Michelson interferometer and method for measuring refractive index change of liquid crystal optical component

Abstract

The present invention relates to the field of measuring the refractive index change of liquid crystal optical components caused by radiation effects, and specifically relates to a Michelson interferometer and a method for measuring the refractive index change of liquid crystal optical components. The Michelson interferometer of the present invention is used to realize in-situ testing of the spatial radiation environment effect of liquid crystal optical components. The interferometer is composed of a laser, a collimating beam expander lens, a beam splitter, a horizontal tilt reflector, a vertical reflector, a focusing lens, a liquid crystal device (CCD), and a radiation source. The liquid crystal device is placed between the beam splitter and the vertical reflector. The liquid crystal device is connected to a liquid crystal drive power supply. The vertical reflector is an aluminum plate with a smooth mirror surface on the front and a non-through small hole on the back. Rays are emitted from the radiation source and vertically illuminate the back of the vertical reflector, penetrating the bottom of the small hole to achieve localized irradiation of the liquid crystal. By comparing the distortion of the interference fringes in the CCD with and without irradiation, the refractive index of the irradiated liquid crystal area is calculated.

Description

Technical Field

[0001] The present invention relates to the field of measuring the refractive index change of liquid crystal optical components caused by radiation effects, and in particular to a Michelson interferometer and a method for measuring the refractive index change of liquid crystal optical components. More specifically, the present invention relates to a Michelson interferometer for in-situ testing the performance impact of a space radiation environment on liquid crystal optical components and a method for measuring the refractive index change of liquid crystal optical components. Background Art

[0002] Liquid crystal optical components are widely used in space optics applications, including high-definition three-dimensional imaging for satellite remote sensing and space-based astronomical observation. However, these components are inevitably exposed to the harsh radiation environment of space. High-energy ionizing radiation, such as protons and electrons, originating from Earth's radiation belts, the solar wind, and cosmic rays, can have unpredictable effects on the performance of liquid crystal variable phase retarders, reducing the reliability of related optical observations. However, there are currently no dedicated space flight experiments investigating the performance degradation of liquid crystal optical components in space radiation environments. Therefore, ground-based experiments using proton and electron accelerators and radiation sources have become a viable alternative for effectively evaluating the effects of space radiation on liquid crystal optical components.

[0003] To date, although some institutions at home and abroad have conducted ground-based tests on the effects of space radiation on liquid crystal optical components with specific functions, these tests are essentially offline. Specifically, after irradiating the liquid crystal optical component with a certain dose of ionizing radiation, the component is removed and the performance changes after irradiation are measured using optical testing instruments such as ellipsometers. Obviously, this offline testing cannot fully and accurately reflect the impact of ionizing radiation on liquid crystal performance. Typically, after irradiation, for safety reasons, researchers must wait until the radiation dose in the optical component or the experimental environment drops below a safe level before conducting subsequent optical measurements. This waiting time increases with increasing radiation dose. However, existing offline measurements have consistently found that the refractive index of liquid crystals exhibits strong recovery after irradiation. This means that only in-situ measurements, which combine irradiation and testing, can accurately determine the true refractive index changes of liquid crystal optical components under constant radiation exposure in space.

[0004] The key technical points for achieving ground-based in-situ testing of the effects of space radiation on liquid crystal optical components are: (1) considering how to simultaneously introduce laser test beams and ionizing radiation into the liquid crystal refractive index test, and implementing adequate shielding of the ionizing radiation to protect sensitive optical devices such as lasers and CCDs (charge coupled devices); (2) considering how to evaluate and eliminate the noise generated by ionizing radiation on the results of in-situ testing; and (3) considering how to achieve remote observation and control. Currently, most measurements of changes in the refractive index of liquid crystal optical components caused by radiation effects are performed offline. That is, after a certain amount or dose of radiation is applied to the liquid crystal optical component, the liquid crystal optical component is removed from the radiation environment and the refractive index of the liquid crystal optical component is measured using an ellipsometer or other device. By comparing the refractive index before and after irradiation, the refractive index change caused by the radiation effect is obtained.

