A visible light interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets

Abstract

The present invention discloses a visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets. The system designed by the present invention has a working center wavelength of 519.5nm and a bandwidth of 2nm; the system is composed of three modules: a collimation system, a spectroscopic system, and a focusing system, wherein the spectroscopic system is the core module of the system, which is composed of an interferometer module and a Wollaston prism polarization module. The interferometer module is made of two prisms of different materials glued together, and can output two interference lights with a phase difference of π. After the interference light is incident on the Wollaston prism, it is divided into four beams of polarized light with a phase difference of π / 2. The system can simultaneously obtain characteristic images of 4 different phases of the same scene. The interferometric polarization imaging spectrometer in the present invention has a compact structure, the core module has good stability, and the MTF of the full field of view at the Nyquist frequency is greater than 0.55, and has good imaging quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of imaging spectroscopy, and in particular relates to a visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets. Background Art

[0002] The convection movement of energy transmitted to the inner surface of the gas planet drives the superposition of natural sound waves in the atmosphere of the gas planet. When the superimposed sound waves propagate to the surface of the planet's atmosphere, they cause atmospheric oscillations. The frequency and mode of the oscillations contain information about the internal structure of the planet, and the higher the order, the richer the information contained. Because the atmospheric oscillations caused by the superimposed sound waves will cause the Doppler shift of the spectral lines of the solar spectrum reflected by the gas planet, if the Doppler shift of the solar spectrum reflected by the planet's surface can be detected, the oscillation mode of the planet's surface can be inverted, and thus the internal structure of the planet can be obtained.

[0003] Interferometer is an important means to achieve the above detection purposes. When a light beam of known spectrum is incident on the interferometer, the Doppler frequency shift of the spectrum line will cause the interference fringes to produce phase shift, so the spectrum measurement problem can be converted into the phase measurement problem of the interference fringes. Common interferometer structures include Michelson structure, FP structure and MZ structure. Under the same conditions, MZ interferometer is easier to achieve high precision and high stability. Therefore, in order to achieve high-precision measurement of high-order oscillation modes of the target planet, the present invention selects the MZ interferometer structure and further improves it. At the same time, multi-phase images can improve the detection accuracy of high-order starquakes. In order to simultaneously realize multi-phase measurement of the target reflected solar spectrum, the present invention comprehensively considers adding a Wollaston prism polarization module, which cooperates with the interferometer module to achieve the detection purpose. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets. The present invention is composed of a collimation system, a spectroscopic system, and a focusing system, and can achieve good imaging capabilities in the working band. The whole system has a compact structure, and the core module spectroscopic system has good stability, which is suitable for the field of remote sensing.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets, comprising a collimation system, a spectroscopic system and a focusing system; the collimation system comprises a filter, a first convex lens, a concave lens and a first meniscus lens; the spectroscopic system comprises an interferometer module and a Wollaston prism polarization module; the interferometer module comprises a first prism and a second prism; the Wollaston prism polarization module comprises a first Wollaston prism, a first plane reflector, a second plane reflector and a second Wollaston prism; the focusing system comprises a second convex lens, a second meniscus lens, a third meniscus lens, a first detector, a third convex lens, a fourth meniscus lens, a fifth meniscus lens and a second detector;

[0007] The solar spectrum reflected from the surface of the target to be measured is imaged onto the filter through the telescope system, the stray light spectrum is filtered out, and then collimated into parallel light through the first convex lens, the concave lens, and the first meniscus lens; the collimated parallel light is incident on the interface between the first prism and the second prism to interfere, and two interference lights with a phase difference of π are emitted, and the two interference lights pass through the first Wollaston prism and the second Wollaston prism respectively, and are divided into four polarized lights; the outgoing interference light of the first prism is incident on the first Wollaston prism, and is divided into two polarized lights with a phase difference of π / 2, and then the two polarized lights are split into The two polarized lights are focused by the second convex lens, the second meniscus lens and the third meniscus lens to form an image on the first detector; the interference light emitted from the second prism is adjusted in direction by the first plane reflector and the second plane reflector to be parallel to the direction of the emitted light from the first prism; the light beam after direction adjustment is incident on the second Wollaston prism and is divided into two polarized lights with a phase difference of π / 2, and then the two polarized lights are focused by the third convex lens, the fourth meniscus lens and the fifth meniscus lens to form an image on the second detector; that is, the four polarized lights are formed by two groups of focusing lenses to form an image on two detectors, so as to obtain four images of the same scene with a phase difference of π / 2.

[0008] Furthermore, the first detector and the second detector are CCD detectors with a pixel size of 9 microns and 4096×4096 pixels, and the MTF of the full field of view at the Nyquist frequency is greater than 0.55.

[0009] Furthermore, the first prism and the second prism are made of different materials and are glued together to form the interferometer module, and a semi-transparent and semi-reflective film is coated on the interface between the two.

