Digital Micro-mirror Array Spectrometer and Its Measurement Method

Abstract

The present invention provides a digital micromirror array spectrometer and a measurement method thereof. The spectrometer includes: a light source system, a beam splitting system, a first digital micromirror array, a second digital micromirror array, and a detector system; the light source system is used to emit a parallel light beam and incident it into the beam splitting system; the beam splitting system is used to divide the parallel light beam into a first light beam and a second light beam that are perpendicular to each other; the first light beam and the second light beam respectively form two reflected light beams that are divided into M×M regions and have an optical path difference between adjacent regions after being reflected by the first digital micromirror array and the second digital micromirror array; the two reflected light beams return to the beam splitting system again for beam combination and interference, and then form an interference light beam including M×M interference light field units and incident it into the detector system to obtain an interference image array, thereby obtaining the spectral information of the parallel light beam. The present invention improves the real-time performance of spectral detection and has the characteristics of miniaturization, static state, and strong environmental adaptability.

Description

Technical Field

[0001] The present invention relates to the field of spectral technology, and particularly relates to a digital micromirror array spectrometer and a measurement method thereof. Background Art

[0002] Spectral technology can obtain the composition and content information of a target substance, and has been increasingly widely applied in fields such as physical experiments, chemical analysis, biological characterization, medical tests, ecological environment protection, etc., and plays an important role in the exploration and discovery of new materials, new energy sources, and the unknown world. In order to obtain the spectral characteristics of a target, it is necessary to decompose the detected polychromatic light spectroscopically. Currently, the commonly used spectral instruments mainly adopt technologies such as filter spectroscopy, prism spectroscopy, grating spectroscopy, and interference spectroscopy. Among them, the Fourier transform spectroscopy using interference spectroscopy technology has become a high-end instrument in many application fields due to its advantages such as multi-channel, high throughput, accurate wavenumber, and low stray light.

[0003] In recent years, with the emergence and development of emerging technology fields such as space exploration, aerial remote sensing, earth survey, atmospheric monitoring, and military reconnaissance, due to their special application fields and usage environments, there is an urgent need for miniaturized and static Fourier transform spectrometers. And with the continuous upgrading of the demand, it makes the traditional Fourier transform spectrometer encounter insurmountable technical bottlenecks. Currently, the Fourier transform spectrometers commonly used in laboratories adopt a time-modulated structure. The interferometer generates an optical path difference through the scanning of a moving mirror to obtain spectral information. It contains a set of high-precision moving mirror scanning mechanisms, and precise sampling of the interference pattern is carried out through the high-precision moving mirror scanning mechanisms. The mechanisms are very complex to manufacture, sensitive to vibration, relatively demanding on the usage environment, and the moving mirror scanning mechanisms have a large volume and weight. At the same time, due to the use of a beam splitter for spectroscopy, there will be an energy loss of half, reducing the stability and reliability of the system, which is not conducive to aerospace applications such as meteorological observation and atmospheric remote sensing. Thus, it limits its application in high-tech fields such as space exploration, meteorological remote sensing, and military reconnaissance. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to propose a digital micromirror array spectrometer and a measurement method thereof. By precisely adjusting the pitch angle and rotation angle of two digital micromirror arrays, precise control of the optical path difference of the light beam is achieved, solving the problems of large volume and weight, and low stability and reliability caused by the existence of a high-precision moving mirror drive system in a moving mirror scanning Fourier transform spectrometer. The present invention utilizes the spatial phase modulation technology of two digital micromirror arrays to perform distributed phase modulation on the incident light field, realizing synchronous sampling of the intensities of interference patterns at different sampling levels, and at the same time improving the real-time performance of spectral detection, which is beneficial to the detection of transient spectra. It has the characteristics of miniaturization, staticization, and strong environmental adaptability.

[0005] To achieve the above object, the present invention adopts the following specific technical solutions:

[0006] The present invention provides a digital micromirror array spectrometer, including: a light source system, a beam splitting system, a first digital micromirror array, a second digital micromirror array, and a detector system;

[0007] The light source system is used to emit a parallel light beam and incident it into the beam splitting system; the beam splitting system is used to divide the parallel light beam into a first light beam and a second light beam that are perpendicular to each other; the first light beam and the second light beam respectively form two reflected light beams that are divided into M×M regions and have an optical path difference between adjacent regions after being reflected by the first digital micromirror array and the second digital micromirror array; the two reflected light beams return to the beam splitting system again for beam combination and interference, and then form an interference light beam including M×M interference light field units and incident it into the detector system to obtain an interference image array and further obtain the spectral information of the parallel light beam.

