A passive probe Fourier spectrometer device with laser 2N times optical path sampling

Abstract

The application discloses a kind of passive detection type Fourier spectrometer devices of laser 2N times optical path sampling.The device is based on Nyquist sampling theorem, equal inclination interference technology and self-alignment technology, core interference module uses laser interferometer and target signal interferometer common optical path design, through the design of aperture division of beam splitter, the parallel flat design of laser interference arm plane mirror, the self-alignment design of beam splitter and interference arm, 2N times return is introduced in laser interference optical path to obtain 2N times sampling optical path, to increase the selectable wavelength range of laser, 2N times optical path sampling laser interferometer provides the sampling pulse of target interferometer, obtains the redundant discrete intensity value of target, obtains the spectral information of target by Fourier transformation, to improve the signal-to-noise ratio of signal inversion, suitable for Fourier spectrometer field.

Description

[0001] The Fourier spectrometer device involved in this invention is a passive detection Fourier spectrometer device with n-fold optical path sampling. Based on the Nyquist sampling theorem, equal-inclination interferometry, and self-alignment techniques, the core interferometer module employs a shared optical path design for the laser interferometer and the target signal interferometer. Through beam splitting aperture design, parallel plate design of the laser interferometer arm plane mirror, and loop design of the beam splitter and interferometer arm, 2N folds are introduced into the laser interferometer optical path to obtain 2N times the sampling optical path, thereby increasing the selectable wavelength range of the laser. The 2N-fold optical path sampling laser interferometer provides sampling pulses to the target interferometer, obtaining redundant discrete intensity values ​​of the target. Spectral information of the target is obtained through Fourier transform, thereby improving the signal-to-noise ratio of signal inversion. This invention is applicable to the field of Fourier spectrometers. Background Technology

[0002] Fourier transform spectroscopy has the advantages of multi-channel, high throughput, and high resolution, and has wide applications in materials, life sciences, and pharmaceuticals.

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

[0004] The Fourier spectrometer employs a design where the laser interferometer and the target interferometer share the same optical path, meaning they have equal optical path lengths. The laser frequency selection for the laser interferometer must satisfy the Nyquist sampling theorem; that is, for a Fourier spectrometer with a spectral range of (λ1, λ2), the wavelength of the sampling laser must be less than half the shortest wavelength in the instrument's spectral range, i.e., less than or equal to... For infrared Fourier spectrometers with operating wavelengths greater than 1.5 μm, the laser wavelength required to satisfy the Nyquist sampling theorem must be less than 0.75 μm, and stable helium-neon lasers (632.8 nm) are commonly used. However, as the operating wavelength of Fourier spectrometers extends into the visible range, the wavelength of the sampling laser extends into the ultraviolet range, which brings difficulties to the selection of lasers.

[0005] There are two existing solutions to the sampling difficulties of laser interferometers in visible Fourier spectrometers. The first is to use a stepper motor, achieving Nyquist sampling through the equally spaced movements of the stepper motor. This solution uses a cross-roll bearing as the core component of the stepper motor, which wears down with movement, affecting the instrument's lifespan and measurement accuracy. Furthermore, the random deviation in the step size repeatability of the stepper motor leads to non-equidistant optical path sampling, causing distortion in the inverted interferogram. The second solution is to perform n-fold frequency harmonics on the original laser-generated clock sequence to achieve Nyquist sampling. This solution increases the complexity of the electronics and adds delays to the circuitry, causing target sampling to lag and resulting in distortion in the inverted interferogram.

[0006] The main drawbacks of the aforementioned existing technologies are as follows: First, Nyquist sampling based on the equal-interval movement of stepper motors is limited by the repeatability deviation of the step size, which will cause distortion of the inverted interferogram. At the same time, the unavoidable frictional wear of the cross roller bearings of the stepper motor will affect the lifespan and measurement accuracy of the instrument. Second, Nyquist sampling based on the nth harmonic of the laser interferometric clock sequence is subject to circuit delays and noise caused by the sampling itself, which will cause distortion of the inverted interferogram. Summary of the Invention

[0007] To address the aforementioned shortcomings of existing technologies, this invention provides a passive detection Fourier spectrometer device with n-fold optical path sampling, applicable to fields such as Fourier spectrometer development and spectral analysis.