[0005] In actual experiments, the liquid crystal components are typically not removed from the experimental chamber immediately after irradiation. This is especially true after high-dose irradiation, as the liquid crystal components themselves become radioactive. For safety reasons, further optical testing must be performed only after the radioactivity has dropped below a safe level. Liquid crystals, however, have a strong ability to recover from refractive index changes caused by radiation effects. After irradiation ceases, their refractive index quickly relaxes to its pre-irradiation value. This results in offline measurements being unable to accurately reflect the true refractive index of the liquid crystal material under real-time irradiation. Summary of the Invention

[0006] The present invention aims to provide a method for in-situ measurement of the radiation effects on liquid crystal components, enabling more accurate determination of their refractive index under real-time irradiation. To address these challenges, the present invention proposes a Michelson interferometer that meets these technical requirements and enables ground-based in-situ testing of the effects of space radiation on liquid crystal optical components.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0008] The present invention proposes a Michelson interferometer, which is used to measure the change in the refractive index of a liquid crystal optical component affected by radiation. The Michelson interferometer includes: a beam splitter, a horizontally tilted reflector, and a vertical reflector. The Michelson interferometer also includes: a liquid crystal device and a radiation source; wherein,

[0009] The back of the vertical reflector is provided with a non-through hole; a thin layer of a predetermined thickness is provided at the bottom of the non-through hole; the liquid crystal device is placed between the beam splitter and the vertical reflector; the liquid crystal optical component is placed in the liquid crystal device; and the radiation source is placed on the back of the vertical reflector;

[0010] The beam splitter is used to split the parallel light beam incident on the beam splitter into two light beams, one light beam is incident on the horizontal tilt reflector, and the other light beam passes through the liquid crystal device and is incident on the vertical reflector;

[0011] The horizontally tilted reflector is used to reflect the incident light beam to the beam splitter; the light beam reflected to the beam splitter is transmitted through the beam splitter;

[0012] The vertical reflector is used to reflect the incident light beam; the light beam reflected by the vertical reflector passes through the liquid crystal device and is then reflected by the beam splitter;

[0013] The light beam transmitted by the beam splitter and the light beam reflected by the beam splitter converge at the beam splitter to form an interference light beam;

[0014] The radiation source is used to generate radiation rays; the radiation rays penetrate the non-penetrating holes and irradiate a part of the liquid crystal optical component in the liquid crystal device.

[0015] As one of the improvements of the above technical solution, the Michelson interferometer further includes: a laser, a 45-degree angle reflector and a collimating beam expander; wherein,

[0016] The laser is used to emit a linearly polarized laser beam, which is incident on a 45-degree angle reflector;

[0017] The 45-degree angle reflector is used to reflect the incident light beam so that the reflected light beam is perpendicular to the light beam emitted by the laser and is incident on the collimating beam expander;

[0018] The collimating beam expander is used to expand the incident light beam into an extended parallel light beam, and the spot diameter of the parallel light beam is larger than the diameter of the non-penetrating pinhole.

[0019] As one of the improvements of the above technical solution, the Michelson interferometer further includes: a focusing lens, a CCD, a liquid crystal driving power supply and a computer; wherein,

[0020] The condenser lens is used to converge the interference light beam;

[0021] The CCD is used to process the converged interference light beam to obtain interference fringes, including interference fringes when the radiation source is turned on and interference fringes when the radiation source is turned off; and is also used to obtain the distortion amount of the interference fringes based on the interference fringes when the radiation source is turned on and the interference fringes when the radiation source is turned off;

[0022] The liquid crystal driving power supply is used to provide voltage to the liquid crystal optical component and adjust the orientation of molecules in the liquid crystal optical component by providing a changed voltage, thereby changing the refractive index of the liquid crystal in the propagation direction of the light beam;

[0023] The computer is used to calculate the change in the refractive index of the irradiated part of the liquid crystal optical component based on the distortion of the interference fringes; and is also used to control the liquid crystal driving power supply.

[0024] As one of the improvements of the above technical solution, the vertical reflector is grounded; the material of the vertical reflector is an aluminum plate; the front surface of the vertical reflector is a polished and smooth mirror surface.

[0025] As one of the improvements of the above technical solution, the distortion of the interference fringes is the change in the width and position of the interference fringes.

[0026] As one of the improvements of the above technical solution, the radiation source is an electron gun, a proton gun, an electron accelerator or a proton accelerator.