[0008] Preferably, the light source system includes: a light source and a collimating mirror; the light source is used to emit a divergent light beam, and the divergent light beam is collimated by the collimating mirror to obtain a parallel light beam.

[0009] Preferably, the first digital micromirror array or the second digital micromirror array includes: M×M digital micromirror substrates, M×M digital micromirror units, M×M digital micromirror unit rotation axes, and a driving power supply;

[0010] The digital micromirror substrate supports the digital micromirror unit; there is a rotational connection between the digital micromirror substrate and the digital micromirror unit rotation axis; the digital micromirror unit rotation axis is fixedly connected to the digital micromirror unit, and the driving power supply is used to provide a driving force for the rotation of the digital micromirror unit, and drives the digital micromirror unit to rotate by driving the rotation of the digital micromirror unit rotation axis.

[0011] Preferably, the detector system includes: a beam reduction system and a area array detector;

[0012] The interference light beam including M×M interference light field units is incident into the area array detector after being reduced by the beam reduction system, and the area array detector is used to convert the interference light beam into an electrical signal to obtain an interference image array.

[0013] Preferably, the angle between the first digital micromirror array and the horizontal plane is θ, and the angle between the digital micromirror unit in the first digital micromirror array and the first digital micromirror array is θ, so that the first light beam is perpendicular to the digital micromirror unit; thus, the reflected light of the first light beam is reflected into the beam splitting system;

[0014] The angle between the second digital micromirror array and the horizontal plane is φ, and the angle between the digital micromirror unit in the second digital micromirror array and the second digital micromirror array is φ, so that the second light beam is perpendicular to the digital micromirror unit; thus, the reflected light of the second light beam is reflected into the beam splitting system;

[0015] The beam splitting system is a beam splitter; the angle between the beam splitter and the horizontal plane is 45°.

[0016] Preferably, in the interference light beams composed of M×M interference light field units, the optical path difference δ corresponding to the (i,j)-th interference light field unit is:

[0017] δ(i,j) = OP2(j) - OP1(i) = 2(jbsinφ - iasinθ)

[0018] The light passing aperture of the digital micromirror unit in the first digital micromirror array becomes acosθ; the light passing aperture of the digital micromirror unit in the second digital micromirror array becomes bcosφ; the size of each interference light field unit is acosθ×bcosφ;

[0019] where i = 0, 1…M; j = 0, 1…M;

[0020] a is the width of the digital micromirror unit in the first digital micromirror array;

[0021] b is the width of the digital micromirror unit in the second digital micromirror array.

[0022] Preferably, when the optical path difference sequence between adjacent regions in the M×M regions of the interference light beam is continuous, the first digital micromirror array and the second digital micromirror array achieve optical path mutual compensation and satisfy the following conditions:

[0023] a = b, sinφ = Nsinθ;

[0024] Or b = Na, φ = θ.

[0025] The present invention also provides a measurement method for a digital micromirror array spectrometer, including the following steps:

[0026] S1. A parallel light beam emitted by a light source system is incident on a beam splitter and is divided into a first light beam and a second light beam;

[0027] S2. The first light beam is incident on the first digital micromirror array after being reflected by the beam splitter; the second light beam is incident on the second digital micromirror array after being transmitted by the beam splitter;

[0028] S3. Adjust the pitch angle and rotation angle of the first digital micromirror array and the second digital micromirror array respectively until the first light beam and the second light beam are reflected by the first digital micromirror array and the second digital micromirror array and then return to the beam splitter again;

[0029] After the first light beam and the second light beam interfere in the beam splitter, an interference light beam including M×M interference light field units is incident on the detector system, and an interference image array is obtained, thereby acquiring the spectral information of the parallel light beam.

[0030] Preferably, in step S3, the adjustment process of the first digital micromirror array and the second digital micromirror array is as follows:

[0031] By observing whether the first digital micromirror array and the second digital micromirror array are mirror-symmetric with respect to the beam splitter and whether interference fringes are generated in the area array detector;

[0032] The adjustment process ends until the first digital micromirror array and the second digital micromirror array are mirror-symmetric with respect to the beam splitter and stable interference fringes are generated in the area array detector.