[0008] The technical solution of the present invention is as follows:

[0009] A passive probe Fourier spectrometer device for laser 2N-times optical path sampling includes an ultra-stable laser 1, an ultra-wideband parallel light source 2, an interference module 3, a sample chamber 4, a laser detector 5, a detector module 6, and a control and processing computer 7, arranged sequentially according to the optical path transmission. The ultra-wideband parallel light source 2 is composed of a broadband emitter 8, an ellipsoidal reflector 9, an electrically adjustable aperture 10, and an off-axis parabolic reflector 11, all coaxial. The interference module 3 consists of a beam splitter 12, a fixed reflector 14, a linear motor 17, and a reflector 13 fixed on the linear motor, as shown in the attached specification. Figure 1 As shown.

[0010] The broadband light emitter 8 is located at the first focal point of the ellipsoidal reflector bowl 9, and the electrically controlled adjustable aperture 10 is located at the second focal point of the ellipsoidal reflector bowl 9. The off-axis parabolic mirror 11 is confocal with the second focal point of the ellipsoidal reflector bowl 9. The aperture size of the electrically controlled adjustable aperture 10 is intelligently controlled by the control acquisition and processing computer 7 according to the spectral resolution of the system. The aperture diameter φ of the electrically controlled adjustable aperture 10 is related to the spectral resolution ν of the system and the maximum wavenumber σ of the working band. maxThe constraint relationship between φ and the focal length f′ of the off-axis parabolic mirror 11 satisfies equation (1), where φ is the aperture diameter of the electrically controlled adjustable aperture 10, f′ is the focal length of the off-axis parabolic mirror 11, ν is the spectral resolution of the system, and σ max This is the maximum wavenumber for the operating band.

[0011]

[0012] The passive detection Fourier spectrometer device with 2N times sampling employs single-sided sampling, and its maximum spectral resolution ν max The maximum stroke L of the linear motor max The relationship between the angle β between beam splitter 12 and the incident laser beam 1 satisfies equation (2), where ν max L represents the maximum spectral resolution of a passively detected Fourier spectrometer with 2N times sampling. max β is the maximum stroke of the linear motor, and β is the angle between beam splitter 12 and the incident light from laser 1, as shown in the instruction manual. Figure 2 As shown.

[0013]

[0014] The reflector 13 is identical to the fixed reflector 14, and the positions of the reflector 13 at the zero position and the fixed reflector 14 are symmetrical about the upper surface of the beam splitter 12; the fixed reflector 14 includes a plane reflector 15 and a small plane reflector 16, the ends of the small plane reflector 16 and the plane reflector 15 forming a parallel plate internal reflector, as shown in the attached specification. Figure 2 As shown; the constraint relationship between the length l of the small plane mirror 16, the number of reflections N of the laser between the parallel plates, the distance d between the parallel plates, and the angle α between the incident laser beam 1 and the plane mirror 15 satisfies equation (3), where N is the number of reflections of the laser between the parallel plates, l is the length of the small plane mirror 16, d is the distance between the parallel plates, and α is the angle between the incident laser beam 1 and the plane mirror 15, as shown in the attached manual. Figure 2 As shown.

[0015]

[0016] The detector module 6 can select different detectors depending on the operating wavelength. If the instrument's operating wavelength is 2-15μm, then the detector module 6 has shortwave, medium wave, and long wave detection capabilities, as shown in the attached instruction manual. Figure 3 As shown, the detector module 6 includes an off-axis parabolic reflector 20, a short-wave dichroic filter 21, a mid-wave dichroic filter 22, a short-wave detector 23, a mid-wave detector 24, and a long-wave detector 25, which are placed sequentially according to the optical path transmission.

