CN108120504B - Interference spectrometer based on optical switch array and fabrication method thereof - Google Patents

Abstract

An interference spectrometer based on an optical switch array and a manufacturing method thereof, relate to the technical field of infrared spectrum detection and infrared spectrum analysis, and solve the problems of large volume and heavy weight caused by the use of a high-precision moving mirror drive system in a traditional time-modulated Fourier transform infrared spectrometer. There is also a problem of high cost caused by the use of a cooled infrared area array detector in a spatially modulated Fourier transform infrared spectrometer. , optical switch array, focusing mirror and point detector. The invention uses two stepped phase mirrors to perform distributed phase modulation on the two orthogonal coherent light fields separated by the beam splitter respectively, and uses an optical switch array and a point detector to perform amplitude modulation on the interference light field to achieve stepwise Spectrometer for gating and detection. The invention reduces the cost and has the advantages of miniaturization, light weight, low cost, good portability and the like.

Description

Interference spectrometer based on optical switch array and fabrication method thereof

technical field

The invention relates to an infrared interference spectrometer in the technical field of infrared spectrum detection and infrared spectrum analysis, in particular to an interference spectrometer based on an optical switch array and a manufacturing method.

Background technique

Infrared interference spectroscopy is a science and technology that has made great breakthroughs and has developed rapidly in the past half century. It has the advantages of high sensitivity, accurate wavenumber, and good repeatability. According to the intensity, position and shape of the absorption peaks in the infrared spectrum of the unknown, it is possible to determine which groups are contained in the molecule of the unknown, and then infer the structural composition of the unknown. Fourier transform infrared spectrometer is a kind of infrared interference spectrometer. It has obvious application advantages due to its advantages of multi-channel, high throughput, high precision and low stray light. Fourier transform infrared spectrometers, which are widely studied at present, are divided into time modulation type and spatial modulation type. The time modulation type adopts a moving mirror scanning structure. The high-precision moving mirror drive system increases the size and weight of the instrument. certain restrictions. The spatial modulation type uses a cooled infrared area array detector. The price of the cooled infrared area array detector is very expensive, which limits its application field. In recent years, with the emergence and development of some high-tech fields of science and technology, such as scientific research and engineering applications in the fields of resource exploration, environmental monitoring, meteorological monitoring, life science, etc., for miniaturized, lightweight, cost-effective, portable Infrared spectroscopic instruments for detection and online analysis have put forward a very urgent demand for use.

SUMMARY OF THE INVENTION

The invention solves the problems of large volume and heavy weight caused by the use of a high-precision moving mirror drive system in the traditional time-modulated Fourier transform infrared spectrometer, and solves the problem that the space-modulated Fourier transform infrared spectrometer adopts a cooling-type infrared area array. To solve the problem of high cost caused by the detector, an interference spectrometer based on an optical switch array and a fabrication method are proposed.

An interferometric spectrometer based on an optical switch array, including a light source, a collimating mirror, a beam splitter, a transverse stepped phase mirror, a longitudinal stepped phase mirror, an optical switch array, a focusing mirror and a point detector, and the light emitted by the light source passes through the collimating mirror Then it becomes a parallel beam, the beam reflected by the beam splitter is incident on the lateral stepped phase mirror, and the beam transmitted by the beam splitter is incident on the vertical stepped phase mirror, and the lateral stepped phase mirror and The longitudinal stepped phase mirrors respectively perform spatially distributed phase modulation on the incident light beams, and then interfere with the beam splitter again to form an interference light field array; the interference light field array is incident on the optical switch array, and the optical switch array Each optical switch unit in the interferometric light field array performs step-by-step reception for each interference light field unit in the interferometric light field array, and is converged on the point detector by the focusing mirror to obtain the interference light intensity sampling sequence;

The lateral stepped phase mirror and the longitudinal stepped phase mirror divide the incident light field into a plurality of light field units, and each light field unit corresponds to one row of the lateral stepped phase mirror and one row of the vertical stepped phase mirror. One column mirror unit; each row mirror unit on the horizontal stepped phase mirror corresponds to one phase modulation amount, and each column mirror unit on the vertical stepped phase mirror corresponds to another phase modulation amount. When the light field reflected by the longitudinal stepped phase mirror interferes, the interference light field corresponding to each row mirror unit on the transverse stepped phase mirror and each column mirror unit on the longitudinal stepped phase mirror has a phase difference, and the outgoing light has a phase difference. The field is an interference light field array with spatial phase difference distribution, and each interference light field unit corresponds to a different phase difference;

The outgoing interference light field array is incident on the optical switch array, and each optical switch unit in the optical switch array corresponds to an interference light field unit in the interference light field array. When a certain optical switch unit on the optical switch array is in an open state , the interference light field unit corresponding to the optical switch unit in the interference light field array passes through, and is received by the point detector through the focusing mirror.

A fabrication method of an interference spectrometer based on an optical switch array, the method is realized by the following steps:

The method of making an interference spectrometer based on an optical switch array adopts the method of combining visible laser array calibration and infrared camera observation to integrate the system. It is characterized in that the method is realized by the following steps:

Step 1. Use a visible laser array to calibrate the optical axis of the system. The laser array has the same number of rows M as the horizontal stepped phase mirror and the same number of columns N as the vertical stepped phase mirror, and the spacing of each laser unit in the laser array in the lateral direction is equal to the longitudinal direction. The unit width b of the stepped phase mirror, the spacing in the longitudinal direction is equal to the unit width a of the lateral stepped phase mirror, and by adjusting the position and angle of the laser array source, each optical axis of the laser array is made parallel;

Step 2. Insert a 45° visible light beam splitting prism into the optical path, the visible light beam splitting prism divides the laser array beam into two paths, and by adjusting the position and angle of the beam splitting prism, the transmitted laser beam and the laser array beam are collinear and reflected. The laser beam is perpendicular to the laser array beam;

Step 3: Place the lateral stepped phase mirror 4 in the optical path of the reflective laser array, and adjust the position and angle of the lateral stepped phase mirror so that each row of laser beams in the optical path of the reflected laser array is incident on each row of the lateral stepped phase mirror for reflection. On the center line of the long axis of the mirror unit, and the light beam incident on the lateral stepped phase mirror returns along the original path, so that the lateral stepped phase mirror is perpendicular to the optical axis of the laser array;

The longitudinal stepped phase mirror is placed in the optical path of the transmission laser array. By adjusting the position and angle of the longitudinal stepped phase mirror, each column of laser beams in the optical path of the transmitted laser array is incident on each column of the longitudinal stepped phase mirror. On the center line of the long axis of the unit, and the light beam incident on the longitudinal stepped phase mirror returns along the original path, so that the longitudinal stepped phase mirror and the optical axis of the laser array are collinear;

Step 4: Rotate the visible light beam splitting prism by 90°, turn the reflected laser beam to 180°, place the optical switch array in the optical path of the rotated reflected laser beam, and adjust the position and angle of the optical switch array to make the incident light into the optical switch array. Each laser beam on the optical switch array is located at the center of each optical switch unit of the optical switch array;

Step 5. Remove the visible light beam splitting prism, and place the beam splitter at the position of the visible light beam splitter prism; by adjusting the position and angle of the beam splitter, each laser beam reflected on the lateral stepped phase mirror is located at the position of each row of mirror units. On the midline of the long axis, and the beam reflected by the lateral stepped phase mirror returns along the original path;

Step 6. Place the collimating mirror in the front optical path, adjust the position and angle of the collimating mirror, so that the laser array is symmetrically distributed on the surface of the collimating mirror, and the laser beam reflected by the surface of the collimating mirror is on the laser array. The source plane is also distributed in opposite directions to ensure the level of the optical axis of the collimating mirror;

Step 7: Remove the laser array, place the infrared light source in front of the collimating mirror, and adjust the position of the infrared light source so that the infrared light source is located at the object focus of the collimating mirror;

Step 8: Place the infrared camera behind the optical switch array, turn on the infrared light source, set all the optical switch units of the optical switch array to the open state, and adjust the position of the infrared camera so that one of the two stepped phase mirrors is in the infrared The image is clearly imaged on the area array detector of the camera, and then the axial translation position of the other stepped phase mirror is adjusted, and the infrared camera is used to observe until the interference image appears;

Step 9. Remove the infrared camera, place the focusing mirror behind the optical switch array, and place the infrared area array detector on the focal plane of the image side of the focusing mirror. The beams in the open state are all focused on the center of the infrared area array detector;

Step 10. Remove the infrared area array detector, place the point detector on the focal plane of the focusing mirror, adjust the position of the point detector, and fix each device when the output signal of the point detector is maximized to complete the system integration.

