Liquid crystal spectrometer and measurement method thereof

Abstract

The present invention provides a liquid crystal spectrometer and a measurement method thereof, wherein the spectrometer includes: a light source system, a beam splitter, a liquid crystal compensation device, a liquid crystal phase reflector, and a detector system; the light source system is used to emit a linearly polarized light beam incident on the beam splitter, which is then split into a transmitted light beam and a reflected light beam by the beam splitter. The reflected light beam is incident on the liquid crystal compensation device, reflected, and then returned to the beam splitter; the transmitted light beam is incident on the liquid crystal phase reflector, reflected, and has a preset optical path difference. It returns to the beam splitter and interferes with the reflected light beam to form an interference light beam that is incident on the detector system, thereby obtaining an interference light signal and acquiring spectral information of the linearly polarized light beam. The present invention avoids the moving mirror scanning mechanism of traditional Fourier transform spectrometers, improves the stability and reliability of the system, and reduces the volume and weight of the system. The liquid crystal spectrometer structure proposed in this invention has the characteristics of miniaturization, staticity, high stability, and high environmental adaptability.

Description

Technical Field

[0001] The present invention relates to the field of spectral technology, and in particular to a liquid crystal spectrometer and a measurement method thereof. Background Art

[0002] Spectroscopic technology can obtain information about the composition and content of target substances. It has been increasingly applied in fields such as physical experiments, chemical analysis, biological characterization, medical testing, and ecological and environmental protection, and has played a vital role in the exploration and discovery of new materials, new energy sources, and the unknown world. To obtain the spectral characteristics of the target, the detected complex light must be spectrally decomposed. Currently, commonly used spectroscopic instruments mainly use filter spectroscopy, prism spectroscopy, grating spectroscopy, and interference spectroscopy. Among them, Fourier transform spectroscopy, which uses interference spectroscopy, 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 scientific and technological fields such as space exploration, aerial remote sensing, Earth surveying, atmospheric monitoring, and military reconnaissance, the specialized applications and environments of these instruments have created an urgent need for miniaturized, static Fourier transform spectrometers. This escalating demand has led to insurmountable technical bottlenecks in conventional Fourier transform spectrometers. Currently, the Fourier transform spectrometers commonly used in laboratories employ a time-modulated interferometer structure, where a moving mirror scans the interferometer to generate an optical path difference to obtain spectral information. These instruments incorporate a high-precision moving mirror scanning mechanism for precise sampling of the interferogram. This mechanism is complex to manufacture, sensitive to vibration, and demanding in its operating environment. Furthermore, the moving mirror scanning mechanism is large and heavy. Furthermore, the use of a beam splitter for light separation results in half the energy loss, reducing system stability and reliability, making it unsuitable for aerospace applications such as meteorological observation and atmospheric remote sensing. This, in turn, limits its application in high-tech fields such as space exploration, meteorological remote sensing, and military reconnaissance. Summary of the Invention

[0004] In light of the above-mentioned issues, the present invention aims to provide a liquid crystal spectrometer and its measurement method. By adjusting the driving voltage applied between the two transparent electrodes of a liquid crystal phase mirror, the tilt angle of the long axis of the nematic liquid crystal molecules in the liquid crystal layer of the liquid crystal phase mirror is adjusted, thereby modulating the refractive index of the liquid crystal material and, in turn, controlling the optical path difference between the two coherent light beams. This eliminates the moving mirror scanning mechanism of a traditional Fourier transform spectrometer, improves the system's stability and reliability, and reduces its size and weight. The liquid crystal spectrometer structure proposed in this invention is characterized by miniaturization, static operation, high stability, and high environmental adaptability.