[0027] As one of the improvements of the above technical solution, the thickness of the thin layer at the bottom of the small hole should be able to ensure the transmission of radiation rays.

[0028] As one of the improvements of the above technical solution, the liquid crystal device includes a liquid crystal box; the liquid crystal box is a box body with upper and lower end surfaces and open on all sides, which is used for loading and unloading liquid crystal optical components.

[0029] The present invention also proposes a method for measuring the refractive index change of a liquid crystal optical component using a Michelson interferometer. The method measures the change in the refractive index of the liquid crystal optical component caused by radiation using one of the above-mentioned Michelson interferometers. The method comprises:

[0030] Step S1. Turn off the radiation source;

[0031] Step S2. Turn on the laser and CCD, adjust the position of the horizontal tilt mirror, the vertical mirror and / or the voltage provided by the liquid crystal drive power supply, and obtain interference fringes when the radiation source is turned off through the CCD;

[0032] Step S3. Turn on the radiation source and obtain interference fringes when the radiation source is turned on through the CCD;

[0033] Step S4. Observe the distortion ΔD' of the interference fringes in steps S2 and S3 through the CCD;

[0034] Step S5. Calculate the change in refractive index Δn of the irradiated portion of the liquid crystal optical component using a computer based on the distortion ΔD′ of the interference fringes.

[0035] As an improvement to the above technical solution, the method further includes:

[0036] Step S6. Remove the liquid crystal device and obtain interference fringes when the radiation source is turned off and on through the CCD respectively. By comparing the interference fringes in the two states, obtain the distortion ΔD" of the interference fringes in the CCD25 caused by the irradiation environment acting on other components in the Michelson interferometer except the liquid crystal device when the liquid crystal device is not present, and calculate the distortion difference ΔD = ΔD'-ΔD", and use ΔD to further correct Δn.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] 1. According to the present invention, the change in the refractive index of the irradiated liquid crystal portion can be measured in real time when the liquid crystal component is irradiated by high-energy charged particles simulating a space radiation environment.

[0039] 2. According to the present invention, by cleverly utilizing the penetrability of high-energy charged particles into thin metal layers, a non-penetrating small hole is designed on the back of the reflector so that high-energy charged particles can penetrate the thin metal layer at the bottom of the small hole to locally irradiate the liquid crystal component. At the same time, it can ensure that most of the radiation rays are isolated from the optical components in the Michelson optical path.

[0040] 3. According to the present invention, by adjusting the parameters of the radiation device, the change in the refractive index of the irradiated liquid crystal part under different irradiation energies and doses can be conveniently and directly measured, and the problem of frequently taking out the liquid crystal optical components for additional testing in traditional solutions is avoided.

[0041] 4. According to the present invention, it is possible to conveniently test and verify the working reliability of transmission optical lenses made of other materials in a space radiation environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The full optical path diagram of the Michelson interferometer of the present invention is shown;

[0043] Figure 2 for Figure 1 A perspective view of the liquid crystal device shown in ;

[0044] Figure 3 for Figure 2 Schematic diagram of the multilayer film structure of the liquid crystal lens shown in;

[0045] Figure 4 for Figure 1 A perspective view of the vertical reflector shown in ;

[0046] Figure 5 for Figure 1 A side cross-sectional view of the reflector setup shown in FIG.

[0047] Figure ID

[0048] 9. Laser 10. Laser beam 11. Expanded parallel beam

[0049] 12. 45-degree reflector 13. Collimating beam expander lens 14. Beam splitter

[0050] 15. Reflected beam 16. Horizontally tilted reflector 17. Transmitted beam

[0051] 18. Liquid crystal device 19. Vertical reflector 20. Radiation source

[0052] 21. Rays 22. Transmitted rays 23. Interference beams

[0053] 24. Focusing lens 25. CCD 26. Computer

[0054] 27. LCD driver power supply 28. Video cable 29. Network cable

[0055] 30. Non-through hole 31. Liquid crystal lens 32. Liquid crystal box top

[0056] 33, liquid crystal cell bottom 34, liquid crystal cell column 40, liquid crystal layer