Beneficial effects of the present invention: The interference spectrometer based on the optical switch array described in the present invention is a kind of distributed phase modulation using two stepped phase mirrors respectively to the two coherent light fields separated by the beam splitter, and A spectroscopic instrument that uses optical switch arrays and point detectors to perform amplitude modulation on interfering light fields to realize step-by-step gating and detection. Compared with the time-modulated Fourier transform infrared spectrometer, this instrument has no high-precision moving mirror drive system. The optical switch array can be detected by a point detector, which not only further reduces the volume and weight, but also greatly reduces the cost. Therefore, this tiny infrared interference spectrometer has the advantages of miniaturization, light weight, low cost, and good portability. It has important application value in the field of infrared spectroscopy detection and infrared spectroscopy analysis.

Description of drawings

1 is a schematic structural diagram of an optical switch array-based interference spectrometer according to the present invention;

2 is a schematic diagram of the mirror position of the lateral stepped phase mirror and the vertical stepped phase mirror relative to the beam splitter and the distributed phase difference distribution formed by the modulation of the optical field in the optical switch array-based interference spectrometer according to the present invention;

3 is a schematic diagram of gating of an optical field unit in an interference optical field array by an optical switch array in an optical switch array-based interference spectrometer according to the present invention;

4 is a schematic diagram of stepwise gating of the optical switch array to the interference light field array in the optical switch array-based interference spectrometer according to the present invention;

FIG. 5 is a schematic diagram of matching the diffraction spot and the photosensitive surface of the detector in the interference spectrometer based on the optical switch array according to the present invention;

6 is a front view of the diffraction spot matching the photosensitive surface of the detector in the optical switch array-based interference spectrometer according to the present invention;

7 is a view of the grid beam splitter in the optical switch array-based interference spectrometer according to the present invention;

Figure 8 is a schematic diagram of the horizontal and vertical grid edge structures of ten grid beam splitters, of which the left part is Figure 8a, Figure 8c, Figure 8e, Figure 8g, Figure 8i, Figure 8k, Figure 8m, Figure 8o, Figure 8q and Figure 8s are front cross-sectional views of ten grid beam splitters; Figures 8b, 8d, 8f, 8h, 8j, 8l, 8n, 8p, 8r, and 8t of the right part are the left side sectional views corresponding to the front sectional views, respectively;

9a to 9f in FIG. 9 are schematic diagrams of cross-sectional shapes of double-sided grid ridges;

Figure 10 is a top view of the grid beam splitter structure;

Figure 11 is a schematic diagram of the horizontal and vertical grid ridge structures of ten grid beam splitters, of which the left part is Figure 11a, Figure 11c, Figure 11e, Figure 11g, Figure 11i, Figure 11k, Figure 11m, Figure 11o, Figure 11q and Fig. 11s are front cross-sectional views of ten grid beam splitters; Fig. 11b, Fig. 11d, Fig. 11f, Fig. 11h, Fig. 11j, Fig. 11l, Fig. 11n, Fig. 11p, Fig. 11r and Fig. 11t of the right part are the left side sectional views corresponding to the front sectional views, respectively;

12 is a schematic diagram of the preparation process of the grid thin film beam splitter;

Figure 13 is a schematic diagram of the preparation process of the grid strip thin film beam splitter;

14 is a schematic structural diagram of a stepped phase mirror with a stepped structure formed by multiple layer deposition methods;

15 is a schematic structural diagram of a stepped phase mirror with a stepped structure formed by multiple etching methods;

16 is a schematic structural diagram of a stepped phase mirror with a stepped structure formed by a mixed method of etching first and then coating;

17 is a schematic structural diagram of a stepped phase mirror with a stepped structure formed by a cutting method;

18a to 18g in FIG. 18 are schematic diagrams of the fabrication sequence of the optical switch array-based interference spectrometer according to the present invention, respectively.

Detailed ways

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the present embodiment will be described with reference to FIG. 1 to FIG. 17 . An interferometric spectrometer based on an optical switch array includes a light source 1 , a collimating mirror 2 , a beam splitter 3 , a transverse stepped phase mirror 4 , a longitudinal stepped phase mirror 5 , an optical switch array 6 , a focusing mirror 7 and a point detector 8 .

The light source 1 is located on the focal plane of the object side of the collimating mirror 2. The divergent beam emitted by the light source 1 becomes a parallel beam after passing through the collimating mirror 2. The beam splitter 3 is located in the parallel beam and divides it into two coherent beams of equal intensity. Light. The transverse stepped phase mirror 4 and the longitudinal stepped phase mirror 5 are respectively located at the exit pupil positions of the collimating mirrors in the two vertical optical paths reflected and transmitted by the beam splitter, and are in mirror positions relative to the beam splitter 3 .

The light field reflected by the beam splitter 3 is incident on the transverse stepped phase mirror 4 , and the light field transmitted by the beam splitter 3 is incident on the longitudinal stepped phase mirror 5 . The stepped arrangement of the lateral stepped phase mirror 4 and the vertical stepped phase mirror 5 is orthogonal to the mirror image of the beam splitter 3, thereby dividing the incident light field into a plurality of localized light field units, and each light field unit corresponds to There is a row mirror unit on the lateral stepped phase mirror 4 and a column mirror unit on the vertical stepped phase mirror 5 .

The lateral stepped phase mirror 4 introduces a longitudinally distributed phase modulation amount to the incident light field, and the longitudinal stepped phase mirror 5 introduces a laterally distributed phase modulation amount to the incident light field.

The light field modulated and reflected by the transverse stepped phase mirror 4 and the light field modulated and reflected by the longitudinal stepped phase mirror 5 meet again through the beam splitter 3 and interfere. Since each row mirror unit on the lateral stepped phase mirror 4 corresponds to a phase modulation amount, and each column mirror unit on the vertical stepped phase mirror 5 corresponds to a phase modulation amount, when the lateral stepped phase mirror 4 and the longitudinal When the light field reflected by the stepped phase mirror 5 interferes, the interference light field corresponding to each row mirror unit on the lateral stepped phase mirror 4 and each column mirror unit on the vertical stepped phase mirror 5 has a phase difference value. . Therefore, the outgoing light field is an interference light field array with spatial phase difference distribution, and each interference light field unit corresponds to a phase difference value.

The interferometric optical field array modulated by the two stepped phase mirrors is incident on the optical switch array 6 . In order to satisfy the Fourier transform relationship between the light field emitted by the optical switch array 6 and the light field detected by the point detector 8, the optical switch array 6 is located on the object-side focal plane of the focusing mirror 7, and the point detector 8 is located at the focus on the image-side focal plane of mirror 7. Each optical switch unit in the optical switch array 6 corresponds to one interference light field unit in the interference light field array. When an optical switch unit on the optical switch array 6 is in an open state, the interference light field unit corresponding to this optical switch unit is allowed to pass through, and is received by the spot detector 8 through the focusing mirror 7 . In this way, each optical switch unit on the optical switch array 6 is sequentially opened and closed according to the spatial phase difference arrangement sequence, so that each interference optical field unit in the interference optical field array passes through the optical switch array 6 in the sequence of the phase difference. , and are collected by the focusing mirror 7 on the point detector 8 and received sequentially, thereby obtaining the interference light intensity sampling sequence.

The opening and closing sequence of each optical switch unit in the optical switch array 6 described in this embodiment needs to be the same as the arrangement sequence of the phase difference formed by the two stepped phase mirrors, that is, the addressing of the optical switch unit is the same as that of the two stepped phase mirrors. The phase difference distribution formed by the mirrors is strictly matched, and the on-off of the corresponding interference light field unit is controlled by controlling the opening and closing of each optical switch unit, so as to realize the sequential gating of the interference light field array. Control the opening and closing of the corresponding optical switch units on the optical switch array in turn according to the spatial distribution order of the phase difference in the interference light field array, so that each interference light field unit in the interference light field array passes through the optical switch array in the order of the phase difference, and Condensed by the focusing mirror 7 to the spot detector 8 and sequentially received.

The horizontal stepped phase mirror 4 and the vertical stepped phase mirror 5 in this embodiment are located at mirror positions relative to the beam splitter 3 , and a certain row of mirror units of the horizontal stepped phase mirror 4 and the vertical stepped phase mirror 5 A certain column of mirror elements of the mirror overlap. The transverse stepped phase mirror 4 and the longitudinal stepped phase mirror 5 are both composed of a plurality of mirror units, each mirror unit corresponds to a thickness value, and the mirror units with different thicknesses are sequentially arranged in a stepped structure.

Specifically, with reference to FIG. 2 , for the lateral stepped phase mirror 4, taking the 0th row mirror unit 4-1 in the stepped phase mirror as a reference, it is assumed that the lateral stepped phase mirror 4 has M row mirror units, The width of each row mirror unit is a, and the thickness of the first row mirror unit 4-2 relative to the 0th row mirror unit 4-1 is h, then the thickness of the remaining row mirror units along the longitudinal direction is h is the step size increasing sequentially. In order to achieve effective sampling of the interferogram, the thickness h of the mirror unit is required to be h≤λ/4.