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

[0006] The present invention provides a liquid crystal spectrometer, comprising: a light source system, a beam splitter, a liquid crystal compensation device, a liquid crystal phase reflector and a detector system;

[0007] The light source system is used to emit a linearly polarized light beam which is incident on the beam splitter and is divided into a transmitted light beam and a reflected light beam by the beam splitter. The reflected light beam is incident on the liquid crystal compensation device and is reflected and then returns to the beam splitter; the transmitted light beam is incident on the liquid crystal phase reflector and is reflected with a preset optical path difference. It returns to the beam splitter and interferes with the reflected light beam to form an interference light beam which is incident on the detector system to obtain an interference light signal and acquire the spectral information of the linearly polarized light beam.

[0008] Preferably, the light source system comprises: a light source, a collimator and a polarizer;

[0009] The light source is used to emit a divergent light beam. The collimator collimates the divergent light beam into a parallel light beam and then the beam is incident on the polarizer. The polarizer converts the parallel light beam into a linearly polarized light beam and then the beam is incident on the beam splitter.

[0010] Preferably, the liquid crystal compensation device comprises: a liquid crystal compensator and a plane reflective mirror;

[0011] The reflected light beam is reflected by the beam splitter and then incident on the plane mirror through the liquid crystal compensator; after being reflected by the plane mirror again, it is incident on the beam splitter through the liquid crystal compensator;

[0012] The liquid crystal compensator is used to compensate the optical path lengths of the transmitted light beam and the reflected light beam separated by the beam splitter.

[0013] Preferably, the liquid crystal phase reflector comprises, from top to bottom, a glass cover, an upper transparent electrode, an upper alignment film, a liquid crystal layer, a lower alignment film, a lower transparent electrode and a glass substrate;

[0014] The glass cover and the glass substrate form a liquid crystal cell structure for fixing the liquid crystal layer; the upper and lower surfaces of the glass cover are coated with anti-reflection films, the upper surface of the glass substrate is evaporated with an anti-reflection film, and the lower surface is evaporated with a high-reflection film;

[0015] The upper transparent electrode and the lower transparent electrode serve together as driving electrodes for the liquid crystal layer;

[0016] The upper and lower alignment films work together to orient the liquid crystal molecules in the liquid crystal layer; the material of the liquid crystal layer is nematic liquid crystal;

[0017] The electrode leads are used to connect the upper transparent electrode and the lower transparent electrode to a voltage driving source respectively.

[0018] Preferably, the voltage driving source provides a voltage difference to the liquid crystal layer, so as to drive the long axis pointing direction of the liquid crystal molecules in the liquid crystal layer to change;

[0019] When different driving voltages V are applied, the liquid crystal molecules in the liquid crystal layer have different long-axis pointing tilt angles θ(V);

[0020] Different liquid crystal molecule long axis pointing tilt angles correspond to different refractive indices; the relationship between the refractive index of extraordinary light and the liquid crystal pointing tilt angle is:

[0021] Among them, n o 、n e are the refractive indices of ordinary light and extraordinary light in the liquid crystal layer when there is no voltage, respectively.

[0022] Preferably, the equivalent refractive index of extraordinary light in the liquid crystal caused by the driving voltage V is Therefore, the optical path of the extraordinary light when it propagates in the liquid crystal is OP(V) = 2n(V)L;

[0023] Wherein, L is the thickness of the liquid crystal layer;

[0024] After the transmitted light beam is reflected by the liquid crystal phase reflector, the phase delay is

[0025] Preferably, the detector system comprises: a focusing mirror and a photodetector;

[0026] The interference light beam is converged by the focusing mirror and incident on the photoelectric detector, which performs photoelectric conversion to realize the collection of the interference light signal.

[0027] Preferably, the driving voltage source adopts a step-by-step scanning method, that is, the refractive index of the liquid crystal layer changes linearly with the same step length Δn, and the refractive index is: n(V)=n e +kΔn;

[0028] Where k = 1, 2, ..., N, N is the number of sampling points;

[0029] At this time, the optical path difference sampling sequence is:

[0030] δ(k)=2kΔnL。

[0031] Preferably, the change step length Δn of the refractive index satisfies the following relationship:

[0032]

[0033] Among them, λ min is the minimum wavelength in a linearly polarized beam.