[0057] 41. Polyimide layer 42. ITO layer 43. Glass layer DETAILED DESCRIPTION

[0058] The present invention provides a double-arm Michelson interferometer comprising a beam splitter 14, a horizontally tilted reflector 16, a vertical reflector 19, a liquid crystal device 18, a CCD 25, a radiation source 20, and a liquid crystal driving power supply 27, wherein:

[0059] The liquid crystal device 18 is placed between the beam splitter and the vertical reflector;

[0060] The liquid crystal device 18 includes a liquid crystal box and a liquid crystal optical component. The liquid crystal optical component is a transmissive type and can be installed and removed from the liquid crystal box. The liquid crystal optical component is connected to the liquid crystal driving power supply 27.

[0061] The radiation source 20 is placed on the back side of the vertical reflector.

[0062] Furthermore, it has two working states, namely, state 1 in which the radiation source 20 does not emit a beam; and state 2 in which the radiation source 20 emits a beam.

[0063] Furthermore, in the state 1, basic interference fringes are observed on the CCD by adjusting the liquid crystal driving voltage connected to the liquid crystal optical component.

[0064] Furthermore, the vertical reflector 19 is constructed of a 40mm thick aluminum plate. Its front surface is a polished, smooth mirror surface, while its back surface faces the radiation source and has a non-through aperture. The aperture has a diameter of approximately 2mm and a depth of 39.9mm. In State 2, the radiation penetrates the bottom of the aperture and partially irradiates the liquid crystal device 18.

[0065] Furthermore, the vertical reflector 19 is grounded.

[0066] Furthermore, by comparing the interference fringes observed by the CCD in the working states 1 and 2, the changes in the width and position of the interference fringes caused by local irradiation of the liquid crystal device 18 are obtained, and the change in the refractive index of the liquid crystal caused by the irradiation is further calculated.

[0067] Furthermore, the radiation source 20 may be an electron gun, a proton gun, or an ionizing ray generating device such as an electron accelerator or a proton accelerator.

[0068] Furthermore, the CCD 25 and the liquid crystal driving power supply 27 are connected to an external computer via a video cable and a network cable respectively to achieve remote monitoring and control.

[0069] The technical solution provided by the present invention is further illustrated below with reference to embodiments.

[0070] Example 1

[0071] The Michelson interferometer of the present invention can be used to realize in-situ testing of space irradiation effects of liquid crystal optical components. Figure 1 As shown, the Michelson interferometer consists of a laser 9, a reflector 12, a collimating and expanding lens 13, a beam splitter 14, a horizontally tilted reflector 16, a vertical reflector 19, a liquid crystal device 18, a focusing lens 24, a CCD 25, a radiation device 20, and a remote computer 26. The liquid crystal device 18 is placed between the beam splitter 14 and the vertical reflector 19. The liquid crystal device 18 is connected to a liquid crystal driving power supply 27. The liquid crystal driving power supply 27 and the CCD 25 are each connected to the remote computer 26. The vertical reflector 19 is an aluminum plate with a non-penetrating aperture 30 on the back. High-energy particle beams 21 are emitted from the radiation source 20, perpendicularly irradiating the back of the vertical reflector 19 and partially irradiating the liquid crystal device 18 through the non-penetrating aperture 30. By comparing the changes in the width and spacing of the interference fringes in the CCD 25 with and without irradiation, the change in the local refractive index of the liquid crystal caused by the irradiation can be inferred.

[0072] The Michelson interferometer of the present invention has two working states, namely, state 1 when the radiation device does not emit a beam, and state 2 when the irradiation device emits a beam. When the Michelson interferometer of the present invention is used to measure the refractive index, Figure 1As shown, first, in state 1, the basic optical path is set up, and by adjusting the positions of the horizontal tilt mirror 16 and the vertical reflector 19, basic interference fringes can be observed in CCD25. The interference fringes produced by the Michelson interferometer of this invention are vertically parallel light and dark staggered fringes under equal thickness interference. At this time, the voltage is provided by the liquid crystal drive power supply 27, and the overall movement of the equal thickness interference fringes can be observed in CCD25. Then turn on the radiation device (i.e., the radiation source 20), that is, state 2. At this time, the charged particle beam 21 is emitted by the radiation device 20, and forms a transmitted particle beam 22 through the small hole 30 provided on the vertical reflector 19. The transmitted particle beam 22 is irradiated onto the liquid crystal lens 31 in the liquid crystal device 18 (see Figure 2 ) portion of the surface. At this point, the distortion ΔD' of the interference fringes corresponding to the illuminated portion of the liquid crystal can be observed on CCD 25. The refractive index change Δn of the illuminated portion of the liquid crystal can be calculated using ΔD'.