Set the wave number of the incident light as ν, then the phase modulation introduced by the first row mirror unit 4-2 to the light field incident on it is 4πνh, and the M-1th row mirror unit pair is incident on it. The phase modulation introduced by the light field is 4πν(M-1)h. Therefore, the phase modulation of the light field by the transverse stepped phase mirror 4 can be expressed as

In the formula, (x, y) is the coordinate point, j is an imaginary number, and rect() is a rectangular function; for the longitudinal stepped phase mirror 5, the 0th column mirror unit 5-1 in the stepped phase mirror is used as the benchmark. , it is assumed that the stepped phase mirror 5 has N column mirror units, and the width of each column mirror unit is b, then the first column mirror unit 5-2 is relative to the 0th column mirror unit 5-1 The thickness of the mirror unit is Mh, and the thickness of the remaining columns of mirror units increases in the order of Mh in the lateral direction. Therefore, the phase modulation amount introduced by the first column mirror unit to the light field incident thereon is 4πνMh, and the phase modulation amount introduced by the N-1th column mirror unit to the light field incident thereon is 4πν (N-1)Mh. The phase modulation of the light field by the longitudinal stepped phase mirror 5 can be expressed as

纵向阶梯相位反射镜的第0个列反射镜单元与横向阶梯相位反射镜的第M-3个行反射镜单元所对应的干涉光场单元的相位差为

纵向阶梯相位反射镜5的第0个列反射镜单元与横向阶梯相位反射镜的第0个行反射镜单元所对应的干涉光场单元的相位差为

纵向阶梯相位反射镜5的第1个列反射镜单元与横向阶梯相位反射镜的第M-1个行反射镜单元所对应的干涉光场单元的相位差为

纵向阶梯相位反射镜的第1个列反射镜单元与横向阶梯相位反射镜的第M-2个行反射镜单元所对应的干涉光场单元的相位差为依次类推，纵向阶梯相位反射镜的第n个列反射镜单元与横向阶梯相位反射镜的第m个行反射镜单元所对应的干涉光场单元的相位差为

由此形成空间分布的相位差阵列9。A certain row of mirror units of the transverse stepped phase mirror 4 and a certain column of mirror units of the longitudinal stepped phase mirror 5 are mirrored with respect to the beam splitter 3, thereby introducing spatial phase difference distribution to the interference light field. When the mirror unit 5-1 of the 0th column of the longitudinal stepped phase mirror 5 and the mirror unit 4-3 of the M-1th row of the horizontal stepped phase mirror 4 are coincident with the mirror images of the beam splitter, The phase difference of the corresponding interference light field unit is 0, so the interferometric light field unit corresponding to the 0th column mirror unit of the longitudinal stepped phase mirror and the M-2th row mirror unit of the transverse stepped phase mirror The phase difference is

The phase difference of the interference light field unit corresponding to the 0th column mirror unit of the longitudinal stepped phase mirror and the M-3 row mirror unit of the horizontal stepped phase mirror is:

The phase difference of the interference light field unit corresponding to the 0th column mirror unit of the longitudinal stepped phase mirror 5 and the 0th row mirror unit of the transverse stepped phase mirror is:

The phase difference of the interference light field unit corresponding to the first column mirror unit of the vertical stepped phase mirror 5 and the M-1 row mirror unit of the horizontal stepped phase mirror is:

The phase difference of the interference light field unit corresponding to the first column mirror unit of the longitudinal stepped phase mirror and the M-2 row mirror unit of the horizontal stepped phase mirror is: By analogy, the phase difference of the interference light field unit corresponding to the n-th column mirror unit of the longitudinal stepped phase mirror and the m-th row mirror unit of the lateral stepped phase mirror is:

A spatially distributed phase difference array 9 is thus formed.

依次类推，纵向阶梯相位反射镜5的第n个列反射镜单元与横向阶梯相位反射镜4的第m个行反射镜单元所对应的干涉光场单元的相位差为

When the n _0th column mirror unit of the longitudinal stepped phase mirror 5 and the m _0th row mirror unit of the transverse stepped phase mirror 4 are mirror images of the beam splitter 3, then (m ₀ , n ₀ ) the phase difference of the interfering light field units is 0, the interference light corresponding to the n _0th column mirror unit of the longitudinal stepped phase mirror 5 and the m ₀ -1 row mirror unit of the transverse stepped phase mirror 4 The phase difference of the field unit is The phase difference of the interference light field unit corresponding to the n _0th column mirror unit of the longitudinal stepped phase mirror and the m ₀ +1 row mirror unit of the transverse stepped phase mirror 4 is:

By analogy, the phase difference of the interference light field unit corresponding to the n-th column mirror unit of the longitudinal stepped phase mirror 5 and the m-th row mirror unit of the lateral stepped phase mirror 4 is:

By controlling the mirror images of the different mirror units of the transverse stepped phase mirror 4 and the longitudinal stepped phase mirror 5 relative to the beam splitter 4 to overlap, different methods such as unilateral sampling, bilateral sampling and small bilateral sampling of the interference light intensity can be realized. sampling method.

The optical switch array 6 described in this embodiment is located in the interferometric light field array modulated by the stepped phase mirror, and forms an angle of 45° with the beam splitter. In order to satisfy the Fourier transform relationship between the light field emitted by the optical switch array 6 and the light field detected by the point detector 8 to achieve optimal reception, the optical switch array 6 is located on the object-side focal plane of the focusing mirror 7, and the point detection The detector 8 is located on the image-side focal plane of the focusing mirror 7 .

The optical switch array 6 can be implemented by using a liquid crystal spatial light modulator. The specific implementation method is that the liquid crystal spatial light modulator is divided into a number of liquid crystal spatial light modulation units, and each liquid crystal spatial light modulation unit is used as an optical switch unit. Each interference light field unit corresponds to each other, and the amplitude modulation of the interference light field array is realized by controlling the transmittance and opacity of each liquid crystal spatial light modulation unit.

3, the optical switch array 6 is composed of a plurality of optical switch units distributed in a two-dimensional space. By controlling the opening and closing of the optical switch unit 6-1, the interferometric optical field array 10 and the optical switch unit 6-1 can be realized. Passing and blocking of the interference light field unit 10-1 corresponding to 1. In order to realize the effective gating of the optical switch array 6 to the interference light field array 10 , each optical switch unit in the optical switch array 6 needs to be matched with each interference light field unit of the interference light field array.

It is assumed that the transverse stepped phase mirror 4 has M row mirror units, and the width of each row mirror unit is a, and the longitudinal stepped phase mirror 5 has N column mirror units, and the width of each column mirror unit is b. Set the size of each optical switch unit of the optical switch array 6 as s×t and the number as K×L, then the size of each optical switch unit in the optical switch array 6 should satisfy the relationship s≤a, t≤b , and the number of optical switch arrays should satisfy the relationship K≥M, L≥N. The amplitude modulation effect of the optical switch array 6 on the light field can be expressed as

The optical switch array 6 described in this embodiment performs stepwise gating on the interference light field array according to the distribution order of the phase difference, that is to say, the addressing of the optical switch array is in one-to-one correspondence with the spatial distribution of the phase difference;

4, when the interference light field array is incident on the optical switch array, it is assumed that the (m,n)th optical switch unit 6-1 in the optical switch array is in the "on" state, while the rest of the optical switch units are in the "on" state. "off" state, then the "on" state of the (m,n)th optical switch unit 6-1 transmits the (m,n)th interference light field unit 10-1 of the interference light field array through the focusing mirror 7 It converges to the point detector 8 for detection, and the "off" state of the remaining optical switch units blocks the remaining interfering light field units. At the next moment, the (m+1,n)th optical switch unit 6-2 in the optical switch array is in the "on" state, and the rest of the optical switch units are in the "off" state, then the (m+1,n)th optical switch unit is in the "off" state. The "on" state of the optical switch unit 6-2 transmits the (m+1,n)th interference light field unit 10-2 of the interference light field array and converges on the point detector 8 through the focusing mirror 7 for detection, The "off" state of the remaining optical switch units blocks the remaining interfering light field units. As a result, the interferometric light field array modulated by the stepped phase mirror, with the sequential opening and closing of the optical switch array, the interferometric light field units with different phase differences are received by the point detector at different times, so as to obtain the interference light intensity sampling sequence .