[0034] The present invention also provides a measurement method of a liquid crystal spectrometer, comprising the following steps:

[0035] S1. The light source system emits a linearly polarized beam which is incident on the beam splitter and is split into an identical reflected beam and a transmitted beam by the beam splitter.

[0036] S2, the transmitted light beam is reflected by the liquid crystal phase reflector and then returns to the beam splitter; the reflected light beam is transmitted by the liquid crystal compensator and reflected by the plane reflector and then returns to the beam splitter. The two light beams interfere at the exit surface of the beam splitter to form an interference beam;

[0037] S3. The interference light beam is incident on the detector system to obtain an interference light signal and acquire the spectral information of the linearly polarized light beam.

[0038] Compared to existing technologies, this invention replaces the scanning mirror of a traditional Fourier transform spectrometer with a liquid crystal phase mirror. By adjusting the drive voltage on the liquid crystal phase mirror, the refractive index of the liquid crystal material is modulated, thereby controlling the optical path length of light traveling through the liquid crystal, achieving precise sampling of the optical path difference. This patent proposes a liquid crystal spectrometer that utilizes voltage scanning instead of the mechanical scanning process of a traditional mirror. This static structure avoids the manufacturing and control difficulties associated with moving parts, improving system stability and reliability while reducing system size and weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a schematic structural diagram of a liquid crystal spectrometer provided according to an embodiment of the present invention.

[0040] Figure 2 Schematic diagram of the structure of a liquid crystal phase reflector in a liquid crystal spectrometer provided according to an embodiment of the present invention.

[0041] Figure 3 Schematic diagram of driving voltage distribution in a liquid crystal spectrometer provided according to an embodiment of the present invention.

[0042] Figure 4 4 is a flow chart of a liquid crystal spectrometer measurement method provided according to an embodiment of the present invention.

[0043] Figure 5 It is a flowchart of a liquid crystal spectrometer measurement method provided according to an embodiment of the present invention.

[0044] The figures include: light source 1, collimator 2, polarizer 3, beam splitter 4, liquid crystal phase reflector 5, voltage driver 6, liquid crystal compensator 7, plane reflector 8, focusing mirror 9, photodetector 10, glass cover 11, upper transparent electrode 12, upper orientation film 13, liquid crystal layer 14, lower orientation film 15, lower transparent electrode 16, glass substrate 17, electrode leads 18 and liquid crystal molecules 19. DETAILED DESCRIPTION

[0045] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical modules are denoted by identical reference numerals. In the case of identical reference numerals, their names and functions are also identical. Therefore, their detailed description will not be repeated.

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0047] Figure 1 A schematic structural diagram of a liquid crystal spectrometer provided according to an embodiment of the present invention is shown.

[0048] like Figure 1 As shown, the liquid crystal spectrometer provided by the embodiment of the present invention includes: a light source system, a beam splitter 4, a liquid crystal compensation device, a liquid crystal phase mirror 5 and a detector system.

[0049] The light source system includes a light source 1, a collimator 2, and a polarizer 3. Light source 1 emits a divergent light beam with a certain energy and specific spectral characteristics. After being collimated by collimator 2, it becomes a parallel beam that is incident on a polarizer. After being polarized by the polarizer in the polarizer, it becomes linearly polarized light, with the polarization direction of the linearly polarized light beam parallel to the light incident plane. The linearly polarized light beam emitted by polarizer 3 is incident on beam splitter 4.

[0050] The beam splitter 4 is placed at 45 degrees to the optical axis of the linearly polarized light beam. The surface of the beam splitter 4 is coated with a semi-reflective and semi-transparent film, which evenly splits the linearly polarized light beam incident on its surface into a transmitted beam and a reflected beam with equal energy.