[0017] The beam splitter 12 comprises four different functional surface regions, as shown in the attached specification. Figure 4 As shown, there is a semi-reflective surface 26, an anti-reflective surface 27, an anti-reflective surface 28, and a reflective surface 29; the diameter D of the beam splitter 12 is relative to the initial position X of the reflector 13, and the maximum stroke L of the linear motor is... max The constraint relationship between the length a of the plane mirror 15, the angle β between the beam splitter 12 and the incident light of laser 1, and the angle α between the incident light of laser 1 and the plane mirror 15 satisfies equation (4); the constraint relationship between the length b of the semi-reflective surface 26, the initial position X of the mirror 13, and the angle β between the beam splitter 12 and the incident light of laser 1 satisfies equation (5), where D is the diameter of the beam splitter 12, X is the initial position of the mirror 13, and L is the diameter of the mirror 15. max α is the maximum stroke of the linear motor, a is the length of the plane mirror 15, β is the angle between the beam splitter 12 and the incident light of the laser 1, α is the angle between the incident light of the laser 1 and the plane mirror 15, and b is the length of the semi-reflective surface 26.

[0018] D≥(X+L max sinβ + asinα (4)

[0019] b=X sinβ (5)

[0020] The sample chamber 4 includes two measurement structures: a transmission measurement structure and a reflection measurement structure, which can be selected according to the measurement requirements. The transmission measurement structure is shown in the attached instruction manual. Figure 5 As shown, sample holder 30 is placed in the optical path. The reflective measurement structure is as per the instruction manual. Figure 6 As shown, the reflective measurement module 31 includes a plane mirror 32, a plane mirror 33, a sample holder 34, a plane mirror 35, and a plane mirror 36, which are placed sequentially according to the optical path transmission.

[0021] The working principle of this invention is as follows:

[0022] The instrument's operating procedure is as follows, as shown in the instruction manual. Figure 7 As shown, first, select the measurement mode and place the test accessory according to the optical characteristics of the sample to be tested: transmission or reflection. Second, turn on the instrument's control acquisition and processing computer 7 to power on the instrument. Third, select the required working band, resolution, and sampling mode. Fourth, the instrument performs a self-test. If the self-test reports an error, follow the prompts to resolve the issue and restart the control acquisition and processing computer 7. If the self-test passes, proceed to the next step. Fifth, acquire the background. Sixth, place the sample to be tested. For transmission measurement, place the sample in sample holder 30; for reflection measurement, install the reflection measurement module 31 in the sample chamber 4 and place the sample in sample holder 34. Seventh, perform spectral measurement on the target. Eighth, power off the instrument after measurement.

[0023] The principle of the instrument for spectral measurement of the target is as follows: After the control acquisition and processing computer 7 is turned on and the working band, resolution and sampling mode are selected, the electronically controlled adjustable aperture 10 is automatically adjusted to the optimal aperture size. For the laser interference module, the light emitted by laser 1 is split into two beams after passing through the semi-reflective region 26 of beam splitter 12. One beam is reflected by the front surface of the semi-reflective region 26 and enters the reflector 13 located on the linear motor 17. After N refractions and reflections by the parallel plate, it is incident perpendicularly on beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, it returns along the same path and is incident on beam splitter 12 again, generating a reflected beam A1 and a transmitted beam A2. The other beam passes through the semi-reflective region 26 and the anti-reflection surface 27 and enters the fixed reflector 15. After N refractions and reflections by the parallel plate, it is incident perpendicularly on beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, it returns along the same path and is incident on beam splitter 12 again, generating a reflected beam B1 and a transmitted beam B2. The transmitted beam A2 and the reflected beam B1 generate a laser interference signal 37, as shown in the attached manual. Figure 8 As shown, when the linear motor 17 moves a distance δ1 that satisfies equation (6), the laser interference is constructive; when the linear motor 17 moves a distance δ1 that satisfies equation (7), the laser interference is destructive, where m is an integer and λ is a constant. laser Where λ is the operating wavelength of laser 1, N is the number of times the emitted light of laser 1 is reflected in the parallel plate, and β is the angle β between beam splitter 12 and the emitted light of laser 1.

[0024]

[0025]

[0026] The laser interference signals generated by the transmitted beam A2 and the reflected beam B1 are collected by the laser detector 5. After zero-crossing sampling processing by the control acquisition and processing computer 7, a set of sampling pulse signals 38 with an optical path difference period of T is formed, as shown in the attached instruction manual. Figure 8 As shown, where λ laser Where λ is the operating wavelength of laser 1, N is the number of times the emitted light of laser 1 is reflected in the parallel plate, and β is the angle β between beam splitter 12 and the emitted light of laser 1.