The function of the focusing mirror 7 in this embodiment is to focus the interference light field unit gated by a certain optical switch unit of the optical switch array onto the point detector 8 for collection. The focusing mirror works in the infrared band and is made of infrared optical materials such as silicon, germanium, zinc selenide, and zinc sulfide. In order to realize the effective convergence of the focusing mirror 7 on all the interfering light field units, the aperture of the focusing mirror 7 needs to match the aperture of the stepped phase mirror and the optical switch array, that is, the aperture Φ of the focusing mirror 7 should satisfy the relationship

The present embodiment will be described with reference to FIG. 5 and FIG. 6 . The point detector 8 described in this embodiment is located at the focal point of the focusing mirror 7 on the image side, and performs energy collection for each interference light field unit. The point detector 8 uses indium antimonide (InSb) or mercury cadmium telluride (HgCdTe) material. Set the focal length of the focusing mirror 7 to be f, the size of the photosensitive surface of the point detector 8 to be c×d, and the wavelength of the light wave to be λ. The intensity of the interference light on the surface is a diffraction spot 11, and the lateral and vertical dimensions of the diffraction spot are 2λf/s and 2λf/t, respectively. In order to suppress the overflow of light energy from the detector, it is necessary to focus the light energy of the diffraction spot 11 into the photosensitive surface of the point detector 8 . Therefore, the size of the photosensitive surface of the detector 8 must be larger than the size of the diffraction spot 11 of the interference light intensity;

The size of the photosensitive surface of the detector should satisfy the relation

In this embodiment, the beam splitter 3 can adopt a parallel plate structure in the infrared band, and is composed of a beam splitter plate and a compensation plate. The beam splitter plate is made of zinc selenide (ZnSe), potassium bromide (KBr) or cesium iodide (CsI). ) and other infrared optical materials as the base material, or use undoped semiconductor materials such as silicon (Si), germanium (Ge) and gallium arsenide (GaAs) as the base material; the compensation plate uses the same base material as the beam splitter . The flatness of the two surfaces of the beam splitter and the compensation plate is required to be ≤λ/20, the surface roughness is required to be ≤3nm, and λ is the wavelength. For high refractive index substrates, the first surface does not need to be coated with a beam splitter, only the second surface needs to be coated with an anti-reflection coating. For low-index substrates, it is only necessary to deposit a broadband beamsplitter film on the first surface of the substrate with a reflectivity close to 0.5. For substrates with intermediate refractive indices, both beam splitter coatings and anti-reflection coatings are required. When a high refractive index silicon material is used as the substrate of the semiconductor beam splitter, the silicon substrate material corresponds to a refractive index of 3.4, and the coating material can be selected from germanium, polyethylene or polypropylene. The difference in reflectivity of light intensity in different polarization directions can be reduced by reducing the incident angle of the beam on the beam splitter. If the beam splitter and the compensation plate are placed at 45° to the optical axis, the dimensions of the beam splitter and the compensation plate are

The beam splitter can also be a light beam splitter with a grid structure, and the grid beam splitter uses a grid structure to support the beam splitting film. Since the beam-splitting film is too thin to be self-supporting, a grid structure is used to support the beam-splitting film. The grid structure adopts semiconductor material, and the beam splitting film adopts polyester film. The grid structure needs to match the structure of the stepped phase mirror. The grid thin film beam splitter is placed at 45° to the optical axis of the system. According to the geometric parameters of the stepped phase mirror, the size of each grid period of the grid thin film beam splitter is

倍，分束窗3-2在横向的宽度是其纵向宽度的倍，分束窗3-2在横向和纵向具有相同的占空比。由于分束窗的尺寸决定了系统的光通量，因此分束窗3-2的面积远远大于栅棱3-1的面积。每个分束窗3-2在横向阶梯相位反射镜4和纵向阶梯相位反射镜5上的投影位于各个反射镜单元上，而每条栅棱3-1在横向阶梯相位反射镜4和纵向阶梯相位反射镜5上的投影位于相邻反射镜单元的交界位置。7 and 8, the grid structure of the grid thin film beam splitter is composed of grid ridges 3-1 and beam splitting windows 3-2, and the width of the grid ridge in the transverse direction is equal to its longitudinal width.

times, the width of the beam splitting window 3-2 in the horizontal direction is the width of its vertical width times, the beam splitting window 3-2 has the same duty cycle in the horizontal and vertical directions. Since the size of the beam splitting window determines the luminous flux of the system, the area of the beam splitting window 3-2 is much larger than the area of the grid edge 3-1. The projection of each beam splitting window 3-2 on the lateral stepped phase mirror 4 and the longitudinal stepped phase mirror 5 is located on each mirror unit, and each grating edge 3-1 is on the lateral stepped phase mirror 4 and the longitudinal stepped phase mirror 5. The projection on the phase mirror 5 is located at the junction of adjacent mirror units.

The number of grids in two different directions of the grid beam splitter is P and Q respectively, P=Q or P≠Q; P corresponds to the M direction of the stepped phase mirror, and M and P have a multiple relationship; Q corresponds to the N direction of the stepped phase mirror, and N and Q have a multiple relationship.

The grid period in the P direction is a'+b', a' is the width of a single edge in the P direction, and b' is the width of a single beam splitting window in the P direction. where a'2=a'3=...=a'P; a'1 and a'(P+1) can be the same as other grid edges or different; b'1=b'2=...=b'P . The total length of the grid beam splitter in the P direction: Lp=a'1+b'1+a'2+b'2+...+a'P+b'P+a'(P+1).

The grid period in the Q direction is c'+d', c' is the width of a single edge in the Q direction, and d' is the width of a single beam splitting window in the Q direction. Where c'2=c'3=...=c'q; c'1 and c'(Q+1) can be the same as other grid edges or different; d'1=d'2=...=d'Q . The total length of the grid beam splitter in the Q direction: LQ=c'1+d'1+c'2+d'2+...+c'Q+d'Q+c'(Q+1).

Grid beam splitter edge width a', c' range is 1nm-100cm, beam splitter window width b', d' range is 1nm-100cm; grid beam splitter edge thickness range is 1nm-100cm, beam splitter window The thickness range is 1nm-100cm. The compensation plate can be selected or not added according to the specific parameters. The structure and material of the compensation plate can be the same as that of the beam splitter, or it can be different.

The ten shapes of the grid beam splitter in Fig. 8, the beam splitting window and grid edge of the grid beam splitter are homogeneous structure or heterostructure, Fig. 8a, 8b, Fig. 8e, 8f, Fig. 8i, 8j, Figures 8m, 8n, 8q, 8r have a homogeneous structure or a heterostructure of the beam splitter window and grid edge; Figures 8c, 8d, 8g, 8h, 8k, 8l, 8o, 8p, 8s, 8t, The beam splitting window and the grid edge are of a homogeneous structure. In the grid beam splitter structure, the cross section of the grid rib structure can be rectangular (Figure 8i, Figure 8k, Figure 8m, Figure 8o), parallelogram (Figure 8a, Figure 8c, Figure 8e, Figure 8g), trapezoid (Figure 8q) , Figure 8s), arc or other shapes. In the same grid beam splitter, the grid edges in the horizontal direction and the grid edges in the vertical direction can be of the same structure or different.

Referring to Figure 9, in the grid beam splitter structure, the cross section of the grid rib structure can also be a double-sided rectangle (Figure 9a, Figure 9b), a double-sided parallelogram (Figure 9c, Figure 9d), a double-sided trapezoid (Figure 9e, Figure 9f) or other shapes.

This embodiment is described with reference to FIG. 10 . FIG. 10 is a plan view of a structural scheme of a grid beam splitter, 3-1 is a grid edge, and 3-2 is a beam splitting window. The grid number of the grid beam splitter is Q, Q corresponds to the N direction of the stepped phase mirror, and N and Q have a multiple relationship. The grid period in the Q direction is c'+d', c' is the width of a single edge in the Q direction, and d' is the width of a single beam splitting window in the Q direction. Where c'2=c'3=...=c'Q; c'1 and c'(Q+1) can be the same as other grid edges or different; d'1=d'2=...=d'Q . The total length of the grid beam splitter in the Q direction: LQ=c'1+d'1+c'2+d'2+...+c'Q+d'Q+c'(Q+1).

The grid beam splitter edge width c' ranges from 1nm-100cm, and the beam splitter window width d' ranges from 1nm to 100cm; the grid beam splitter edge thickness ranges from 1nm to 100cm, and the beam splitter window thickness ranges from 1nm to 100cm. . The compensation plate can be selected or not added according to the specific parameters. The structure and material of the compensation plate can be the same as that of the beam splitter, or it can be different.

The beam splitting window of the grid beam splitter is the same as the grid edge and grid beam splitter, and can be a homogeneous structure or a heterogeneous structure. In the grid beam splitter structure, the cross section of the grid rib structure can also be rectangular, parallelogram, trapezoid or other shapes. In the same grid beam splitter, the grid edges in the horizontal direction and the grid edges in the vertical direction can be of the same structure or different.

FIG. 11 is a schematic diagram of the horizontal and vertical grid rib structures of ten kinds of grid beam splitters. In the grid beam splitter structure, the cross section of the grid rib structure may also be a double-sided rectangle, a double-sided parallelogram, a double-sided trapezoid or other shapes.

