics of the Fourier spectrometer device with 2N-times-of-the-light-path sampling does not introduce additional noise and time delay, and the spectral inversion accuracy is high; Third, the Fourier spectrometer device with 2N-times-of-the-light-path sampling can selectively increase the number of samples of the measuring interferometer, which is beneficial to the data processing method to reduce the noise of the system and improve the signal-to-noise ratio of the instrument; Fourth, the core interference module sampling folded self-loop design of the Fourier spectrometer device with 2N-times-of-the-light-path sampling has the advantages of simple structure and small size. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a Fourier spectrometer device with long-distance, high-precision 2N-times optical path sampling;

[0029] Figure 2 This is a schematic diagram of the core interference module;

[0030] Figure 3 This is a schematic diagram of the detector module;

[0031] Figure 4 This is a schematic diagram of the core interferometer module beam splitter partitioning;

[0032] Figure 5 Schematic diagram of the instrument workflow;

[0033] Figure 6 Schematic diagram of the discrete interference signal acquisition process. DETAILED DESCRIPTION

[0034] The following is attached with the instruction manual Figure 1 、 2 , 3, 4, 5, 6, further illustrate the present invention.

[0035] Example 1: A Fourier spectrometer device with long-distance, high-precision 8-times optical path sampling

[0036] The present invention adopts the following structure:

[0037] 1. Laser 1 uses a highly stable solid-state laser with an operating wavelength of 1064 nm, a divergence angle of 1 mrad, and a spot size of 2 mm.

[0038] 2. Small field of view observation telescope 2, plane mirror 7, concave mirror 8, electrically controlled adjustable aperture 9, and off-axis parabolic mirror 10 are coaxial. Plane mirror 7 is an Edmund Optics off-the-shelf product, model #64-021, with a wavelength range of 700-10000nm; concave mirror 8 is an Edmund Optics off-the-shelf product, model #64-021, with a wavelength range of 700-10000nm; electrically controlled adjustable aperture 9 is a custom product with an adjustable aperture of 0.5mm-15mm; off-the-axis parabolic mirror 10 is an Edmund Optics off-the-shelf product, model #43-336, with a focal length of 25.4mm.

[0039] 3. Interference module 3 is integrated and manufactured by Shanghai Zhongke Hangpu Optoelectronics Technology Co., Ltd. The aperture D of beam splitter 11 is 94 mm; the angle β between beam splitter 11 and the output light of laser 1 is 45°; the angle α between the incident light of laser 1 and plane reflector 15 is 67.5°; the spacing d between the parallel plates is 5 mm; the length l of small plane reflector 16 is 14.5 mm; the initial position X of reflector 12 is 40 mm; the length b of transflective surface 25 is 28.28 mm; the maximum travel L of linear motor is 1. max is 40 mm; the length a of the plane reflector 14 is 40 mm; the aperture D of the beam splitter 11 satisfies equation (4), and the length b of the semi-reflective surface 25 satisfies equation (5). According to equation (2), the spectral resolution of the instrument is 0.15 cm -1 .

[0040] 4. Laser detector 4 is a DSi series silicon photodetector provided by Pioneer Technology, model DSi200, with an effective photosensitive surface of 100mm 2 .

[0041] 5. Detector module 5 is integrated and manufactured by Shanghai Zhongke Hangpu Optoelectronics Technology Co., Ltd. The off-axis parabolic reflector 19 is an Edmund Optics off-the-shelf product, model #36-598, with a focal length of 177.8 mm. The shortwave color separation plate 20 uses a visible quartz beam splitter with an operating wavelength range of 0.35-2.8 μm. The mediumwave color separation plate 21 uses a KBr beam splitter with an operating wavelength range of 2-5 μm. The shortwave detector 22 uses a silicon photodetector, model SiD510. The mediumwave detector 23 uses an MCT detector, model MCT D313. The longwave detector 24 uses a heterojunction detector, model SiB D320.

[0042] 6. The control, acquisition and processing computer 14 adopts a HP computer, model i5-7300HQ.

[0043] The main working process of the present invention is:

[0044] 1. Open the instrument's control, acquisition, and processing computer 6 and power on the instrument.

[0045] 2. Select the required working band, resolution and sampling working mode. At this time, the control acquisition processing computer 6 sends instructions to make the electrically controlled adjustable diaphragm 9 automatically adjust to the optimal opening size according to the set resolution.