[0027]

[0028] For the measurement interferometer module, the light emitted by the broadband light source 8 at the first focal point of the ellipsoidal reflector 9 is reflected by the ellipsoidal reflector 9 and converges to the second focal point of the ellipsoidal reflector 9. After spatial filtering by the electrically adjustable aperture 10 and collimation by the confocal axial parabolic reflector 11, the light enters the semi-reflective region 26 of the beam splitter 12 and is split into two beams. One beam is reflected by the front surface of the semi-reflective region 26 and enters the reflector 13 located on the linear motor 17. After reflection by the reflector 13, the light is perpendicularly incident on the beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, the beam returns along the same path and re-enters beam splitter 12, generating a reflected beam C1 and a transmitted beam C2. Another beam passes through the semi-reflective region 26 and the anti-reflective surface 27 into the fixed reflector 14, is reflected by the fixed reflector 14, and is perpendicularly incident on beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, the beam returns along the same path and re-enters beam splitter 12, generating a reflected beam D1 and a transmitted beam D2. The transmitted beam C2 and the reflected beam D1 generate an interference signal 39, as shown in the attached instruction manual. Figure 5 As shown, detector module 6 samples the interference signal generated by measurement interference module 40 based on the sampling pulse signal generated by laser interference module, obtaining a set of discrete signals 41 that satisfy the Nyquist sampling theorem, as shown in the appendix to the manual. Figure 8 As shown, the spectral information of the target to be measured is obtained through data processing by the control acquisition and processing computer 7.

[0029] Compared with existing technologies, a passive detection Fourier spectrometer device with laser 2N optical path sampling has the following advantages: 1. Compared with Nyquist sampling based on stepper motors moving at equal intervals, the passive detection Fourier spectrometer device with 2N optical path sampling has the advantages of equal sampling intervals and high spectral inversion accuracy; 2. Compared with Nyquist sampling based on the nth harmonic of a laser interference clock sequence, the passive detection Fourier spectrometer device with 2N optical path sampling does not introduce additional noise and time delay into its electronics, resulting in high spectral inversion accuracy; 3. The passive detection Fourier spectrometer device with 2N optical path sampling can selectively increase the number of samples in the measurement interferometer, which is beneficial for reducing system noise and improving the signal-to-noise ratio of the instrument; 4. The core interferometer module of the passive detection Fourier spectrometer device with 2N optical path sampling features a folded self-loop design, which has the advantages of simple structure and small size. Attached Figure Description

[0030] Figure 1 A schematic diagram of a passive detection Fourier spectrometer device for laser 2N-fold optical path sampling;

[0031] Figure 2 A schematic diagram of the core interference module is provided;

[0032] Figure 3 This is a schematic diagram of the detector module.

[0033] Figure 4 A schematic diagram of the beam splitter partitioning for the core interference module;

[0034] Figure 5 This is a schematic diagram of a transmission-type component;

[0035] Figure 6 This is a schematic diagram of a reflective component;

[0036] Figure 7 This is a schematic diagram of the instrument's workflow;

[0037] Figure 8 This is a schematic diagram of the discrete interferometric signal acquisition process. Detailed Implementation

[0038] The following is in conjunction with the instruction manual appendix. Figure 1 , 2 3, 4, 5, 6, 7, and 8 further illustrate the present invention.

[0039] Example 1: A passive detection Fourier spectrometer device with 8x optical path sampling

[0040] The present invention adopts the following structure:

[0041] 1. Laser 1 is a highly stable solid-state laser with a working wavelength of 1064nm, a divergence angle of 1mrad, and a spot size of 2mm.

[0042] 2. The ultra-wideband parallel light source 2 consists of a broadband light emitter 8, an ellipsoidal reflector 9, an electrically adjustable aperture 10, and an off-axis parabolic reflector 11, all coaxial. The broadband light emitter 8 is made of silicon carbide, heats up when powered, has a power of 20W, and radiates in the 1-20μm band; the ellipsoidal reflector 9 is an off-the-shelf product from Edmund Optics, model #68-797, with a first focal length of 14mm and a second focal length of 134mm; the electrically adjustable aperture 10 is a custom-made product with an adjustable aperture of 0.5mm-15mm; the off-axis parabolic reflector 11 is an off-the-shelf product from Edmund Optics, model #43-336, with a focal length of 25.4mm.