In this embodiment, the grid rib material in the grid beam splitter and the grid beam splitter can be selected from metal, non-metal inorganic material or organic material, or can be a mixed material of several properties. Such as aluminum, copper, titanium, nickel, gold and other metals, aluminum oxide, ceramics, quartz, glass, calcium fluoride, zinc selenide, zinc sulfide, silicon, germanium, silicon dioxide, silicon nitride and other non-metallic materials and Supporting organic materials. The beam splitting window material can be quartz, glass, calcium fluoride, magnesium fluoride, barium fluoride, lithium fluoride, zinc selenide, zinc sulfide, silicon, germanium, silicon dioxide, silicon nitride, polyimide, PMMA, aluminum, beryllium, non-metallic inorganic or organic materials. The refractive materials, reflective materials, and absorbing materials ranging from X-rays to far-infrared wavelengths, or even wider wavelength ranges, which are not proposed in this embodiment, can be applied to the device.

The present embodiment will be described with reference to FIG. 12 , which shows the process of fabricating the grid thin film beam splitter; first, the grid structure is fabricated. The grid structure is fabricated by the micro-optical electromechanical system (MOEMS) process. Specifically, as shown in Figure 12, undoped semiconductor materials such as silicon (Si), germanium (Ge) and gallium arsenide (GaAs) are selected as the substrate. A layer of photoresist is spin-coated on the semiconductor base material, as shown in Figure 12a, and then exposed and developed with a grid pattern mask to remove the photoresist at the position of the beam splitting window to expose the surface of the semiconductor substrate, as shown in Figure 12b. Then, wet etching or dry etching technology is used to remove the semiconductor base material at the position of the beam splitting window to form a hollow structure, as shown in Figure 12c. Finally, the photoresist at the position of the gate edge is removed to form a grid structure, as shown in Figure 12d. The beam-splitting window material is fixed on the grid structure, the beam-splitting window is supported by the grid edges, and the beam-splitting window is used to achieve beam splitting, and finally the grid-membrane beam splitter is completed, as shown in Figure 12e.

When the beam splitting film used is relatively thick, a grid thin film beam splitter can be used, and the grid thin film beam splitter uses a grid structure to support the beam splitting film. The grid structure adopts semiconductor material, and the beam splitting film adopts polyester film. The grid structure needs to match the structure of the lateral stepped phase mirror. The grid thin film beam splitter is placed at 45° to the optical axis of the system. According to the geometric parameters of the stepped phase mirror, the size of each strip period of the grid thin film beam splitter is

This embodiment is described with reference to FIG. 13 . FIG. 13 is a schematic diagram of the process of making a grid-bar film beam splitter. Since the size of the beam-splitting window determines the luminous flux of the system, the width of the beam-splitting window is much larger than that of the grid edge. The projection of each beam splitting window on the lateral stepped phase mirror 4 is located on each mirror unit, and the projection of each grating edge on the lateral stepped phase mirror 4 is located at the junction of adjacent mirror units.

For the grid thin film beam splitter, the grid structure is firstly fabricated. The grid structure is fabricated by a micro-optical electromechanical system (MOEMS) process. Undoped semiconductor materials such as silicon (Si), germanium (Ge), and gallium arsenide (GaAs) are selected as the substrate. layer photoresist, as shown in Figure 13a, and then place a mask with a grid pattern on the substrate on which the photoresist has been spin-coated, and remove the photoresist at the position of the beam splitting window through exposure and development to expose The surface of the semiconductor substrate at the location of the beam splitting window is shown in Figure 13b. Then, wet etching or dry etching technology is used to remove the semiconductor base material at the position of the beam splitting window to form a hollow structure, as shown in FIG. 13c. Finally, the photoresist at the gate edge position is removed to form a gate stripe structure, as shown in FIG. 13d. The polyester film is fixed on the grid structure, the grid edges are used to support the polyester film, and the beam splitting window is used to realize the beam splitting of the polyester film, and finally the production of the grid film beam splitter is completed, as shown in Figure 13e.

In this embodiment, the manufacturing method of the grid beam splitter can be divided into an integrated manufacturing method and a separate manufacturing method. One-piece production method 1: ultra-precision machining method. It is realized by cutting, grinding, polishing and other technologies on the integrated material; manufacturing method 2: using the MEMS technology manufacturing method. Methods such as photolithography, dry etching, wet etching, etc. are performed on the integrated material. For example, the anisotropic etching method of single crystal material, the RIE etching method, the ICP etching and surface polishing modification method, etc., as well as the manufacturing method combining the related MEMS methods.

Example 1: The grid beam splitter shown in FIG. 8s was fabricated, and the material was a double-sided polished (100) single crystal silicon wafer with high flatness and high parallelism. Its preparation method is:

1. Grow or evaporate silicon dioxide and silicon nitride and other dielectric films or composite films on the cleaned double-sided polished single crystal silicon surface as a masking film;

2. Orientation photolithography, revealing the side groove pattern, removing the masking film in the side groove pattern by etching, exposing the surface of single crystal silicon. Single-crystal silicon anisotropic etching solution is used to etch the side groove, and the etching depth is equal to the final thickness of the beam splitting window; the shape of the side groove can also be formed by a plurality of rectangles or squares arranged at a certain distance in addition to the figure.

3. Perform a second photolithography to expose the beam splitting window pattern, and remove the masking film in the beam splitting window pattern by etching to expose the surface of the single crystal silicon. The photoresist is removed, and the side groove and the beam splitting window are simultaneously etched with a single crystal silicon anisotropic etching solution, and the etch depth is etched until the side groove is etched to a thickness of 0, and the beam splitting window reaches the final thickness at this time.

4. Remove the masking film, evaporate the beam splitter film, and complete the device preparation.

Example 2: For the double-sided grid-rib beam splitter with both the horizontal and vertical grid-rib structures as shown in Figure 9f, the above method can be used to manufacture the beam splitter. The difference is that a double-sided masking film needs to be prepared. It is realized by corrosion, and the upper and lower surface patterns are the same. During the first photolithography etching, the sum of the etching depths of the upper and lower surface edge grooves is the final thickness value of the beam splitting window.

Example 3: The grid beam splitter is fabricated as shown in Figure 8k, and the material is a double-sided polished silicon wafer with high flatness and high parallelism. Its production process is as follows:

1. Evaporate aluminum film or thermally grown silicon dioxide or vapor-deposit silicon nitride and other metal films or dielectric films or composite films on the surface of the cleaned double-sided polished single crystal silicon as a masking film;

2. Photolithography, exposing the side groove pattern, removing the masking film in the side groove pattern by etching, exposing the surface of the single crystal silicon. Using ICP or RIE technology side grooves, the corrosion depth is equal to the final thickness of the beam splitting window; the shape of the side grooves can also be composed of multiple rectangles, squares, circles, ellipses or other polygonal shapes, arranged at a certain distance. to make.

3. Perform a second photolithography to expose the beam splitting window pattern, and remove the masking film in the beam splitting window pattern by etching to expose the surface of the single crystal silicon. Remove the photoresist, and use ICP or RIE technology to etch the side groove and the beam splitter window at the same time.

4. Remove the masking film, evaporate the beam splitter film, and complete the device preparation.

Example 4:

For the double-sided grid-rib beam splitter with both the horizontal and vertical grid-rib structures as shown in Figure 9b, the above-mentioned method can be used to prepare the beam splitter. , the upper and lower surfaces are the same. During the first photolithography and etching, the sum of the etching depths of the upper and lower surface side grooves is the final thickness value of the beam splitting window.

Example 5:

The structure is a grid beam splitter made in the shape of Figure 8o, and the material is a double-sided polished (110) single crystal silicon wafer with high flatness and high parallelism. The manufacturing process is similar to that of Example 1.

Example 6:

For the double-sided grid beam splitter whose structure is corresponding to the shape of the grid beam splitter as shown in Figure 8o, the material is the same as that of Example 5, and its manufacturing method is similar to that of Example 5. The difference is that it is necessary to prepare double-sided beam splitters. The masking film is realized by double-sided photolithography and double-sided etching, and the upper and lower surface patterns are the same. During the first photolithography and etching, the sum of the etching depths of the upper and lower surface side grooves is the final thickness value of the beam splitting window.

The grid and grid beam splitter of other materials or structures can also be realized by the above methods, and can also be realized by wet etching and dry etching of MEMS and alternating between the two methods. The conventional single crystal material with the required angle is used as the substrate, and the structure with the dip angle can be etched; the structure with the dip angle can also be etched by the tilt rotation method; the compensation pattern can also be designed so that the obtained The structure is more precise.

In this embodiment, the following three methods can also be selected: 1. The beam-splitting window and the grid edge can be selected to be of the same or different materials, and the grid-rib structure can be prepared on the surface of the beam-splitting window with a supporting material or without a supporting material. , The grid edge structure can be realized by MEMS technology, such as X-ray lithography, deep ultraviolet lithography, evaporation and lithography, as well as peeling, electroforming and other processes . Using the flexibility of X-ray lithography and other technologies, through the control of the beam angle, grid-rib structures of various structural forms can be realized. After the grid rib is fabricated, for the substrate with the beam splitting window support structure, the support structure needs to be removed. Coating beam splitter film to complete the beam splitter production.