[0051] The reflected light beam is incident on the liquid crystal compensation device after being reflected by the beam splitter 4, and then returns to the beam splitter 4 after being reflected by the liquid crystal compensation device;

[0052] The liquid crystal compensation device includes: a liquid crystal compensator 7 and a plane reflector 8; the reflected light beam is incident on the liquid crystal compensator 7 and then incident on the plane reflector 8, and then reflected by the plane reflector 8 and returned to the beam splitter 4.

[0053] The liquid crystal compensator 7 is a five-layer symmetrical structure. The first and fifth layers are transparent substrates, the second and fourth layers are alignment film layers, and the third layer is a liquid crystal layer. It has an electrodeless structure. The thickness of the liquid crystal layer of the liquid crystal compensator 7 is the same as that of the liquid crystal layer in the liquid crystal phase reflector 5. Its refractive index is n e1 , used to compensate the optical path of the transmitted light beam and the reflected light beam separated by the beam splitter 4.

[0054] The transmitted light beam is incident on the liquid crystal phase mirror 5 after being transmitted by the beam splitter 4 , and then returns to the beam splitter 4 after being reflected by the liquid crystal phase mirror 5 .

[0055] Figure 2 A schematic structural diagram of a liquid crystal phase reflector in a liquid crystal spectrometer provided according to an embodiment of the present invention is shown.

[0056] like Figure 2 As shown, the liquid crystal phase reflector 5 has a seven-layer symmetrical structure, which includes, from top to bottom, a glass cover 11, an upper transparent electrode 12, an upper alignment film 13, a liquid crystal layer 14, a lower alignment film 15, a lower transparent electrode 16, a glass substrate 17, electrode leads 18, and liquid crystal molecules 19.

[0057] The first layer is a glass cover plate 11 , which is used to fix the liquid crystal material and forms a liquid crystal cell structure with the glass substrate 17 . The upper and lower surfaces of the glass cover plate 11 are both coated with anti-reflection films.

[0058] The second layer is the upper transparent electrode 12 , which is made of indium tin oxide and serves as a driving electrode for the liquid crystal layer 14 together with the lower transparent electrode 16 .

[0059] The third layer is the upper alignment film 13 , which together with the lower alignment film 15 aligns the liquid crystal molecules 19 in the liquid crystal layer 14 , and a polyimide polymer film may be used.

[0060] The fourth layer is the liquid crystal layer 14. The liquid crystal material is nematic liquid crystal. When no driving voltage is applied, the liquid crystal molecules 19 are arranged horizontally in the liquid crystal layer 14. When the driving voltage is applied, the long axis of the liquid crystal molecules 19 points to the direction of the electric field, and the molecules are upright in the device. The thickness of the liquid crystal layer must meet

[0061] The fifth layer is the lower alignment film 15 , which together with the upper alignment film 13 aligns the liquid crystal molecules 19 , and a polyimide polymer film may be used.

[0062] The sixth layer is the lower transparent electrode 16 , which is made of indium tin oxide and serves as a driving electrode for the liquid crystal layer 14 together with the upper transparent electrode 12 .

[0063] The seventh layer is a glass substrate 17, which is used to fix the liquid crystal material and forms a liquid crystal cell structure with the glass cover 11. The upper surface is evaporated with an anti-reflection film, and the lower surface is evaporated with a high-reflection film.

[0064] The electrode leads 18 are used to connect the upper transparent electrode 12 and the lower transparent electrode 16 on both sides of the liquid crystal layer 14 to the voltage driving source 6 respectively.

[0065] Figure 3 A schematic diagram of driving voltage distribution in a liquid crystal spectrometer provided according to an embodiment of the present invention is shown.

[0066] like Figure 3 As shown, the voltage driving source 6 provides a voltage difference to the liquid crystal layer 14, driving the long axis pointing direction of the liquid crystal molecules 19 in the liquid crystal layer 14 to change.