[0010] Furthermore, its operating center wavelength is 519.5nm, bandwidth is 2nm, and F number is 10.

[0011] Furthermore, according to the requirements of the observation of the reflected solar spectrum of the gaseous planet, a suitable central wavelength and band are selected, and the filter of the optical system is replaced to realize the observation. The advantages of the present invention are as follows:

[0012] (1) A filter is set on the object plane of the system to filter out stray light outside the 518.5nm-520.5nm band, and the transmittance outside the cut-off band is ≤1%;

[0013] (2) The spectroscopic system consists of an interferometer module and a Wollaston prism polarization module. The interferometer module is an improved MZ interferometer system, which is made of two prisms of different materials glued together. A semi-transparent and semi-reflective film is coated on the interface between the first prism and the second prism to achieve the spectroscopic separation of the incident light. Because the two prisms are made of different materials, the optical paths of the transmitted light and the reflected light are different, and there is an optical path difference. Therefore, when the two beams of light intersect, interference will occur and the phase will shift. The direction of the outgoing light from the second prism is adjusted by the first plane reflector and the second plane reflector to make it parallel to the direction of the outgoing light from the first prism.

[0014] The Wollaston prism polarization module consists of a first Wollaston prism, a first plane reflector, a second plane reflector, and a second Wollaston prism. The Wollaston prism is formed by gluing two right-angle prisms together, wherein the angle between the gluing surface of the right-angle prism and the incident surface is 35°, and the optical axes of the two right-angle prisms are perpendicular to each other. Because the light beams incident on the two Wollaston prisms are parallel to each other, and the Wollaston prisms are also parallel to each other, the outgoing light beams of the Wollaston prisms are also parallel to each other. The subsequent focusing system can use two groups of lenses to focus and image the outgoing light.

[0015] (3) The collimation system, the spectroscopic system, and the focusing system are designed separately, and then matched and optimized to obtain the final optimized system design.

[0016] The present invention can simultaneously obtain characteristic images of four different phases of the same scene; the core module has a compact structure and good stability; and has good engineering applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a light path design diagram of the visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets according to the present invention.

[0018] Figure 2 It is a design diagram of the light splitting path of the core module of the interference polarization imaging spectrometer of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] The visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets of the present invention has a working center wavelength of 519.5 nm, a bandwidth of 2 nm, and an F number of 10. Figure 1 As shown, the visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets of the present invention is composed of three parts: a collimation system, a spectroscopic system and a focusing system. The collimation system is composed of a filter 1, a first convex lens 2, a concave lens 3, and a first meniscus lens 4. The spectroscopic system is composed of an interferometer module and a Wollaston prism polarization module. The interferometer module is composed of a first prism 5 and a second prism 6. The Wollaston prism polarization module is composed of a first Wollaston prism 7, a first plane reflector 12, a second plane reflector 13, and a second Wollaston prism 14. The focusing system is composed of a second convex lens 8, a second meniscus lens 9, a third meniscus lens 10, a first detector 11, a third convex lens 15, a fourth meniscus lens 16, a fifth meniscus lens 17, and a second detector 18.

[0021] The filter 1 coincides with the focal plane of the telescope system at the front end, and the solar spectrum reflected by the target surface to be measured is imaged to the filter 1 through the telescope system, and the stray light spectrum is filtered out, and then collimated into parallel light through the collimation system; the collimated parallel light is incident on the interface between the first prism 5 and the second prism 6, and is divided into transmitted light and reflected light. Because the optical paths of the two beams of light are different, interference will occur when the two beams of light intersect, and the phase changes, so the parallel light is incident on the interferometer module to interfere, and two beams of interference light with a phase difference of π are emitted, and the two beams of interference light are respectively divided into four beams of polarized light through the first Wollaston prism 7 and the second Wollaston prism 14 of the light splitting system; specifically, the outgoing interference light of the first prism 5 is incident on the first Wollaston prism 7, and is divided into two beams of polarized light with a phase difference of π / 2, and then the two beams of polarized light are respectively focused and imaged on the first detector 11 through the second convex lens 8, the second meniscus lens 9 and the third meniscus lens 10. The outgoing interference light of the second prism 6 is adjusted in direction by the first plane reflector 12 and the second plane reflector 13 to be parallel to the outgoing light direction of the first prism 5. The adjusted light beam is incident on the second Wollaston prism 14 and is divided into two polarized light beams with a phase difference of π / 2. Then, the two polarized light beams are focused and imaged on the second detector 18 by the third convex lens 15, the fourth meniscus lens 16 and the fifth meniscus lens 17, that is, the four polarized light beams are formed by two groups of focusing lenses and imaged on the two detectors to obtain four images of the same scene with a phase difference of π / 2. The first detector 11 and the second detector 18 are CCD detectors with a pixel size of 9 microns and 4096×4096 pixels. The MTF of the full field of view at the Nyquist frequency is greater than 0.55, and the whole system has good imaging quality. According to different actual application requirements, CCD or CMOS detectors with different pixels can be replaced, and the optical performance can still be guaranteed.