2. Select the same or different materials for the beam-splitting window and the grid edge, bond the beam-splitting window structure and the grid-rib structure material together, and then use ultra-precision machining or MEMS technology to form the grid-rib structure, and then remove the beam-splitting window Adhesive to the surface, and beam splitting window support. Coating beam splitter film to complete the beam splitter production.

3. The beam-splitting window and the grid edge can be selected to be the same material or different materials, and the beam-splitting window structure and the grid-edge structure can be fabricated separately by ultra-precision machining or MEMS technology, and then they are bonded together by bonding or other connection methods. .

This embodiment will be described with reference to FIG. 14. In this embodiment, the lateral stepped phase mirror 4 and the vertical stepped phase mirror 5 are made of glass, quartz (SiO ₂ ), silicon (Si), germanium (Ge), gallium arsenide ( On the substrate of materials such as GaAs), a stepped structure is formed by multiple layer deposition methods. First, the substrate of glass, quartz (SiO ₂ ), silicon (Si), germanium (Ge), gallium arsenide (GaAs) and other materials A layer of photoresist was spin-coated as shown in Figure 14a. By masking, exposing and developing, half of the substrate width of the photoresist was removed to expose the half substrate width of the substrate surface, as shown in Figure 14b, and then electron beam evaporation was used Or magnetron sputtering and other coating processes to evaporate a film with a certain thickness, as shown in Figure 14c, and then remove the photoresist and film on the mask part to form a two-step structure, as shown in Figure 14d. Next, the step structure is glued, masked, exposed and developed again, and the surface of half the width of the step is exposed on each step, as shown in Figure 14e, and then a coating process such as electron beam evaporation or magnetron sputtering is used again. A film is deposited with a thickness that is half the thickness of the previous coating, as shown in Figure 14f. Finally, the photoresist and the film layer of the mask part are removed to form a four-step structure, as shown in Figure 14g. By repeating this process, each time the width of the mask is half the width of the previous mask, and each time the thickness of the film layer is half the thickness of the previous film, the required stepped phase mirror structure can be obtained.

This implementation is described with reference to FIG. 15. The stepped phase mirror can be formed on a substrate of semiconductor materials such as silicon (Si), germanium (Ge), and gallium arsenide (GaAs) by multiple etchings to form a stepped structure; (Si), germanium (Ge), and gallium arsenide (GaAs) and other semiconductor materials are spin-coated with a layer of photoresist, as shown in Figure 15a, by masking, exposing and developing, the photoresist half the width of the substrate is removed , expose the substrate surface of half the width of the substrate, and then use wet etching or dry etching process to etch the exposed substrate surface to a certain depth, and then remove the photoresist in the mask part to form a two-step structure, As shown in Figure 15b. Next, glue, mask, expose and develop the substrate with the two-step structure again, and expose the substrate surface with half the width of the step on each step, as shown in Figure 15c, and then use wet etching or dry etching again. The exposed substrate surface is etched to a depth of half the etch depth of the previous etch, and finally the photoresist on the mask portion is removed to form a four-step structure, as shown in Figure 15d. By repeating this process, each time the width of the mask is half the width of the previous mask, and each time the etching depth is half of the previous etching depth, the required stepped phase mirror structure can be obtained.

This embodiment is described with reference to FIG. 16. The stepped phase mirror can be formed on a substrate of semiconductor materials such as silicon (Si), germanium (Ge), and gallium arsenide (GaAs) by a mixed method of etching and then coating to form a stepped structure; first A layer of photoresist is spin-coated on the substrate of semiconductor materials such as silicon (Si), germanium (Ge) and gallium arsenide (GaAs), as shown in Figure 16a, through masking, exposure and development, half the width of the substrate is removed. The photoresist is used to expose the substrate surface of half the substrate width, and then the exposed substrate surface is etched to a certain depth by wet etching or dry etching process, and then the photoresist in the mask part is removed to form two steps structure, as shown in Figure 16b. Next, the step structure is subjected to gluing, masking, exposure and development again, and the surface of half the step width is exposed on each step, as shown in Figure 16c, and then a coating process such as electron beam evaporation or magnetron sputtering is used to carry out The film layer is deposited, and the thickness of the film layer is half of the depth of the previous etching. Finally, the photoresist and the film layer in the mask part are removed to form a four-step structure, as shown in Figure 15d. In the actual operation process, by first circulating the etching process to form a certain number of steps, and then recycling the coating process, the required stepped phase mirror structure can finally be obtained.

This embodiment is described with reference to FIG. 17. The stepped phase mirror can use metal materials such as aluminum (Al) and copper (Cu) as the substrate, and form a stepped structure by cutting. The substrate is polished, as shown in Fig. 17a, and then the shaded portion in Fig. 17b is cut with a mechanical tool. After cleaning and polishing, two step structures are formed, as shown in Fig. 17c. Continue to use a mechanical tool to cut the shaded part in Figure 17d, after cleaning and polishing, three step structures are formed, as shown in Figure 17e. The shaded part in Fig. 17f is cut again with a mechanical tool, and after cleaning and polishing, four step structures are formed, as shown in Fig. 17g. By repeating this process, the required stepped phase mirror structure can be obtained.

After the stepped phase mirror structure is fabricated, a reflective film layer of high-reflectivity materials such as gold (Au) and aluminum (Al) is evaporated on the surface of the stepped structure to finally form a stepped phase mirror; the plane of each mirror unit of the stepped phase mirror Degree requirements ≤ λ/20, surface roughness requirements ≤ 3nm.

Embodiment 2. This embodiment is described with reference to FIG. 18 . This embodiment is the preparation method of the optical switch array-based interference spectrometer described in Embodiment 1:

The system is integrated by the method of combining visible laser array calibration and infrared camera observation. The specific production process is:

(1) Use a visible laser array to calibrate the optical axis of the system. The laser array has the same number of rows M as the horizontal stepped phase mirror and the same number of columns N as the vertical stepped phase mirror, and the spacing of each laser unit in the laser array in the lateral direction is equal to the longitudinal direction. The unit width b of the stepped phase mirror is equal to the unit width a of the horizontal stepped phase mirror. By adjusting the position and angle of the laser array source, each optical axis of the laser array is made parallel; the visible laser array calibration system In order to integrate and arrange a plurality of visible lasers into an array for packaging, so that they can emit multiple parallel laser beams, it is used as the adjustment auxiliary calibration system of the present invention.

(2) Insert a 45° visible light beam splitting prism into the optical path. The visible light beam splitting prism divides the laser array beam into two paths. By adjusting the position and angle of the beam splitting prism, the transmitted laser beam and the laser array beam are collinear and reflected. The laser beam is perpendicular to the laser array beam;

(3) The lateral stepped phase mirror 4 is placed in the optical path of the reflective laser array, and by adjusting the position and angle of the lateral stepped phase mirror, each row of laser beams in the optical path of the reflected laser array is incident on each row of the lateral stepped phase mirror for reflection. On the center line of the long axis of the mirror unit, and the light beam incident on the lateral stepped phase mirror returns along the original path, so that the lateral stepped phase mirror is perpendicular to the optical axis of the laser array;

(4) The longitudinal stepped phase mirror 5 is placed in the optical path of the transmission laser array, and by adjusting the position and angle of the longitudinal stepped phase mirror, each column of laser beams in the optical path of the transmission laser array is incident on the optical path of the longitudinal stepped phase mirror. The long axis centerline of each column of mirror units, and the light beam incident on the longitudinal stepped phase mirror returns along the original path, so that the longitudinal stepped phase mirror and the optical axis of the laser array are collinear, as shown in Figure 18a;

(5) Rotate the visible light beam splitting prism by 90°, turn the reflected laser beam to 180°, place the optical switch array 6 in the optical path of the rotated reflected laser beam, and adjust the position and angle of the optical switch array to make the incident light on the optical switch Each laser beam on the array is located at the center of each optical switch unit of the optical switch array as shown in Figure 18b;

(6) Remove the visible light beam splitter and place the parallel plate beam splitter, grid film beam splitter or grid film beam splitter at the position of the visible beam beam splitter; due to the flat plate beam splitter, grid film beam splitter or The grid thin film beam splitter works in the infrared band, and only reflects and does not transmit to the visible laser array. Therefore, the reflective optical path is used to adjust the flat beam splitter, the grid thin film beam splitter or the grid thin film beam splitter. For the parallel-plate beam splitter, by adjusting the position and angle of the parallel-plate beam splitter, the laser beams reflected on the lateral stepped phase mirrors are located on the center line of the long axis of each row of mirror units, and are blocked by the lateral stepped phase mirrors. The reflected beam returns along the same path. For the grid thin film beam splitter, by adjusting the position and angle of the grid thin film beam splitter, each laser beam of the laser array is incident on the center position of each beam splitting window of the grid thin film beam splitter, and at the same time, it is reflected to the transverse direction. The light beam on the stepped phase mirror is located on the center line of the long axis of each row of mirror units, and the light beam reflected by the lateral stepped phase mirror returns along the original path. For the grid thin film beam splitter, by adjusting the position and angle of the grid thin film beam splitter, the laser beams of each row of the laser array are incident on the centerline of the long axis of each beam splitting window of the grid thin film beam splitter, and the reflected The light beams on the lateral stepped phase mirrors are located on the center line of the long axis of each row of mirror units, and the beams reflected by the lateral stepped phase mirrors return along the original path, as shown in Figure 18c.