[0067] The thickness of the liquid crystal layer 14 is L, and the liquid crystal adopts a nematic phase liquid crystal material. By providing a driving voltage source 6 between the upper transparent electrode 12 and the lower transparent electrode 16 to load a driving voltage V, the pointing inclination angle of the nematic phase liquid crystal molecules 19 in the liquid crystal layer 14 changes. The liquid crystal molecules 19 loaded with different driving voltages have different long-axis pointing inclination angles θ (V).

[0068] The change of the tilt angle of the nematic liquid crystal molecules will cause the refractive index emission of extraordinary light in the liquid crystal layer to change. Different tilt angles of the long axis of the liquid crystal molecules correspond to different refractive indices. The relationship between the refractive index of extraordinary light and the tilt angle of the liquid crystal is:

[0069] where n o 、n e are the refractive indices of ordinary light and extraordinary light in nematic liquid crystal when there is no voltage, respectively.

[0070] Therefore, the equivalent refractive index of extraordinary light in the liquid crystal caused by the driving voltage V is Therefore, the optical path of the ordinary light when it propagates in the liquid crystal is OP(V)=2n(V)L, where L is the thickness of the liquid crystal layer.

[0071] After the transmitted light beam is reflected by the rear surface of the liquid crystal layer, the phase delay of the transmitted light beam is

[0072] The transmitted light beam reflected by the liquid crystal phase mirror 5 and the reflected light beam reflected by the plane mirror 8 return to the beam splitter 4 again, and form an interference light beam after interference on the beam splitter 4 and are incident on the detector system.

[0073] The detector system includes a focusing mirror 9 and a photodetector 10 .

[0074] The interference light beam is focused by the focusing mirror 9 and then incident on the photodetector 10 , which performs photoelectric conversion to realize the collection of the interference light signal.

[0075] When the transmitted and reflected beams interfere, the optical path difference is:

[0076] δ(V)=OP(V)-2n e L=2L[n(V)-n e ]

[0077] So the interference light intensity is:

[0078]

[0079] Where B(v) is the spectral density of the linearly polarized beam, and v is the wave number of the light wave.

[0080] By varying the driving voltage, the effective refractive index of the liquid crystal layer continuously changes, which in turn causes the optical path difference between the two coherent beams to change sequentially. This results in a time-varying interference pattern function on the photodetector. By performing a discrete Fourier transform on the interference pattern function, the spectral information of the linearly polarized beam can be restored.

[0081] In order to achieve equal-interval sampling, the driving voltage is scanned in a step-by-step manner. The time scanning process of the driving voltage must ensure that the refractive index of the liquid crystal before and after modulation has the same refractive index difference Δn, that is, the refractive index value of the liquid crystal layer changes linearly with the same step size Δn, that is, n(V) = n e +kΔn, k=1,2,…,N, N is the number of sampling points.

[0082] At this time, the optical path difference sampling sequence is:

[0083] δ(k)=2kΔnL

[0084] Therefore, the sampling of the interference pattern is achieved by voltage modulating the change of the refractive index.

[0085] According to the sampling theorem, in order to achieve lossless sampling of interferogram information, the sampling interval of the optical path difference needs to satisfy the sampling theorem, that is, the optical path difference sampling interval must be less than or equal to twice the minimum wavelength of the optical signal, that is:

[0086]

[0087] Therefore, the change step size of the refractive index needs to satisfy the following relationship:

[0088]

[0089] Among them, λ min is the minimum wavelength in a linearly polarized beam.

[0090] At this point, the restored spectrum is in the form of:

[0091]

[0092] According to the discrete Fourier transform theory, the spectral resolution is the inverse of the maximum optical path difference, and the spectral resolution of the system is Therefore, the thickness of the liquid crystal layer should satisfy the relationship

[0093]

[0094] At the same time, the number of sampling points needs to satisfy the relationship where n max 、n min are the maximum and minimum refractive index values ​​that the liquid crystal material can achieve, respectively.