[0033] Preferably, after applying a driving voltage to the first digital micromirror array and the second digital micromirror array to rotate the digital micromirror units to a preset angle, the driving voltage distribution on the digital micromirror units in the first digital micromirror array and the second digital micromirror array is fixed.

[0034] Compared with the existing technology, the present invention replaces the fixed mirror and the scanning moving mirror of the traditional Fourier transform spectrometer with two digital micromirror arrays with orthogonal rotation axes, and controls the rotation angle of each digital micromirror unit by adjusting the driving voltages of the two digital micromirror arrays, thereby modulating the optical path delay between the reflected lights of each digital micromirror unit and realizing the two-dimensional spatial sampling of the optical path difference. The digital micromirror array spectrometer proposed in the present invention realizes the synchronous sampling of all sampled optical path difference interference patterns by driving the rotation of two orthogonal rotation axis digital micromirror arrays with voltages, improving the real-time performance of spectral detection; at the same time, it has a static structure, avoiding the difficulties in manufacturing and control caused by moving parts, improving the stability and reliability of the system, and reducing the volume and weight of the system. Description of the Drawings

[0035] Figure 1 is a schematic structural diagram of a digital micromirror array spectrometer according to an embodiment of the present invention.

[0036] Figure 2 is a schematic structural diagram of a digital micromirror array in a digital micromirror array spectrometer according to an embodiment of the present invention.

[0037] Figure 3 is a schematic diagram of the optical path modulation of the first digital micromirror array in a digital micromirror array spectrometer according to an embodiment of the present invention.

[0038] Figure 4 is a schematic diagram of the optical path modulation of the second digital micromirror array in a digital micromirror array spectrometer according to an embodiment of the present invention.

[0039] Figure 5 It is a schematic flowchart of the measurement method of the digital micromirror array spectrometer provided by an embodiment of the present invention.

[0040] Figure 6 It is a program block diagram of the measurement method of the digital micromirror array spectrometer provided by an embodiment of the present invention.

[0041] The reference numerals therein include: light source 1, collimator 2, beam splitter 3, first digital micromirror array 4, second digital micromirror array 5, beam reducing system 6, area array detector 7, digital micromirror substrate 8, digital micromirror unit 9, digital micromirror unit rotation axis 10, and drive voltage source 11. Detailed implementation manners

[0042] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.

[0043] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but do not constitute a limitation to the present invention.

[0044] Figure 1 It shows a schematic structural diagram of the digital micromirror array spectrometer provided by an embodiment of the present invention.

[0045] As Figure 1 shown, the digital micromirror array spectrometer provided by an embodiment of the present invention includes: a light source system, a beam splitting system, a digital micromirror array, and a detector system.

[0046] The light source system is used to emit a parallel light beam parallel to the z-axis, and the parallel light beam is incident into the beam splitting system.

[0047] The z-axis is parallel to the optical axis of the light source system, and the XYZ coordinate system is a right-handed coordinate system.

[0048] The light source system includes: a light source 1 and a collimator 2. The light source 1 serves as the radiation source of the digital micromirror array spectrometer and is used to emit a divergent light beam having a certain spectral radiation width. The divergent light beam is incident on the collimator and is collimated to obtain a parallel light beam parallel to the z-axis (i.e., parallel to the optical axis).

[0049] Figure 2 It shows a schematic structural diagram of the digital micromirror array in the digital micromirror array spectrometer provided by an embodiment of the present invention.

[0050] AsFigure 2 As shown, the digital micromirror array includes: a first digital micromirror array 4 and a second digital micromirror array 5. Both the first digital micromirror array 4 and the second digital micromirror array 5 are composed of the following elements: a digital micromirror substrate 8, a digital micromirror unit 9, a digital micromirror unit rotation axis 10, and a driving voltage source 11. The digital micromirror substrate 8 supports the digital micromirror unit; there is a rotational connection between the digital micromirror substrate 8 and the digital micromirror unit rotation axis 10; the surface of the digital micromirror unit 9 is coated with a high-reflection film, which is fixedly connected to the digital micromirror unit rotation axis 10 and can rotate around the digital micromirror unit rotation axis 10 through a driving voltage; the driving voltage source 11 is used to provide a driving force for the rotation of the digital micromirror unit 9.