(7) The collimating mirror is placed in the front optical path. Since the collimating mirror transmits infrared and reflects visible light, using this feature, the laser array is symmetrically distributed on the surface of the collimating mirror by adjusting the position and angle of the collimating mirror. , and the laser beams reflected by the surface of the collimating mirror are also distributed on the plane of the laser array source, so as to ensure the level of the optical axis of the collimating mirror, as shown in Figure 18d.

(8) Remove the laser array, place the infrared light source in front of the collimating mirror, and adjust the position of the infrared light source so that the infrared light source is located at the object focus of the collimating mirror.

(9) Place the infrared camera behind the optical switch array, turn on the infrared light source, and set all optical switch units of the optical switch array to the "on" state. Adjust the position of the infrared camera so that one of the two stepped phase mirrors can be clearly imaged on the area detector of the infrared camera. Then adjust the axial translation position of another stepped phase mirror and observe with an infrared camera until an interference image appears, as shown in Figure 18e.

(10) Remove the infrared camera, place the focusing mirror behind the optical switch array, and place the infrared area array detector on the focal plane of the image side of the focusing mirror. By adjusting the position and angle of the focusing mirror, each optical switch unit The beams in the "on" state are all focused on the center of the infrared area array detector, as shown in Figure 18f.

(11) Remove the infrared area array detector, place the single-point detector on the focal plane of the focusing mirror, and adjust the position of the single-point detector so that when the output signal of the detector is the largest, fix each device to complete the system. Integrated production, as shown in Figure 18g.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. As long as the function is not changed, on the basis of the above description, the basic elements of the optical switch array-based interference spectrometer can be changed or changed in other forms without exceeding the scope of the present disclosure. be exhausted. And the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (9)

1. The interference spectrometer based on the optical switch array comprises a collimating mirror (2), a beam splitter (3), a transverse step phase reflector (4), a longitudinal step phase reflector (5), an optical switch array (6), a focusing mirror (7) and a point detector (8), wherein a light beam emitted by a light source (1) is emitted to form a parallel light beam after passing through the collimating mirror (2), the parallel light beam is reflected by the beam splitter (3) and then enters the transverse step phase reflector (4), the light beam transmitted by the beam splitter enters the longitudinal step phase reflector (5), and the transverse step phase reflector (4) and the longitudinal step phase reflector (5) respectively perform spatial distributed phase modulation on the incident light beam and then interfere with the incident light beam through the beam splitter (3) again to form an interference light field array; the interference light field array is incident on the optical switch array (6), each optical switch unit in the optical switch array (6) receives each interference light field unit in the interference light field array in a stepping mode, and the interference light field units are converged on a point detector (8) through a focusing mirror (7), so that an interference light intensity sampling sequence is obtained; it is characterized in that;

the transverse step phase reflector (4) and the longitudinal step phase reflector (5) divide an incident light field into a plurality of light field units, and each light field units correspond to row reflector units of the transverse step phase reflector (4) and column reflector units of the longitudinal step phase reflector (5), each row reflector unit on the transverse step phase reflector (4) corresponds to phase modulation amounts, each column reflector unit on the longitudinal step phase reflector (5) corresponds to another phase modulation amounts, when the transverse step phase reflector (4) interferes with the light field reflected by the longitudinal step phase reflector (5), the interference light field corresponding to each row reflector unit on the transverse step phase reflector (4) and each column reflector unit on the longitudinal step phase reflector (5) has phase difference, an emergent light field is a light field interference light field with spatial phase difference distribution, and each interference array unit corresponds to different phase differences;

the emergent interference light field array is incident on a light switch array (6), each light switch unit in the light switch array (6) corresponds to interference light field units in the interference light field array, when light switch units on the light switch array (6) are in an open circuit state, an incident light field and the interference light field unit corresponding to the light switch unit pass through, and are received by a point detector (8) through a focusing mirror (7);

setting a transverse step phase reflector (4) to have M row reflector units, the width of each row reflector unit is a, setting a longitudinal step phase reflector (5) to have N column reflector units, the width of each column reflector unit is b, the size of each optical switch unit in an optical switch array (6) is s multiplied by t, the number of the optical switch arrays (6) is K multiplied by L, each optical switch unit of the optical switch array (6) corresponds to each interference light field unit of the interference light field array, setting the size of each optical switch unit in the optical switch array (6) to satisfy the relation that s is less than or equal to a, t is less than or equal to b, and the array number of the optical switch array (6) to satisfy K is greater than or equal to M, and L is greater than or equal to N;

setting the wavelength of light waves of an incident light field to be lambda, the size of a point detector (8) to be c multiplied by d, the size of a diffuse spot on the point detector (8) to be 2 lambda f/s multiplied by 2 lambda f/t, and the size of a photosensitive surface of the point detector (8) to meet the requirement

f is the focal length of the focusing mirror (7);

the beam splitter (3) is a light beam splitter with a grid edge structure and comprises grid edges, beam splitting windows and beam splitting films, the grid edges divide the beam splitter spatially to form a beam splitting window array, the beam splitting films are positioned on the upper surfaces of the beam splitting windows or the upper surfaces of the beam splitting windows and the grid edges, and the grid edges support the beam splitting films;

the width of the grid edges in the grid beam splitter in the transverse direction being that of the grid edges in the longitudinal direction

The width of the beam-splitting window in the transverse direction being greater than that in the longitudinal direction

The duty ratios of the beam splitting windows in the transverse direction and the longitudinal direction are the same;

the width range of the grid edge in the grid mesh beam splitter is 1nm-100cm, and the width range of the beam splitting window is 1nm-100 cm; the thickness range of the grid edges is 1nm-100cm, and the thickness range of the beam splitting window is 1nm-100 cm;

the cross section structure of the grid edges in the grid mesh beam splitter is a single-sided rectangle, a single-sided parallelogram, a single-sided trapezoid, a double-sided rectangle, a double-sided parallelogram or a double-sided trapezoid;

the manufacturing method of the interference spectrometer based on the optical switch array adopts a method of combining visible laser array calibration and infrared camera observation to carry out system integration, and is characterized by comprising the following steps:

, calibrating the system optical axis by using a visible laser array, wherein the laser array has the same row number M as the transverse step phase reflector and the same column number N as the longitudinal step phase reflector, the horizontal distance of each laser unit of the laser array is equal to the unit width b of the longitudinal step phase reflector, the vertical distance of each laser unit of the laser array is equal to the unit width a of the transverse step phase reflector, and the optical axes of the laser array are parallel by adjusting the position and the angle of a laser array source;

inserting pieces of 45-degree visible light splitting prisms into a light path, wherein the visible light splitting prisms divide the laser array light beam into two paths, the positions and the angles of the splitting prisms are adjusted to enable the transmitted laser beam to be collinear with the laser array light beam, and the reflected laser beam to be perpendicular to the laser array light beam;

placing a transverse step phase reflector (4) in a light path of a reflection laser array, and enabling each row of laser beams in the light path of the reflection laser array to be incident on the central line of a long axis of each row of reflector units of the transverse step phase reflector by adjusting the position and the angle of the transverse step phase reflector, and enabling the light beams incident on the transverse step phase reflector to return along the original path, so that the transverse step phase reflector is vertical to the optical axis of the laser array;

a longitudinal step phase reflector (5) is placed in a light path of a transmission laser array, each row of laser beams in the light path of the transmission laser array are made to be incident on the central line of a long axis of each row of reflector units of the longitudinal step phase reflector by adjusting the position and the angle of the longitudinal step phase reflector, and the light beams incident on the longitudinal step phase reflector return along the original path, so that the optical axis of the longitudinal step phase reflector and the optical axis of the laser array are collinear;

rotating the visible light beam splitter prism by 90 degrees, turning the reflected laser beams by 180 degrees, placing the optical switch array (6) in the optical path of the rotated reflected laser beams, and enabling each laser beam incident on the optical switch array to be positioned at the central position of each optical switch unit of the optical switch array by adjusting the position and the angle of the optical switch array;

removing the visible light splitting prism, and placing the beam splitter at the position of the visible light splitting prism; by adjusting the position and the angle of the beam splitter, each laser beam reflected to the transverse step phase reflector is positioned on the central line of the long axis of each row of reflector units, and the light beam reflected by the transverse step phase reflector returns along the original path;