[0046] 3. Instrument self-test. If the instrument self-test reports an error, process it according to the prompts and restart the control, acquisition and processing computer 6. If the instrument self-test passes, proceed to the next step.

[0047] 4. Collect background.

[0048] 5. Perform spectral measurement on the target to be measured. At this time, for the laser interference module, the light emitted by the laser 1 is divided into two beams after passing through the semi-reflective and semi-transparent area 25 of the beam splitter 11. One beam is reflected on the front surface of the semi-reflective and semi-transparent area 25 and enters the reflector 12 located on the linear motor 16. After being refracted and reflected by the parallel plate N times (N is 4 in the design of the embodiment), it is vertically incident on the beam splitter 11. After being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam A1 and a transmitted light beam A2; the other beam passes through the semi-reflective and semi-transparent area 25 and the anti-reflective surface 26 and enters the fixed reflector 13. After being refracted and reflected by the parallel plate N times (N is 4 in the design of the embodiment), it is vertically incident on the beam splitter 11. After being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam B1 and a transmitted light beam B2; the transmitted light beam A2 and the reflected light beam B1 generate a laser interference signal 36, as shown in the attached manual. Figure 6 As shown, when the linear motor 16 moves a distance δ1 that satisfies equation (6), the laser interference is constructive, and when the linear motor 16 moves a distance δ1 that satisfies equation (7), the laser interference is destructive, where m is an integer and λ is laser is the operating wavelength of the laser 1, N is the number of times the light emitted by the laser 1 is refracted in the parallel plate (in the embodiment, N is 4), and β is the angle β between the beam splitter 11 and the light emitted by the laser 1. The laser interference signal generated by the transmitted light beam A2 and the reflected light beam B1 is collected by the laser detector 4, and after zero-crossing sampling processing by the control acquisition processing computer 6, a set of sampling pulse signals 37 with an optical path difference period of T is formed, as shown in the appendix of the specification. Figure 6As shown. For the measurement interferometer module, the parallel light emitted by the target to be measured at infinity passes through the primary concave reflector 8 of the Cassegrain telescope and then passes through the secondary plane reflector 7 to enter the focal position. After being spatially filtered by the electrically controlled adjustable aperture 9, it is collimated by the confocal axial parabolic reflector 10 and enters the semi-reflective and semi-transparent area 25 of the beam splitter 11 and is split into two beams. One beam is reflected by the front surface of the semi-reflective and semi-transparent area 25 and enters the reflector 12 located on the linear motor 16. After being reflected by the reflector 12, it enters the beam splitter 1 at normal incidence. 1, after being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam C1 and a transmitted light beam C2; the other beam passes through the semi-reflective and semi-transparent area 25 and the anti-reflection surface 26 and enters the fixed reflector 13, is reflected by the fixed reflector 13, vertically enters the beam splitter 11, and after being reflected by the reflective surface 28 of the beam splitter 11, it returns to the original path and enters the beam splitter 11 again, generating a reflected light beam D1 and a transmitted light beam D2; the transmitted light beam C2 and the reflected light beam D1 generate an interference signal 38, as shown in the appendix of the specification. Figure 4 As shown, the detector module 5 samples the interference signal generated by the measurement interference module according to the sampling pulse signal generated by the laser interference module 39, and obtains a set of discrete signals 40 that meet the Nyquist sampling theorem, as shown in the appendix of the specification. Figure 6 As shown, the spectrum information of the target to be measured is obtained through data processing by the control acquisition processing computer 7.

[0049] 6. Turn off the device after the measurement is completed.