[0095] Figure 4 The figure shows a flow chart of a liquid crystal spectrometer measurement method according to an embodiment of the present invention.

[0096] Figure 5 A flowchart of a liquid crystal spectrometer measurement method according to an embodiment of the present invention is shown.

[0097] like Figure 4 and 5 As shown, the liquid crystal spectrometer measurement method provided by the embodiment of the present invention includes the following steps:

[0098] S1. The light source system emits a linearly polarized light beam which is incident on the beam splitter and is split into an identical reflected light beam and a transmitted light beam by the beam splitter.

[0099] Fix the collimator lens on the platform base; use a divergent laser light source with a wavelength within the system's operating spectrum band as the incident beam, adjust the distance between the laser light source and the collimator lens so that the laser light source emission point is located at the front focus of the collimator lens, and collimate the outgoing light into a parallel beam;

[0100] Place the polarizer in the collimated parallel light path and align the center; adjust the polarization direction of the polarizer in the polarizer and use the analyzer to detect the polarization direction of the parallel light beam. If the polarization direction of the parallel light beam is not parallel to the light incident plane, continue to adjust the polarization direction of the polarizer in the polarizer until the polarization direction of the parallel light beam is parallel to the light incident plane to obtain a linearly polarized beam;

[0101] S2. The transmitted light beam is reflected by the liquid crystal phase mirror and then returns to the beam splitter; the reflected light beam is transmitted by the liquid crystal compensator and reflected by the plane mirror and then returns to the beam splitter. The two light beams interfere at the exit surface of the beam splitter to form an interference beam.

[0102] Place the beam splitter in the output light path of the polarizer at an angle of 45° to the optical axis and align the center.

[0103] Place the liquid crystal compensator in the reflected light path of the beam splitter and align it centrally;

[0104] Place the plane mirror in the transmission light path of the liquid crystal compensator and align it centrally;

[0105] Place the liquid crystal phase mirror in the transmission light path of the beam splitter and align it centrally;

[0106] Adjust the relative position between the plane reflector and the liquid crystal phase reflector, and observe whether the plane reflector and the liquid crystal phase reflector are mirror-symmetrical with respect to the beam splitter and whether interference fringes are generated; if they are not in a mirror-symmetrical position or no interference fringes are generated, continue to adjust the relative position between the plane reflector and the liquid crystal phase reflector until the plane reflector and the liquid crystal phase reflector are mirror-symmetrical with respect to the beam splitter and stable interference fringes are generated;

[0107] S3. The interference light beam is incident on the detector system to obtain an interference light signal and acquire the spectral information of the linearly polarized light beam.

[0108] Place the focusing mirror in the outgoing light path of the plane reflector and align the center;

[0109] Place a single-point detector at the focal point of the focusing mirror and adjust its position relative to the focusing mirror to maximize energy. Replace the laser light source with a broadband light source. Adjust the scanning voltage applied between the two transparent electrodes of the liquid crystal phase reflector until the refractive index difference of the liquid crystal material before and after each step scan is the same. Fix the scanning voltage of the liquid crystal phase reflector.