[0043] 3. Interference module 3 was integrated and manufactured by Shanghai Zhongke Hangpu Optoelectronic Technology Co., Ltd., wherein the aperture D of beam splitter 12 is 94mm; the angle β between beam splitter 12 and the emitted light of laser 1 is 45°; the angle α between the incident light of laser 1 and plane mirror 15 is 67.5°; the spacing d of the parallel plates is 5mm; the length l of small plane mirror 16 is 14.5mm; the initial position X of mirror 13 is 40mm; the length b of the semi-reflective surface 26 is 28.28mm; and the maximum stroke L of the linear motor is... maxThe length a of the plane mirror 15 is 40 mm; the aperture D of the beam splitter 12 satisfies equation (4), and the length b of the semi-reflective surface 26 satisfies equation (5). According to equation (2), the spectral resolution of the instrument is 0.15 cm⁻¹. -1 .

[0044] 4. Sample chamber 4 is manufactured by Wuxi Xinou Optoelectronic Technology Co., Ltd., and includes a transmission fixture and a reflection fixture.

[0045] 5. Laser detector 5 is a DSi series silicon photodetector, provided by Pioneer Technology, model DSi200, with an effective photosensitive area of ​​100mm. 2 .

[0046] 6. Detector module 6 is integrated and manufactured by Shanghai Zhongke Hangpu Optoelectronic Technology Co., Ltd. The off-axis parabolic reflector 20 is an off-the-shelf product from Edmund Optics, model #36-598, with a focal length of 177.8mm; the short-wave dichroic filter 21 is a visible quartz beam splitter with an operating wavelength range of 0.35-2.8μm; the mid-wave dichroic filter 22 is a KBr beam splitter with an operating wavelength range of 2-5μm; the short-wave detector 23 is a silicon photodetector, model SiD510; the mid-wave detector 24 is an MCT detector, model MCT D313; and the long-wave detector 25 is a heterojunction detector, model SiB D320.

[0047] 7. The control acquisition and processing computer 15 is an HP computer, model i5-7300HQ.

[0048] The main workflow of this invention is as follows:

[0049] 1. Select the measurement mode and place the test accessories according to the optical characteristics of the sample to be tested: transmission type or reflection type.

[0050] 2. Turn on the instrument's control, acquisition, and processing computer 7 to power on the instrument.

[0051] 3. Select the desired operating band, resolution, and sampling mode. At this time, the control acquisition and processing computer 7 sends a command to automatically adjust the electronically controlled adjustable aperture 10 to the optimal aperture size according to the set resolution.

[0052] 4. Instrument self-test. If the instrument self-test reports an error, follow the prompts to resolve the issue and restart the control acquisition and processing computer 7. If the instrument self-test passes, proceed to the next step.

[0053] 5. Background information collected.

[0054] 6. Place the sample to be tested. For transmission measurement, place the sample to be tested in the sample holder 30; for reflection measurement, install the reflection measurement module 31 in the sample chamber 4 and place the sample to be tested in the sample holder 34.