[0051] The beam splitting system includes a beam splitter 3; the beam splitter 3 is placed at an angle of 45° with the optical axis, and the surface of the beam splitter 3 is coated with a semi-reflective and semi-transmissive film, which divides the parallel beam into a first beam and a second beam with equal energy. Among them, the first beam undergoes a 90° deflection after being reflected by the beam splitter 3 and is transmitted in a direction perpendicular to the optical axis to the first digital micromirror array 4, and the second beam is transmitted along the optical axis to the second digital micromirror array 5 after passing through the beam splitter 3.

[0052] Figure 3 It shows a schematic diagram of the optical path modulation of the first digital micromirror array in the digital micromirror array spectrometer provided by an embodiment of the present invention.

[0053] As Figure 3 shown, the first digital micromirror array 4 is located on the reflection optical path of the beam splitter 3 and has a certain pitch angle along the z-axis relative to the vertical plane of the optical axis. It is composed of M×M digital micromirror units 9, and each digital micromirror unit rotation axis 10 is along the z-axis direction, and by rotating, the reflection surfaces of the respective digital micromirror units 9 are perpendicular to the first beam.

[0054] For the first digital micromirror array 4, let the digital micromirror unit rotation axis be parallel to the horizontal plane, and the size of each digital micromirror unit is a. Place the first digital micromirror array 4 on the reflection optical path of the beam splitter 3, and the surface of the first digital micromirror array 4 has a pitch inclination angle of θ along the horizontal axis relative to the vertical plane of the optical axis. Then apply the same voltage to the digital micromirror units of the first digital micromirror array 4, adjust the voltage values of the respective digital micromirror units on the first digital micromirror array 4, so that all the digital micromirror units in each row of the first digital micromirror array 4 rotate by an angle of θ along the horizontal rotation axis relative to the surface of the first digital micromirror array 4, so that the reflection surfaces of the respective digital micromirror units are perpendicular to the optical axis of the first beam, thereby returning the reflected light of the first beam along the original path. The horizontal rotation of the digital micromirror units causes a specific displacement amount to be generated in the optical axis direction between the digital micromirror units in each row. The displacement amount between adjacent rows of digital micromirror units is asinθ.

[0055] After the reflected light of the first light beam is reflected by each digital micromirror unit, it returns along the original optical path. Therefore, the optical path delay generated by the digital micromirror unit in the i-th row is OP1(i) = 2iasinθ. Since the surface of the digital micromirror array is inclined at an angle θ along the horizontal axis, the light-transmitting aperture of each digital micromirror unit 9 becomes acosθ.

[0056] Figure 4 Fig. shows a schematic diagram of the optical path modulation of the second digital micromirror array in the digital micromirror array spectrometer provided by the embodiment of the present invention.

[0057] As Figure 4 shown, the second digital micromirror array 5 is located on the transmission optical path of the beam splitter 3 and has a certain rotation angle along the y-axis relative to the vertical plane of the optical axis. It is composed of M×M digital micromirror units 9, and the rotation axis 10 of each digital micromirror unit is along the y-axis direction, and the reflection surface of each digital micromirror unit 9 is made perpendicular to the second light beam through rotation.

[0058] For the second digital micromirror array 5, let the rotation axis of its digital micromirror unit be perpendicular to the horizontal plane, and the size of each digital micromirror unit is b. The second digital micromirror array 5 is placed in the transmission optical path of the beam splitter 3, and the surface of the second digital micromirror array 5 has a rotation inclination angle of φ along the vertical axis relative to the vertical plane of the optical axis. Then, the same voltage is applied to the digital micromirror units of the second digital micromirror array 5, and the voltage values on each digital micromirror unit of the second digital micromirror array 5 are adjusted so that all the digital micromirror units in each column of the second digital micromirror array 5 rotate by an angle of φ along the vertical rotation axis relative to the surface of the second digital micromirror array 5, so that the reflection surface of each digital micromirror unit is perpendicular to the second light beam, so that the transmitted light of the second light beam returns along the original path. The vertical rotation of the digital micromirror unit causes a specific displacement amount to be generated in the optical axis direction between the digital micromirror units in each column. The displacement amount between two adjacent columns of digital micromirror units is bsinφ.

[0059] After the transmitted light of the second light beam is reflected by each digital micromirror unit, it returns along the original optical path. Therefore, the optical path delay generated by the digital micromirror unit in the j-th column is OP2(j) = 2jbsinφ. Since the surface of the digital micromirror array is inclined along the vertical axis, the light-transmitting aperture of each digital micromirror becomes bcosφ.