[0073] like Figure 1 As shown, in the Michelson interferometer of the present invention, the radiation device 20 can be a low-energy electron gun or proton gun, or a medium- or high-energy electron or proton accelerator, etc., which generates electron or proton charged particle beam 21. The energy and beam intensity of the charged particle beam are adjustable. For accelerator facilities, the irradiation experimental hall must be locked and personnel must be cleared during operation. The electron and proton beams are then adjusted using a remote control device in the control hall. During the experiment, the optical path of the Michelson interferometer of the present invention must first be set up in the irradiation experimental hall. At this time, it is important to place optical devices such as the laser 9 and CCD 25 away from direct exposure to the particle beam 21. If necessary, an aluminum plate approximately 5 cm thick can be used to shield the laser 9, CCD 25, and other devices to further reduce the damage they suffer from scattered ionizing radiation. The CCD 9 and LCD driver power supply 27 are connected to the display and host computer of a remote computer 26 outside the experimental hall via a video cable 28 and a network cable 29, respectively. After the Michelson interferometer optical path is built, the Michelson interferometer is debugged without irradiating the beam until clear light and dark interference fringes can be observed in the CCD25 field of view, and then the ray device is turned on and enters state 2.

[0074] like Figure 1As shown, during the debugging process of the Michelson interferometer of the present invention, the laser 9 provides an incident light beam 10. The light beam 10 is reflected by a 45-degree angle mirror 12 and then enters the collimating beam expander 13. This ensures that the laser 9 and the ray 22 are perpendicular to each other, thereby preventing the ray 22 from directly hitting the laser 9. The laser beam 10 is expanded into an expanded parallel beam 11. After the expanded parallel beam 11, it is incident on the beam splitter 14 for splitting, resulting in light 15 and light 17. Light 15 is reflected light, which is reflected again by the horizontally tilted mirror 16 and returns to the beam splitter 14; light 17 is transmitted light, which passes through the liquid crystal device 18, then reflects by the vertical mirror 19, and then passes through the liquid crystal device 18 again and returns to the beam splitter 14. Light 15 and light 17 reconverge at the beam splitter to form an interference beam 23. After being converged by the converging lens 24, the interference beam is incident on the camera of CCD 25.

[0075] like Figure 1 As shown, in the Michelson interferometer of the present invention, the tilt angle of the horizontal tilt mirror 16 can be set to 5-10 degrees from the horizontal direction. According to the basic interference theory of the Michelson interferometer, in the absence of irradiation, the basic interference fringes observed in the CCD 25 of the Michelson interferometer of the present invention are vertically parallel interference fringes with alternating light and dark patterns of equal thickness.

[0076] like Figure 1 As shown in FIG. 1 , in the Michelson interferometer of the present invention, the liquid crystal device 18 is placed between the beam splitter 17 and the vertical reflector 19. Figure 2 As shown, the liquid crystal device 18 is composed of a transmissive liquid crystal lens 31 and a liquid crystal cell 32. The liquid crystal lens 31 can be a multi-layer film structure. Figure 3 As shown, the middle layer is a liquid crystal layer 40, and the liquid crystal material can be a nematic liquid crystal, such as Cb-5 (4-n-pentyl-4'-cyanobiphenyl, 4-cyano-4-5-alkylbiphenyls). Flanking the liquid crystal layer are a polyimide layer 41, an ITO conductive film layer 42, and a glass layer 43. The liquid crystal layer 40 is approximately 5 microns thick, the polyimide layer 41 is approximately 300 nanometers thick, the ITO conductive film layer 42 is approximately 50 nanometers thick, and the glass layer 43 is approximately 5 mm thick. The ITO (indium tin oxide) conductive film layer is connected to the liquid crystal drive power supply 27 from the side. The liquid crystal cell 32 is a box with upper and lower end faces and is open on all sides. The liquid crystal lens 31 can be installed and removed from the liquid crystal cell 32 through a slot in the upper end face. Four pillars 35 support the upper and lower end faces 33 and 34.