[0055] 7. Perform spectral measurement on the target. At this time, for the laser interferometer module, the light emitted by laser 1 is split into two beams after passing through the semi-reflective region 26 of beam splitter 12. One beam is reflected by the front surface of the semi-reflective region 26 and enters the reflector 13 located on the linear motor 17. After N refractions (N is 4 in this embodiment) through the parallel plate, it is incident perpendicularly on beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, it returns along the same path and is incident on beam splitter 12 again, generating a reflected beam A1 and a transmitted beam A2. The other beam passes through the semi-reflective region 26 and the anti-reflection surface 27 and enters the fixed reflector 15. After N refractions (N is 4 in this embodiment) through the parallel plate, it is incident perpendicularly on beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, it returns along the same path and is incident on beam splitter 12 again, generating a reflected beam B1 and a transmitted beam B2. The transmitted beam A2 and the reflected beam B1 generate a laser interference signal 37, as shown in the attached manual. Figure 8 As shown, when the linear motor 17 moves a distance δ1 that satisfies equation (6), the laser interference is constructive; when the linear motor 17 moves a distance δ1 that satisfies equation (7), the laser interference is destructive, where m is an integer and λ is a constant. laser Where λ is the operating wavelength of laser 1, N is the number of times the emitted light of laser 1 refracts in the parallel plate (N is 4 in this embodiment), and β is the angle β between beam splitter 12 and the emitted light of laser 1. The laser interference signals generated by the transmitted beam A2 and the reflected beam B1 are collected by laser detector 5, and after zero-crossing sampling processing by control acquisition and processing computer 7, a set of sampling pulse signals 38 with an optical path difference period of T is formed, as shown in the appendix to the specification. Figure 8As shown. For the measurement interferometer module, the light emitted by the broadband light source 8 at the first focal point of the ellipsoidal reflector 9 is reflected by the ellipsoidal reflector 9 and converges to the second focal point of the ellipsoidal reflector 9. After spatial filtering by the electrically adjustable aperture 10 and collimation by the confocal axial parabolic reflector 11, the light enters the semi-reflective and semi-transparent region 26 of the beam splitter 12 and is split into two beams. One beam is reflected by the front surface of the semi-reflective and semi-transparent region 26 and enters the reflector 13 located on the linear motor 17. After reflection by the reflector 13, the light is perpendicularly incident on the beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, the beam returns along the same path and re-enters beam splitter 12, generating a reflected beam C1 and a transmitted beam C2. Another beam passes through the semi-reflective region 26 and the anti-reflective surface 27 into the fixed reflector 14, is reflected by the fixed reflector 14, and is perpendicularly incident on beam splitter 12. After being reflected by the reflective surface 29 of beam splitter 12, the beam returns along the same path and re-enters beam splitter 12, generating a reflected beam D1 and a transmitted beam D2. The transmitted beam C2 and the reflected beam D1 generate an interference signal 39, as shown in the attached instruction manual. Figure 5 As shown, detector module 6 samples the interference signal generated by measurement interference module 40 based on the sampling pulse signal generated by laser interference module, obtaining a set of discrete signals 41 that satisfy the Nyquist sampling theorem, as shown in the appendix to the manual. Figure 8 As shown, the spectral information of the target to be measured is obtained through data processing by the control acquisition and processing computer 7.

[0056] 8. Turn off the machine after the measurement is completed.