Claims

1. A Fourier spectrometer device for optimizing laser sampling wavelength, characterized by: The Fourier spectrometer device comprises an ultra-stable laser (1), a small field observation telescope (2), an interference module (3), a laser detector (4), a detector module (5), and a control, acquisition, and processing computer (6); The small-field observation telescope (2) is composed of a plane reflector (7), a concave reflector (8), an electrically controlled adjustable iris (9), and an off-axis parabolic reflector (10) and is coaxial; the plane reflector (7) is located in front of the concave reflector (8), the electrically controlled adjustable iris (9) is located at the focus of the concave reflector (8), and is also located at the focus of the off-axis parabolic reflector (10); the opening size of the electrically controlled adjustable iris (9) is intelligently controlled by a control acquisition processing computer (6) according to the spectral resolution of the system, and the opening diameter φ of the electrically controlled adjustable iris (9) is proportional to the spectral resolution ν of the system and the maximum wave number σ of the working band. max , and the focal length f′ of the off-axis parabolic reflector (10) satisfies the following constraint: The maximum spectral resolution of the Fourier spectrometer device is ν max , and the maximum stroke L of the linear motor max , the relationship between the angle β between the beam splitter (11) and the incident light of the laser (1) satisfies: The beam splitter (11) comprises four different functional surface areas, a semi-reflective surface (25), an anti-reflective surface (26), an anti-reflective surface (27), and a reflecting surface (28); the radius R of the beam splitter (11) and the initial position L1 of the reflector (12), the maximum stroke L of the linear motor max , the length l1 of the plane reflector (14), the angle β between the beam splitter (11) and the incident light of the laser (1), and the angle α between the incident light of the laser (1) and the plane reflector (14) satisfy the following constraint relationship: R≥(L1+L max )sinβ+l1 sinα The constraint relationship between the length l2 of the semi-reflective surface (25), the initial position L1 of the reflector (12), and the angle β between the beam splitter (11) and the incident light of the laser (1) satisfies: l2=L1 sinβ; The interference module (3) is composed of a beam splitter (11), a fixed reflector (13), a linear motor (16), and a reflector (12) fixed on the linear motor; the reflector (12) is identical to the fixed reflector (13), and the positions of the reflector (12) at zero position and the fixed reflector (13) are symmetrical about the semi-reflective and semi-transparent surface (25) of the beam splitter (11); the fixed reflector 13 includes a plane reflector (14) and a small plane reflector (15), and the small plane reflector (15) and the end of the plane reflector (14) constitute a parallel plate internal reflector; the constraint relationship between the length l of the small plane reflector (15), the multiple n of the sampling optical path difference, the spacing d of the parallel plates, and the angle α between the incident light of the laser (1) and the plane reflector (14) satisfies: When in use, the light emitted by the laser is split into two beams after passing through the semi-reflective and semi-transparent area (25) of the beam splitter (11), one of which is reflected by the front surface of the semi-reflective and semi-transparent area (25) and enters the reflector (12) located on the linear motor (16), and after being refracted and reflected N times by the parallel plate, it is perpendicularly incident on the beam splitter (11), and after being reflected by the reflective surface (28) of the beam splitter (11), it returns to the original path and enters the beam splitter (11) again, thereby generating a reflected light beam A1 and a transmitted light beam A2; the other beam passes through the semi-reflective and semi-transparent area (25) and the anti-reflective surface (26) and enters the fixed reflector (13), and after being refracted and reflected N times by the parallel plate, it is perpendicularly incident on the beam splitter (11), and after being reflected by the reflective surface (28) of the beam splitter (11), it returns to the original path and enters the beam splitter (11) again, thereby generating a reflected light beam B1 and a transmitted light beam B2; the transmitted light beam A2 and the reflected light beam B1 generate a laser interference signal (36); For the measurement interference module, parallel light emitted by the target to be measured at infinity passes through the primary concave reflector (8) and then the secondary plane reflector (7) to enter the focal position, is spatially filtered by the electrically controlled adjustable aperture (9), is collimated by the confocal axial parabolic reflector (10), and then enters the semi-reflective and semi-transparent area (25) of the beam splitter (11) and is split into two beams, one of which is reflected by the front surface of the semi-reflective and semi-transparent area (25) and enters the reflector (12) located on the linear motor (16), is reflected by the reflector (12) and vertically enters the beam splitter (11), is reflected by the reflective surface (28) of the beam splitter (11), and then returns to the original path and enters the beam splitter (11) again, generating a reflected light beam C1 and a transmitted light beam C2; Another beam passes through the semi-reflective and semi-transparent area (25) and the anti-reflection surface (26) and enters the fixed reflector (13), is reflected by the fixed reflector (13), vertically enters the beam splitter (11), is reflected by the reflective surface (28) of the beam splitter (11), and then returns to the original path and enters the beam splitter (11) again, generating a reflected light beam D1 and a transmitted light beam D2; the transmitted light beam C2 and the reflected light beam D1 generate an interference signal (38); the detector module (5) samples the interference signal generated by the measurement interference module according to the sampling pulse signal generated by the laser interference module (39), and obtains a set of discrete signals (40) that meet the Nyquist sampling theorem, and obtains the spectral information of the target to be measured through data processing by the control acquisition processing computer (7).

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