[0077] like Figure 1As shown, the liquid crystal drive power supply 27 is connected to an external computer 26 via a network cable for remote voltage control. By changing the voltage provided by the liquid crystal drive power supply 27, the orientation of the liquid crystal molecules is adjusted, thereby changing the refractive index of the liquid crystal in the direction of light beam propagation. At this time, the overall movement of the vertical parallel interference fringes can be observed on the CCD 25.

[0078] In the Michelson interferometer of the present invention, when in the radiation-generating working state 2, an in-situ test of the refractive index change caused by the liquid crystal radiation effect can be achieved. Figure 1 As shown, the vertical reflector 19 is placed between the liquid crystal device 18 and the radiation source 20. The vertical reflector 19 is an aluminum plate with a thickness of 40 mm. The ranges of an 8 MeV energy electron beam and a 10 MeV proton beam in the aluminum plate are 14.8 mm and 0.5 mm respectively. Therefore, the vertical reflector 19 made of a 40 mm thick aluminum plate can effectively shield, block and absorb the electron and proton beams in the simulation space. At the same time, the aluminum plate has a lower degree of activation after irradiation and has lower radioactivity, which has advantages over other metals in radiation safety. A small hole 30 is opened at an appropriate position on the back of the aluminum plate vertical reflector 19, and the hole diameter can be about 2 mm. The small hole 30 is a non-through hole with a hole depth of 39.9 mm, that is, there is a thin layer of 0.1 mm at the bottom of the small hole. This thin layer ensures that light beam 17 is reflected across the entire surface of vertical reflector 19. It also ensures that, after most of the radiation 21 from radiating device 20 is shielded and absorbed, a small portion can penetrate the thin layer at the bottom of the aperture to form a transmitted particle beam 22 and irradiate liquid crystal device 18. Continuous irradiation by charged particle radiation causes ionization and charging of vertical reflector 19, necessitating grounding to conduct away the charge generated by ionization and accumulated charge.

[0079] In the Michelson interferometer of the present invention, refractive index measurement is performed in state 2 in the following manner: First, a radiation ray 21 with a predetermined fluence rate and energy is obtained by adjusting the beam current of the radiation source 20, and the Michelson interferometer is initially irradiated with the ray 21 having these irradiation parameters. After a period of irradiation, the current fluence is calculated, and the refractive index change Δn is calculated from the interference fringe distortion in the CCD 24. Irradiation is then continued with the ray 21 having these irradiation parameters, and the refractive index change Δn is calculated again when another specific fluence point is reached. After several rounds of irradiation at different fluence points, a curve can be obtained showing how the refractive index change Δn varies with the fluence of charged particles of a certain energy. The energy of the ray 21 is then varied, and a curve showing how the refractive index change Δn varies with the fluence of charged particles of this energy is again obtained. Ultimately, a pattern can be obtained showing how the refractive index change Δn varies with the energy and fluence of the incident charged particles.

[0080] There are two possible sources of error in the irradiation-induced refractive index change of the liquid crystal measured using the Michelson interferometer of the present invention: 1. When the transmitted light ray 22 penetrates the bottom of the aperture 30 of the vertical reflector 19, it causes an ionization effect on the aluminum sheet at the bottom of the aperture, resulting in a change in the reflectivity of the transmitted light beam 17; and 2. The potential combined effect of the light ray 19 scattered by the air and the vertical reflector 19 on other optical components in the Michelson interferometer optical path. These two errors can be evaluated and eliminated by the following scheme: remove the liquid crystal device 18 and obtain interference fringes in the CCD 25 in the non-irradiation state 1 and the irradiation state 2. Comparing the interference fringes in these two states, the distortion ΔD" of the interference fringes in the CCD 25 caused by the irradiation environment acting on the Michelson interferometer components other than the liquid crystal device 18 can be determined. ΔD is calculated as ΔD = ΔD' - ΔD", and ΔD is used to further calculate the refractive index change Δn caused by the high-energy radiation irradiation of the liquid crystal device 18.