Claims

1. A passive detection Fourier spectrometer device for laser 2N-fold optical path sampling, characterized in that: The passive detection Fourier spectrometer device includes an ultra-stable laser (1), an ultra-wideband parallel light source (2), an interference module (3), a sample chamber (4), a laser detector (5), a detector module (6), and a control acquisition and processing computer (7). The interference module (3) consists of a beam splitter (12), a fixed reflector (14), a linear motor (17), and a reflector (13) fixed on the linear motor. The reflector (13) is identical to the fixed reflector (14), and the positions of the reflector (13) at the zero position and the fixed reflector (14) are symmetrical about the semi-reflective surface (26) of the beam splitter (12). The fixed reflector (14) includes a large plane reflector (15) and a small plane reflector (16). The ends of the small plane reflector (16) and the plane reflector (15) form a parallel plate internal reflector. The length of the small plane reflector (16) is... Multiples of the sampling optical path difference Spacing between parallel plates The angle between the incident laser beam (1) and the plane mirror (15) The constraints between them satisfy: ； The beam splitter (12) includes four different functional surface regions: a semi-reflective surface (26), a first anti-reflective surface (27), a second anti-reflective surface (28), and a reflective surface (29). The diameter of the beam splitter (12) relative to the initial position of the reflector (13) Maximum stroke of linear motor The length of the plane mirror (15) The angle between the beam splitter (12) and the incident laser beam (1) The angle between the incident laser beam (1) and the plane mirror (15) The constraints between them satisfy: ； Length of the semi-reflective and semi-transparent surface (26) relative to the initial position of the mirror (13) The angle between the beam splitter (12) and the incident laser beam (1) The constraint relationship satisfies: ； The maximum spectral resolution of the Fourier spectrometer device With the maximum stroke of the linear motor The angle between the beam splitter (12) and the incident laser beam (1) The relationship between them satisfies: ； For the laser interference module, the light emitted by the laser (1) is split into two beams after passing through the semi-reflective and semi-transparent region (26) of the beam splitter (12). One beam is reflected by the front surface of the semi-reflective and semi-transparent region (26) and enters the reflector (13) located on the linear motor (17). After N refractions and reflections by the parallel plate, it is perpendicularly incident on the beam splitter (12). After being reflected by the reflective surface (29) of the beam splitter (12), it returns to the beam splitter (12) and is incident on the beam splitter (12) again, generating a reflected beam A1 and a transmitted beam A2. The other beam passes through the semi-reflective and semi-transparent region (26) and the first anti-reflection surface (27) and enters the fixed reflector (15). After N refractions and reflections by the parallel plate, it is perpendicularly incident on the beam splitter (12). After being reflected by the reflective surface (29) of the beam splitter (12), it returns to the beam splitter (12) and is incident on the beam splitter (12) again, generating a reflected beam B1 and a transmitted beam B2. The transmitted beam A2 and the reflected beam B1 generate a laser interference signal (37). When the linear motor (17) moves a distance satisfy When the laser interference is constructive, the linear motor (17) moves a distance... satisfy At that time, the laser interference is destructive, in which It is an integer. The working wavelength of laser (1) is... The number of times the laser beam (1) is reflected back in the parallel plate. The angle between the beam splitter (12) and the laser (1) output light; the laser interference signal generated by the transmitted beam A2 and the reflected beam B1 is collected by the laser detector (5), and after the zero-crossing sampling processing of the control acquisition and processing computer (7), a set of sampling pulse signals (38) with an optical path difference period of T is formed; for the measurement interference module, the light emitted by the broadband light source (8) located at the first focus of the ellipsoidal reflector (9) is reflected by the ellipsoidal reflector (9) and converges to the second focus of the ellipsoidal reflector (9). After spatial filtering by the electrically controlled adjustable aperture (10), and collimated by the confocal axial parabolic reflector (11), it enters the semi-reflective and semi-transparent region (26) of the beam splitter (12) and is split into two beams, one of which is in the semi-reflective and semi-transparent region. The beam is reflected from the front surface of (26) into the reflector (13) located on the linear motor (17), and after being reflected by the reflector (13), it is perpendicularly incident on the beam splitter (12). After being reflected by the reflective surface (29) of the beam splitter (12), it returns to the beam splitter (12) again, generating a reflected beam C1 and a transmitted beam C2. Another beam passes through the semi-reflective and semi-transparent region (26) and the first anti-reflection surface (27) into the fixed reflector (14). After being reflected by the fixed reflector (14), it is perpendicularly incident on the beam splitter (12). After being reflected by the reflective surface (29) of the beam splitter (12), it returns to the beam splitter (12) again, generating a reflected beam D1 and a transmitted beam D2. The transmitted beam C2 and the reflected beam D1 generate an interference signal (39).

2. The passive detection Fourier spectrometer device for laser 2N-times optical path sampling according to claim 1, characterized in that: The ultra-wideband parallel light source (2) consists of a broadband light emitter (8), an ellipsoidal reflector (9), an electrically adjustable aperture (10), and an off-axis parabolic mirror (11), all coaxial. The broadband light emitter (8) is located at the first focal point of the ellipsoidal reflector (9), and the electrically adjustable aperture (10) is located at the second focal point of the ellipsoidal reflector (9). The off-axis parabolic mirror (11) is confocal with the second focal point of the ellipsoidal reflector (9). The aperture size of the electrically adjustable aperture (10) is intelligently controlled by the control acquisition and processing computer (7) according to the spectral resolution of the system. The aperture diameter of the electrically adjustable aperture (10) is... With the system's spectral resolution Maximum wavenumber of the working band And the focal length of the off-axis parabolic mirror (11) The constraints between them satisfy: 。

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