[0110] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

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

Claims

1. A liquid crystal spectrometer, characterized in that: include: Light source system, beam splitter, liquid crystal compensation device, liquid crystal phase reflector and detector system; The light source system is configured to emit a linearly polarized light beam which is incident on the beam splitter and is split by the beam splitter into a transmitted light beam and a reflected light beam. The reflected light beam is incident on the liquid crystal compensation device, is reflected, and then returns to the beam splitter. The transmitted light beam is incident on the liquid crystal phase reflector, is reflected, has a preset optical path difference, and returns to the beam splitter to interfere with the reflected light beam to form an interference light beam which is incident on the detector system to obtain an interference light signal and acquire spectral information of the linearly polarized light beam. Providing a voltage difference to the liquid crystal layer of the liquid crystal phase reflector through a voltage driving source, so as to drive the long axis pointing direction of the liquid crystal molecules in the liquid crystal layer to change; When different driving voltages V are applied, the liquid crystal molecules in the liquid crystal layer have different long axis pointing inclination angles. θ ( V ); Different liquid crystal molecule long axis pointing angles correspond to different refractive indices; the relationship between the refractive index of extraordinary light and the liquid crystal pointing angle is: ; Among them, n o 、n e are the refractive indices of ordinary light and extraordinary light in the liquid crystal layer when there is no voltage, respectively; The equivalent refractive index of the extraordinary light in the liquid crystal caused by the driving voltage V is , so the optical path of extraordinary light when it propagates in the liquid crystal is ; Wherein, L is the thickness of the liquid crystal layer; After the transmitted light beam is reflected by the liquid crystal phase reflector, the phase delay is ; The driving voltage source adopts a step-by-step scanning method, that is, the refractive index of the liquid crystal layer is scanned in the same step size. The refractive index changes linearly: ; Where k=1,2,…,N, N is the number of sampling points; At this time, the optical path difference sampling sequence is: ； The step size of the refractive index change The following relationship is satisfied: Among them, λ min is the minimum wavelength in the linearly polarized light beam.

2. The liquid crystal spectrometer according to claim 1, characterized in that: The light source system includes: a light source, a collimator and a polarizer; The light source is used to emit a divergent light beam, the collimator collimates the divergent light beam into a parallel light beam and then the light beam is incident on the polarizer; the polarizer converts the parallel light beam into a linearly polarized light beam and then the linearly polarized light beam is incident on the beam splitter.

3. The liquid crystal spectrometer according to claim 2, characterized in that: The liquid crystal compensation device includes: a liquid crystal compensator and a plane reflector; The reflected light beam is reflected by the beam splitter, passes through the liquid crystal compensator and is incident on the plane reflective mirror; and is reflected again by the plane reflective mirror, passes through the liquid crystal compensator and is incident on the beam splitter; The liquid crystal compensator is used to compensate the optical paths of the transmitted light beam and the reflected light beam separated by the beam splitter.

4. The liquid crystal spectrometer according to claim 3, characterized in that: The liquid crystal phase reflector comprises, from top to bottom, a glass cover, an upper transparent electrode, an upper alignment film, a liquid crystal layer, a lower alignment film, a lower transparent electrode and a glass substrate; The glass cover plate and the glass substrate form a liquid crystal cell structure for fixing the liquid crystal layer; the upper and lower surfaces of the glass cover plate are coated with anti-reflection films, and the upper surface of the glass substrate is evaporated with an anti-reflection film, and the lower surface is evaporated with a high-reflection film; The upper transparent electrode and the lower transparent electrode serve together as driving electrodes for the liquid crystal layer; The upper alignment film and the lower alignment film together align the liquid crystal molecules in the liquid crystal layer; the material of the liquid crystal layer is nematic liquid crystal; The electrode leads are used to connect the upper transparent electrode and the lower transparent electrode to a voltage driving source respectively.

5. The liquid crystal spectrometer according to claim 1, characterized in that: The detector system includes: a focusing mirror and a photoelectric detector; The interference light beam is converged by the focusing mirror and incident on the photoelectric detector, and the photoelectric detector performs photoelectric conversion to realize the collection of interference light signals.

6. A measurement method for a liquid crystal spectrometer according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The light source system emits a linearly polarized light beam which is incident on the beam splitter and is split by the beam splitter into an identical reflected light beam and a transmitted light beam; S2, the transmitted light beam is reflected by the liquid crystal phase reflector and then returns to the beam splitter; the reflected light beam is transmitted by the liquid crystal compensator and reflected by the plane reflector and then returns to the beam splitter, and the two light beams interfere at the exit surface of the beam splitter to form an interference light beam; S3. The interference light beam is incident on a detector system to obtain an interference light signal, and spectrum information of the linearly polarized light beam is acquired.

Images