[0022] like Figure 2As shown, the core module of the visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets of the present invention is a spectroscopic system, which is composed of an interferometer module and a Wollaston prism polarization module, wherein the spectroscopic system shares a front-end collimation system. The interferometer module is formed by gluing a first prism 5 and a second prism 6 made of two different materials, and a semi-transparent and semi-reflective film is coated on the interface between the two. When the light beam is incident on the interface, it is divided into a transmitted light beam and a reflected light beam; because of the different materials, the optical path of the transmitted light and the reflected light is different, and the phases of the two light beams also change; when the two light beams are reflected by the prism and incident on the interface again and intersect, interference occurs, and the outgoing light has a fixed phase difference of π. The two outgoing lights of the interferometer module are then directly incident on the first Wollaston prism 7 and the second Wollaston prism 14 or are deflected by the first plane reflector 12 and the second plane reflector 13 and then incident on the first Wollaston prism 7 and the second Wollaston prism 14. The special properties of the Wollaston prism will cause the incident light to be divided into two polarized lights with mutually perpendicular vibration directions, and finally form four light beams with a phase difference of π / 2, which are focused by two groups of focusing lenses and imaged on two detectors.

[0023] The present invention is an interference polarization imaging spectrometer system that can simultaneously obtain characteristic images of four different phases of the same scene. It inverts high-order atmospheric oscillations on the surface of the planet to be measured by measuring the phase change of interference fringes. When the incident spectrum contains N absorption lines and the lines are arranged at equal intervals, the phase change of the interference fringes will be proportional to the Doppler shift of the solar spectrum reflected from the planetary surface, and the phase change is most sensitive to the Doppler shift of the spectrum. Based on this, for the analysis of the solar spectrum reflected by Jupiter, the reflected solar spectrum within the band range of 518.5nm-520.5nm can meet the requirements. For the observation of the reflected solar spectrum of other gaseous planets, the appropriate central wavelength and band can be selected as required, and the filter 1 of the optical system can be replaced.

[0024] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A visible light interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets. Features: It is composed of a collimation system, a spectroscopic system and a focusing system; the collimation system is composed of a filter, a first convex lens, a concave lens, and a first meniscus lens; the spectroscopic system is composed of an interferometer module and a Wollaston prism polarization module; the interferometer module is composed of a first prism and a second prism; the Wollaston prism polarization module is composed of a first Wollaston prism, a first plane reflector, a second plane reflector, and a second Wollaston prism; the focusing system is composed of a second convex lens, a second meniscus lens, a third meniscus lens, a first detector, a third convex lens, a fourth meniscus lens, a fifth meniscus lens, and a second detector; The solar spectrum reflected from the surface of the target to be measured is imaged onto the filter through the telescope system, the stray light spectrum is filtered out, and then collimated into parallel light through the first convex lens, the concave lens, and the first meniscus lens; the collimated parallel light is incident on the interface between the first prism and the second prism to interfere, and two interference lights with a phase difference of π are emitted, and the two interference lights pass through the first Wollaston prism and the second Wollaston prism respectively, and are divided into four polarized lights; the outgoing interference light of the first prism is incident on the first Wollaston prism, and is divided into two polarized lights with a phase difference of π / 2, and then the two polarized lights are split into The two polarized lights are focused by the second convex lens, the second meniscus lens and the third meniscus lens to form an image on the first detector; the interference light emitted from the second prism is adjusted in direction by the first plane reflector and the second plane reflector to be parallel to the direction of the emitted light from the first prism; the light beam after direction adjustment is incident on the second Wollaston prism and is divided into two polarized lights with a phase difference of π / 2, and then the two polarized lights are focused by the third convex lens, the fourth meniscus lens and the fifth meniscus lens to form an image on the second detector; that is, the four polarized lights are formed by two groups of focusing lenses to form an image on two detectors, so as to obtain four images of the same scene with a phase difference of π / 2.

2. A visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets according to claim 1, Features: The first detector and the second detector are CCD detectors with a pixel size of 9 microns and 4096×4096 pixels, and the MTF of the full field of view at the Nyquist frequency is greater than 0.

55.

3. A visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets according to claim 1, Features: The first prism and the second prism are made of different materials and are glued together to form the interferometer module. A semi-transparent and semi-reflective film is coated on the interface between the two.

4. A visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets according to any one of claims 1 to 3, Features: Its operating center wavelength is 519.5nm, bandwidth is 2nm, and F number is 10.

5. A visible light band interferometric polarization imaging spectrometer for detecting high-order oscillation modes of gaseous planets according to any one of claims 1 to 3, Features: According to the requirements of the reflected solar spectrum observation of the gas planet, select the appropriate central wavelength and band, and replace the filter of the optical system to realize the observation.

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