[0060] The first digital micromirror array 4 and the second digital micromirror array 5 divide the interference light beam into M×M interference light field units in the transverse space. Each digital micromirror unit in the first digital micromirror array 4 and the second digital micromirror array 5 corresponds to a specific optical path difference. The optical path difference δ corresponding to the (i, j)-th interference light field unit is:

[0061] δ(i,j) = OP2(j) - OP1(i) = 2(jbsinφ - iasinθ)

[0062] where \(i = 0, 1, \ldots, M\); \(j = 0, 1, \ldots, M\);

[0063] The size of each interference light field unit is \(a\cos\theta\times b\cos\varphi\).

[0064] The first light beam and the second light beam reflected back by the first digital micromirror array 4 and the second digital micromirror array 5 are combined and superposed and interfere on the beam splitter 3 to form an interference light beam incident into the detector system.

[0065] The detector system includes: a beam reducing system 6 and a area array detector 7. The interference light beam including \(M\times M\) interference light field units is incident into the area array detector 7 after being reduced by the beam reducing system 6. The area array detector 7 is used to convert the interference light beam into an electrical signal to obtain an interference image array.

[0066] Therefore, the interference intensity \(I\) corresponding to the \((i, j)\)th image unit is:

[0067]

[0068] In the formula, \(\nu\) is the wave number of the interference optical signal. For light with a wavelength of \(\lambda\), \(\nu = 1 / \lambda\).

[0069] By performing discrete Fourier transform demodulation on the interference image array, the spectral information of the parallel light beam can be restored.

[0070] In order to form a continuous optical path difference sequence, the two digital micromirror arrays must achieve optical path mutual compensation, and there are two implementation methods.

[0071] One method is to keep the micromirror units of the two digital micromirror arrays having the same size \(a = b\), and achieve optical path complementarity by matching the tilt angles of the two digital micromirror arrays, so that the tilt angle of one digital micromirror array is \(N\) times the tilt angle of the other digital micromirror array, that is, \(\sin\varphi = N\sin\theta\). Another method is to achieve optical path complementarity by matching the micromirror unit sizes of the two digital micromirror arrays, so that the micromirror unit size of one digital micromirror array is \(N\) times the micromirror unit size of the other digital micromirror array, that is, \(b = Na\). At this time, the two digital micromirror arrays have the same tilt angle \(\varphi = \theta\).

[0072] When the first optical path complementary method is adopted, the micromirror units of the two digital micromirror arrays have the same size \(a = b\), and the tilt angle relationship between the two digital micromirror arrays is \(\sin\varphi = N\sin\theta\). At this time, the optical path difference sampling array is:

[0073] \(\delta(i, j)=2(jaN\sin\theta - i a\sin\theta)=2a\sin\theta(jN - i)\)

[0074] In order not to generate spectral aliasing during the spectral restoration process, the sampling interval of the optical path difference must be less than or equal to twice the minimum wavelength of the optical signal, that is:

[0075]

[0076] Therefore, the tilt angles of the two digital micromirror arrays must satisfy the following formula:

[0077]

[0078] At this time, the form of the restored spectrum B is:

[0079]

[0080] In the formula, ν is the wave number of the interfering optical signal. For light with a wavelength of λ, ν = 1 / λ.

[0081] According to the discrete Fourier transform theory, the spectral resolution of the system is

[0082] At this time, the size of each interfering optical field unit is

[0083] When the second optical path complementary method is adopted, the two digital micromirror arrays have the same tilt angle φ = θ, and the relationship between the micromirror unit sizes between the two digital micromirror arrays is b = Na. At this time, the optical path difference sampling array is:

[0084] δ(i,j) = 2(jNasinθ - iasinθ) = 2asinθ(jN - i)

[0085] In order not to generate spectral aliasing during the spectral restoration process, the sampling interval of the optical path difference must be less than or equal to twice the minimum wavelength of the optical signal, that is:

[0086]

[0087] Therefore, the tilt angles of the two digital micromirror arrays must satisfy the following formula:

[0088]

[0089] At this time, the form of the restored spectrum B is

[0090]

[0091] According to the discrete Fourier transform theory, the spectral resolution of the system

[0092] At this time, the size of each interfering optical field unit is acosθ × Nacosθ.

[0093] where λmin is the minimum wavelength in the parallel light beam.

[0094] Figure 5 The flowchart of the measurement method of the digital micromirror array spectrometer provided by an embodiment of the present invention is shown.