placing the collimating mirror (2) in a front light path, and adjusting the position and the angle of the collimating mirror to ensure that the laser array is symmetrically distributed on the surface of the collimating mirror, and laser beams reflected by the surface of the collimating mirror are also distributed in an opposite array on a laser array source plane, so that the optical axis of the collimating mirror is ensured to be horizontal;

removing the laser array, placing the infrared light source in front of the collimating mirror (1), and enabling the infrared light source to be located on an object focus of the collimating mirror by adjusting the position of the infrared light source;

placing the infrared camera on the optical switch array (6), turning on an infrared light source, setting all optical switch units of the optical switch array to be in an on state, adjusting the position of the infrared camera to enable of the two step phase reflectors to clearly image on an area array detector of the infrared camera, then adjusting the axial translation positions of the other step phase reflectors, and observing by adopting the infrared camera until an interference image appears;

removing the infrared camera, placing the focusing mirror (7) behind the optical switch array (6), placing the infrared area array detector on an image focal plane of the focusing mirror (7), and enabling the light beams in the on states of the optical switch unit to be focused on the central position of the infrared area array detector by adjusting the position and the angle of the focusing mirror (7);

and step ten, removing the infrared area array detector, placing the point detector (8) on a focal plane of the focusing mirror (7), adjusting the position of the point detector (8), and fixing each device when the output signal of the point detector is maximum to complete system integration.

2. The optical switch array based interference spectrometer of claim 1, wherein; the beam splitter is manufactured by adopting an ultra-precise machining method and an MOEMS technology;

the preparation method comprises cutting, grinding and polishing on a substrate to obtain grid edges and beam splitting windows, and evaporating beam splitting film to complete device preparation;

the preparation of the beam splitter by adopting the MOEMS technology is realized by the following steps:

, selecting monocrystalline silicon as a substrate, and preparing a masking film on the surface of the monocrystalline silicon;

step two, directional photoetching is carried out, the masking film in the side groove graph is removed through an etching method, and the side groove graph is exposed; etching the side groove by using the monocrystalline silicon anisotropic etching solution, wherein the etching depth of the side groove is equal to the final thickness of the beam splitting window;

step three, carrying out second photoetching, removing the masking film in the beam splitting window graph through etching, and exposing the beam splitting window graph; adopting monocrystalline silicon anisotropic etching liquid to etch the side groove and the beam splitting window simultaneously, wherein the etching depth is up to the etching thickness of the side groove being 0, and the beam splitting window reaches the final thickness;

and step four, removing the masking film on the surface of the grid edge, and integrally evaporating the beam splitting film to finish the preparation of the beam splitter.

3. The optical switch array based interference spectrometer of claim 1, wherein;

the phase modulation formula of the transverse step phase reflector (4) and the longitudinal step phase reflector (5) to the light field is as follows:

the amplitude modulation formula of the optical switch array (6) to the incident light field is as follows:

and each optical switch unit on the optical switch array (6) is sequentially opened and closed according to a spatial phase difference arrangement sequence, so that each interference optical field unit in the interference optical field array sequentially passes through the optical switch array (6) according to the phase difference sequence and is converged on a point detector (8) by a focusing mirror (7) to be sequentially received, and an interference light intensity sampling sequence is obtained.

4. The optical switch array based interference spectrometer of claim 1, wherein;

the transverse step phase reflector (4) and the longitudinal step phase reflector (5) are both composed of a plurality of reflector units, the flatness of each reflector unit is less than or equal to lambda/20, the surface roughness is less than or equal to 3nm, the thickness h of each reflector unit is less than or equal to lambda/4, each reflector units correspond to thickness values, the reflector units with different thicknesses are sequentially arranged into a step structure, the step thickness increment of each reflector unit in the transverse step phase reflector (4) is h, and the step thickness increment of each reflector unit of the longitudinal step phase reflector (5) is Mh.

5. The optical switch array based interference spectrometer of claim 1, wherein; setting the wave number of the optical wave as v, when the nth step phase reflector (5) is used₀M-th of column mirror unit and transverse step phase mirror₀When the row mirror units are overlapped in a mirror image mode relative to the beam splitter (3), the phase difference between the nth row mirror unit of the longitudinal step phase mirror and the (m, n) th interference light field unit corresponding to the mth row mirror unit of the transverse step phase mirror is 4 pi v (nM-m-n)₀M+m₀)h。

6. The optical switch array based interference spectrometer of claim 1, wherein only optical switch cells are on at a particular time in the optical switch array , and the remaining optical switch cells are off.

7. The optical switch array-based interference spectrometer of claim 1, wherein the on state of the (m, n) th optical switch cell in the optical switch array transmits the (m, n) th interference optical field cell corresponding to the m-th row mirror cell of the transverse step phase mirror and the n-th column mirror cell of the longitudinal step phase mirror, and the off state of the rest of the optical switch cells blocks the rest of the interference optical field cells.

8. The optical switch array based interference spectrometer of claim 1, wherein the aperture of the focusing mirror (7) matches the apertures of the step phase reflector and the optical switch array, i.e. the aperture Φ of the focusing mirror (7) satisfies

9. The method for manufacturing an interference spectrometer based on an optical switch array according to claim 1, wherein the system integration is performed by a method combining visible laser array calibration and infrared camera observation, and the method is implemented by the following steps:

, calibrating the system optical axis by using a visible laser array, wherein the laser array has the same row number M as the transverse step phase reflector and the same column number N as the longitudinal step phase reflector, the horizontal distance of each laser unit of the laser array is equal to the unit width b of the longitudinal step phase reflector, the vertical distance of each laser unit of the laser array is equal to the unit width a of the transverse step phase reflector, and the optical axes of the laser array are parallel by adjusting the position and the angle of a laser array source;

inserting pieces of 45-degree visible light splitting prisms into a light path, wherein the visible light splitting prisms divide the laser array light beam into two paths, the positions and the angles of the splitting prisms are adjusted to enable the transmitted laser beam to be collinear with the laser array light beam, and the reflected laser beam to be perpendicular to the laser array light beam;

placing a transverse step phase reflector (4) in a light path of a reflection laser array, and enabling each row of laser beams in the light path of the reflection laser array to be incident on the central line of a long axis of each row of reflector units of the transverse step phase reflector by adjusting the position and the angle of the transverse step phase reflector, and enabling the light beams incident on the transverse step phase reflector to return along the original path, so that the transverse step phase reflector is vertical to the optical axis of the laser array;

a longitudinal step phase reflector (5) is placed in a light path of a transmission laser array, each row of laser beams in the light path of the transmission laser array are made to be incident on the central line of a long axis of each row of reflector units of the longitudinal step phase reflector by adjusting the position and the angle of the longitudinal step phase reflector, and the light beams incident on the longitudinal step phase reflector return along the original path, so that the optical axis of the longitudinal step phase reflector and the optical axis of the laser array are collinear;

rotating the visible light beam splitter prism by 90 degrees, turning the reflected laser beams by 180 degrees, placing the optical switch array (6) in the optical path of the rotated reflected laser beams, and enabling each laser beam incident on the optical switch array to be positioned at the central position of each optical switch unit of the optical switch array by adjusting the position and the angle of the optical switch array;

removing the visible light splitting prism, and placing the beam splitter at the position of the visible light splitting prism; by adjusting the position and the angle of the beam splitter, each laser beam reflected to the transverse step phase reflector is positioned on the central line of the long axis of each row of reflector units, and the light beam reflected by the transverse step phase reflector returns along the original path;

placing the collimating mirror (2) in a front light path, and adjusting the position and the angle of the collimating mirror to ensure that the laser array is symmetrically distributed on the surface of the collimating mirror, and laser beams reflected by the surface of the collimating mirror are also distributed in an opposite array on a laser array source plane, so that the optical axis of the collimating mirror is ensured to be horizontal;

removing the laser array, placing the infrared light source in front of the collimating mirror (1), and enabling the infrared light source to be located on an object focus of the collimating mirror by adjusting the position of the infrared light source;

placing the infrared camera on the optical switch array (6), turning on an infrared light source, setting all optical switch units of the optical switch array to be in an on state, adjusting the position of the infrared camera to enable of the two step phase reflectors to clearly image on an area array detector of the infrared camera, then adjusting the axial translation positions of the other step phase reflectors, and observing by adopting the infrared camera until an interference image appears;

removing the infrared camera, placing the focusing mirror (7) behind the optical switch array (6), placing the infrared area array detector on an image focal plane of the focusing mirror (7), and enabling the light beams in the on states of the optical switch unit to be focused on the central position of the infrared area array detector by adjusting the position and the angle of the focusing mirror (7);

and step ten, removing the infrared area array detector, placing the point detector (8) on a focal plane of the focusing mirror (7), adjusting the position of the point detector (8), and fixing each device when the output signal of the point detector is maximum to complete system integration.

Images