[0081] Example 2

[0082] The present invention provides a method for measuring the refractive index change of a liquid crystal optical component using a Michelson interferometer. The method measures the change in the refractive index of the liquid crystal optical component caused by radiation using the Michelson interferometer described above. The method comprises:

[0083] Step S1. Turn off the radiation source 20;

[0084] Step S2. Turn on the laser 9 and CCD 25, adjust the position of the horizontal tilt mirror 16 and the vertical reflector 19 and / or the voltage provided by the liquid crystal drive power supply 27, and obtain interference fringes when the radiation source 20 is turned off through the CCD 25;

[0085] Step S3. Turn on the radiation source 20 and obtain interference fringes when the radiation source 20 is turned on through the CCD 25;

[0086] Step S4. Observe the distortion ΔD' of the interference fringes in steps S2 and S3 through CCD25;

[0087] Step S5 . The computer 26 calculates the change Δn of the refractive index of the irradiated portion of the liquid crystal optical component based on the distortion ΔD′ of the interference fringes.

[0088] Furthermore, the method further comprises:

[0089] Step S6. Remove the liquid crystal device 18, and obtain interference fringes when the radiation source 20 is turned off and when the radiation source 20 is turned on through CCD25 respectively. By comparing the interference fringes in the two states, obtain the distortion ΔD" of the interference fringes in CCD25 caused by the irradiation environment acting on other components in the Michelson interferometer except the liquid crystal device 18 when the liquid crystal device 18 is not present, and calculate the distortion difference ΔD = ΔD'-ΔD", and use ΔD to further correct Δn.

[0090] The present invention places a liquid crystal device between a beam splitter and a reflector in one optical path of a Michelson interferometer. A radiation device is placed behind the reflector. The size and thickness of the reflector are designed to shield ionizing radiation emitted by the radiation device. Non-penetrating apertures are also provided in the reflector to allow the ionizing radiation to penetrate through the apertures and locally irradiate the liquid crystal device. By comparing the distortion of the Michelson interference fringes with and without ionizing radiation irradiation, the change in the refractive index of the liquid crystal component caused by ionizing radiation irradiation can be determined in real time.

[0091] From the above detailed description of the present invention, it can be seen that the present invention proposes a Michelson interferometer that can perform in-situ testing of the irradiation effect on liquid crystals. Ionizing radiation is transmitted through the bottom of a small hole provided in an aluminum reflector to locally irradiate the liquid crystal. By comparing the distortion of the interference fringes obtained by the Michelson interferometer with and without irradiation, the change in the refractive index of the liquid crystal caused by the irradiation effect is obtained.

[0092] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and are intended to be encompassed by the claims of the present invention.

Claims

1. A Michelson interferometer, for measuring changes in the refractive index of a liquid crystal optical component affected by radiation, comprising: A beam splitter (14), a horizontal tilt reflector (16) and a vertical reflector (19), wherein the Michelson interferometer further comprises: a liquid crystal device (18) and a radiation source (20); wherein, The back of the vertical reflector (19) is provided with a non-through hole (30); a thin layer of a set thickness is provided at the bottom of the non-through hole (30); the liquid crystal device (18) is placed between the beam splitter (14) and the vertical reflector (19); the liquid crystal optical component is placed in the liquid crystal device (18); the radiation source (20) is placed on the back of the vertical reflector (19); The beam splitter (14) is used to split the parallel light beam incident on the beam splitter into two light beams, one light beam is incident on the horizontal tilt reflector (16), and the other light beam passes through the liquid crystal device (18) and is incident on the vertical reflector (19); The horizontally tilted reflector (16) is used to reflect the incident light beam to the beam splitter (14); the light beam reflected to the beam splitter (14) is transmitted through the beam splitter (14); The vertical reflector (19) is used to reflect the incident light beam; the light beam reflected by the vertical reflector (19) passes through the liquid crystal device (18) and is then reflected by the beam splitter (14); The light beam transmitted by the beam splitter (14) and the light beam reflected by the beam splitter (14) converge at the beam splitter (14) to form an interference light beam; The radiation source (20) is used to generate radiation rays; the radiation rays penetrate the non-penetrating aperture (30) and irradiate a part of the liquid crystal optical component in the liquid crystal device (18).