[0095] Figure 6 The program block diagram of the measurement method of the digital micromirror array spectrometer provided by an embodiment of the present invention is shown.

[0096] As Figure 5 and Figure 6 shown, the measurement method of the digital micromirror array spectrometer provided by an embodiment of the present invention includes the following steps:

[0097] Fix the collimator on the platform substrate; use a divergent laser light source with a wavelength within the working spectral band of the system as the incident light, adjust the distance between the laser light source and the collimator, so that the emission point of the laser light source is located on the front focal point of the collimator, and ensure that the outgoing light is collimated into a parallel light beam;

[0098] Place the beam splitter in the outgoing light path of the light source system at an angle of 45° with the optical axis, and perform central alignment.

[0099] S1. A parallel light beam emitted by the light source system is incident on the beam splitter and is divided into a first light beam and a second light beam.

[0100] S2. The first light beam is incident on the first digital micromirror array after being reflected by the beam splitter; the second light beam is incident on the second digital micromirror array after being transmitted by the beam splitter.

[0101] Place the first digital micromirror array in the reflection light path of the beam splitter and perform central alignment; place the second digital micromirror array in the transmission light path of the beam splitter and perform central alignment;

[0102] Adjust the relative position between the first digital micromirror array and the second digital micromirror array, observe whether the first digital micromirror array and the second digital micromirror array are mirror-symmetric with respect to the beam splitter, and whether interference fringes are generated in the area array detector; if they are not in the mirror-symmetric position or no interference fringes are generated, continue to adjust the relative position between the first digital micromirror array and the second digital micromirror array until the first digital micromirror array and the second digital micromirror array are mirror-symmetric with respect to the beam splitter and stable interference fringes are generated;

[0103] S3. Adjust the pitch angle and rotation angle of the first digital micromirror array and the second digital micromirror array respectively until the first light beam and the second light beam return to the beam splitter again after being reflected by the first digital micromirror array and the second digital micromirror array.

[0104] First, rotate the first digital micromirror array by a specific pitch angle along the horizontal axis; rotate the second digital micromirror array by a specific rotation angle along the vertical axis;

[0105] Secondly, by applying a driving voltage, adjust the rotation angle of each digital micromirror unit in the first digital micromirror array along the horizontal axis, and observe whether the reflective surface of each digital micromirror unit is perpendicular to the first light beam, that is, whether the reflected light beam of the first light beam returns along the original path; if the reflected light beam does not return along the original path, continue to adjust the driving voltage applied to the first digital micromirror array until the reflected light rays of each micromirror unit return along the original path;

[0106] By applying a driving voltage, adjust the rotation angle of each digital micromirror unit in the second digital micromirror array along the vertical axis, and observe whether the reflective surface of each digital micromirror unit is perpendicular to the second light beam, that is, whether the reflected light beam of the second light beam returns along the original path; if the reflected light beam does not return along the original path, continue to adjust the driving voltage applied to the second digital micromirror array until the reflected light rays of each digital micromirror unit return along the original path;

[0107] Fix the driving voltage distribution on each digital micromirror unit in the first digital micromirror array and the second digital micromirror array.

[0108] S4. After the first light beam and the second light beam interfere in the beam splitter, an interference light beam including M×M interference light field units is incident on the detector system, and an interference image array is obtained, thereby obtaining the spectral information of the parallel light beam.

[0109] Place the beam reducing system in the outgoing light path of the digital micromirror array on the horizontal axis and perform central alignment; place the area array detector at the image plane position of the beam reducing system, and adjust the position of the area array detector relative to the beam reducing system so that the interference fringes can be clearly imaged.

[0110] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0111] The above specific embodiments of the present invention do not constitute a limitation to the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A digital micromirror array spectrometer, characterized in that, Including: A light source system, a beam splitting system, a first digital micromirror array, a second digital micromirror array, and a detector system; The light source system is used to emit a parallel light beam and incident it into the beam splitting system; the beam splitting system is used to divide the parallel light beam into a first light beam and a second light beam that are perpendicular to each other; the first light beam and the second light beam respectively form two reflected light beams that are divided into M×M regions and have an optical path difference between adjacent regions after being reflected by the first digital micromirror array and the second digital micromirror array; the two reflected light beams return to the beam splitting system again for beam combination and interference, and then form an interference light beam including M×M interference light field units and incident it into the detector system to obtain an interference image array and further obtain the spectral information of the parallel light beam.