2. The Michelson interferometer according to claim 1, wherein The Michelson interferometer further comprises: a laser (9), a 45-degree angle reflector (12) and a collimating beam expander (13); wherein, The laser (9) is used to emit a linearly polarized laser beam, which is incident on a 45-degree angle reflector (12); The 45-degree angle reflector (12) is used to reflect the incident light beam so that the reflected light beam is perpendicular to the light beam emitted by the laser (9) and is incident on the collimating beam expander (13); The collimating beam expander (13) is used to expand the incident light beam into a parallel light beam, and the spot diameter of the parallel light beam is larger than the diameter of the non-penetrating pinhole.

3. The Michelson interferometer according to claim 2, wherein: The Michelson interferometer further comprises: a focusing lens (24), a CCD (25), a liquid crystal driving power supply (27) and a computer (26); wherein, The condenser lens (24) is used to converge the interference light beam; The CCD (25) is used to process the converged interference light beam to obtain interference fringes, including interference fringes when the radiation source (20) is turned on and interference fringes when the radiation source (20) is turned off; and is also used to obtain the distortion amount of the interference fringes based on the interference fringes when the radiation source (20) is turned on and the interference fringes when the radiation source (20) is turned off; The liquid crystal driving power supply (27) is used to provide voltage to the liquid crystal optical component and adjust the orientation of molecules in the liquid crystal optical component by providing a changed voltage, thereby changing the refractive index of the liquid crystal in the propagation direction of the light beam; The computer (26) is used to calculate the change in the refractive index of the irradiated portion of the liquid crystal optical component based on the distortion of the interference fringes; and is also used to control the liquid crystal driving power supply (27).

4. The Michelson interferometer according to claim 3, wherein The vertical reflector (19) is grounded; the material of the vertical reflector (19) is an aluminum plate; and the front surface of the vertical reflector (19) is a polished and smooth mirror surface.

5. The Michelson interferometer according to claim 3, wherein: The distortion amount of the interference fringes is the change in the width and position of the interference fringes.

6. The Michelson interferometer according to claim 3, wherein: The radiation source (20) is an electron gun, a proton gun, an electron accelerator or a proton accelerator.

7. The Michelson interferometer according to claim 3, wherein The thickness of the thin layer at the bottom of the non-penetrating aperture should be able to ensure the transmission of radiation.

8. The Michelson interferometer according to claim 3, wherein The liquid crystal device (18) comprises a liquid crystal box; the liquid crystal box is a box body with upper and lower end surfaces and open on all sides, and is used for loading and unloading liquid crystal optical components.

9. A method for measuring the refractive index change of a liquid crystal optical component using a Michelson interferometer, wherein the method comprises measuring the refractive index change of a liquid crystal optical component caused by radiation using the Michelson interferometer according to any one of claims 3 to 8, wherein: The method comprises: Step S1. Turn off the radiation source (20); Step S2. Turn on the laser (9) and the CCD (25), adjust the position of the horizontal tilt mirror (16) and the vertical mirror (19) and / or the voltage provided by the liquid crystal drive power supply (27), and obtain the interference fringes when the radiation source (20) is turned off through the CCD (25); Step S3. Turning on the radiation source (20), and obtaining interference fringes when the radiation source (20) is turned on through the CCD (25); Step S4. Observe the distortion ΔD' of the interference fringes in steps S2 and S3 through the CCD (25); Step S5. The computer (26) calculates the change in the refractive index Δn of the irradiated portion of the liquid crystal optical component based on the distortion ΔD' of the interference fringes.

10. The method for measuring the refractive index change of a liquid crystal optical component using a Michelson interferometer according to claim 9, characterized in that: The method further comprises: Step S6. The liquid crystal device (18) is removed, and interference fringes are obtained through the CCD (25) when the radiation source (20) is turned off and when the radiation source (20) is turned on. By comparing the interference fringes in the two states, the distortion ΔD" of the interference fringes in the CCD (25) caused by the irradiation environment acting on other components of the Michelson interferometer except the liquid crystal device (18) when the liquid crystal device (18) is not present is obtained, and the distortion difference ΔD = ΔD'-ΔD" is calculated, and Δn is further corrected using ΔD.

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