2. The digital micromirror array spectrometer according to claim 1, wherein The light source system includes: a light source and a collimating mirror; the light source is used to emit a divergent light beam, and the divergent light beam is collimated by the collimating mirror to obtain the parallel light beam.

3. The digital micromirror array spectrometer according to claim 2, wherein The first digital micromirror array or the second digital micromirror array includes: M×M digital micromirror substrates, M×M digital micromirror units, M×M digital micromirror unit rotation axes, and a driving power supply; The digital micromirror substrate supports the digital micromirror unit; there is a rotational connection between the digital micromirror substrate and the digital micromirror unit rotation axis; the digital micromirror unit rotation axis is fixedly connected to the digital micromirror unit, and the driving power supply is used to provide a driving force for the rotation of the digital micromirror unit, and drives the digital micromirror unit to rotate by driving the rotation of the digital micromirror unit rotation axis.

4. The digital micromirror array spectrometer according to claim 3, characterized in that, The detector system includes: a beam reducing system and a area array detector; The interference light beam including M×M interference light field units is incident into the area array detector after being reduced by the beam reducing system, and the area array detector is used to convert the interference light beam into an electrical signal to obtain an interference image array.

5. The digital micromirror array spectrometer according to claim 4, wherein The angle between the first digital micromirror array and the horizontal plane is set as θ, and the angle between the digital micromirror unit in the first digital micromirror array and the first digital micromirror array is set as θ, so that the first light beam is perpendicular to the digital micromirror unit; thereby reflecting the reflected light of the first light beam into the beam splitting system; The angle between the second digital micromirror array and the horizontal plane is set as φ, and the angle between the digital micromirror unit in the second digital micromirror array and the second digital micromirror array is set as φ, so that the second light beam is perpendicular to the digital micromirror unit; thereby reflecting the reflected light of the second light beam into the beam splitting system; The beam splitting system is a beam splitter; the angle between the beam splitter and the horizontal plane is 45°.

6. The digital micromirror array spectrometer according to claim 5, wherein In the interference light beam composed of M×M interference light field units, the optical path difference δ corresponding to the (i, j)th interference light field unit is: The light-transmitting aperture of the digital micromirror unit in the first digital micromirror array becomes ; The light-transmitting aperture of the digital micromirror cells in the second digital micromirror array becomes ; The size of each interference light field unit is ; where i = 0, 1…M; j = 0, 1…M; a is the width of the digital micromirror unit in the first digital micromirror array; b is the width of the digital micromirror unit in the second digital micromirror array.

7. The digital micromirror array spectrometer according to claim 6, wherein when the optical path difference sequence between adjacent regions in the M×M regions of the interference beam is continuous, the first digital micromirror array and the second digital micromirror array achieve mutual compensation of the optical path to satisfy the following conditions: ， ； or , .

8. A measurement method of the digital micromirror array spectrometer according to any one of claims 1-7, characterized in that, comprising the following steps: S1. The light source system emits a parallel light beam that is incident on the beam splitter and is divided into a first light beam and a second light beam; S2. The first light beam is incident on the first digital micromirror array after being reflected by the beam splitter; the second light beam is incident on the second digital micromirror array after being transmitted by the beam splitter; S3. Adjust the pitch angle and rotation angle of the first digital micromirror array and the second digital micromirror array respectively until the first light beam and the second light beam return to the beam splitter again after being reflected by the first digital micromirror array and the second digital micromirror array; S4. The first light beam and the second light beam interfere in the beam splitter to form an interference beam including M×M interference light field units, which is incident on the detector system to obtain an interference image array and further obtain the spectral information of the parallel light beam.

9. The method for measuring a digital micromirror array spectrometer according to claim 8, wherein The adjustment process of the first digital micromirror array and the second digital micromirror array in step S3 is as follows: By observing whether the first digital micromirror array and the second digital micromirror array are mirror-symmetrical with respect to the beam splitter and whether interference fringes are generated in the area array detector; Until the first digital micromirror array and the second digital micromirror array are mirror-symmetrical with respect to the beam splitter and stable interference fringes are generated in the area array detector, the adjustment process ends.

10. The method for measuring a digital micromirror array spectrometer according to claim 9, characterized in that, By applying driving voltages to the first digital micromirror array and the second digital micromirror array to rotate the digital micromirror units to a preset angle, the driving voltage distributions on the digital micromirror units in the first digital micromirror array and the second digital micromirror array are fixed.

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