Polarization ultrafast spectrum testing system and method

Abstract

The invention provides a polarization ultrafast spectrum test system and method. The polarization ultrafast spectrum testing system comprises a laser generating device, a pump light polarization control module, a pump light circular polarization control module, a detection light polarization control module, a detection light circular polarization control module, a focusing module, a sample placing platform, a polarization beam splitting module, a first spectrum detector and a second spectrum detector. The pump light polarization control module and the pump light circular polarization control module are alternatively arranged at the pump light output end of the laser generating device; the focusing module is used for focusing the pump light and the probe light on one side of a sample to be detected; and the polarization light splitting module is used for splitting the detection light transmitted from the other side of the to-be-detected sample into two beams of linearly polarized light of which the polarization directions are vertical to each other. According to the invention, detection light signals in different polarization states can be synchronously acquired in one experiment, and the method has the advantages of high test efficiency, low error and strong compatibility.

Description

Technical Field

[0001] The present invention relates to the field of ultrafast optical technologies, and particularly to a polarization ultrafast spectroscopy testing system and method. Background Art

[0002] Ultrafast spectroscopy technologies are widely used to study the ultrafast kinetic processes of the excited states of systems, and can provide rich spectral features and ultrafast time kinetic information in the time and frequency dimensions. Currently, the most widely applied ultrafast spectroscopy technology is transient absorption (also known as pump-probe) spectroscopy technology. This technology uses laser pulses generated by femtosecond lasers (usually with pulse widths of several hundred femtoseconds or even shorter), and by precisely controlling the time delay between the pump light and the probe light, captures the transient states of molecules, carriers or excitons, as well as processes such as energy transfer and charge transfer. As one of the most mature methods in ultrafast spectroscopy technologies, transient absorption spectroscopy technology has been widely applied in fields such as chemical reaction kinetics, solar cells, photocatalysis, biomolecular dynamics, and semiconductor materials.

[0003] In recent years, based on traditional ultrafast spectroscopy testing technologies, researchers have gradually started to pay attention to the application of polarization ultrafast spectroscopy testing technologies in related research, especially in the study of the ultrafast dynamics of excited states in chiral molecules and anisotropic materials. Polarization-dependent ultrafast spectroscopy testing technologies mainly include linearly polarized ultrafast spectroscopy testing and circularly polarized ultrafast spectroscopy testing. Among them, linearly polarized ultrafast spectroscopy testing is to study the transient spectral changes of materials in a specific linear polarization direction by regulating the linear polarization states of the pump light and the probe light, and then to reveal the optical properties caused by the molecular orientation and anisotropy of the crystal structure of the sample; while circularly polarized ultrafast spectroscopy testing uses left-handed and right-handed circularly polarized lights to study the absorption differences of the sample for different circularly polarized lights, and reveals the electronic transition characteristics of chiral materials and their relationships with molecular or crystal configurations.

[0004] Currently, traditional polarization ultrafast spectroscopy testing systems mainly measure ultrafast spectroscopy data in different polarization directions by manually adjusting the angle of the glass slide. This method has the following obvious deficiencies:

[0005] 1. Problem of separate tests: To obtain ultrafast spectroscopy data in different polarization detection states, it is often necessary to conduct two separate tests (such as measuring horizontal linear polarization once and vertical linear polarization once; or measuring left-handed circular polarization once and right-handed circular polarization once). This not only prolongs the test time, but also may cause signal attenuation due to the sample being irradiated by the excitation light for a long time, thereby introducing additional errors.

[0006] 2. Optical path coupling fluctuations: Fluctuations in laser power and changes in the spatial coupling of the pump light and the probe light will cause systematic differences in data between separate tests, thereby affecting the accuracy and comparability of ultrafast spectroscopy data in different polarization states.

[0007] A transient polarization absorption spectroscopy measurement method and a laser flash photolysis instrument system for implementing the method, as disclosed in a Chinese invention patent with the publication number CN105910995A. The technical solution disclosed in this patent is a typical representative of traditional polarization ultrafast spectroscopy testing techniques. In this patent, different polarization state measurements are mainly achieved by manually adjusting the angle of a glass slide, which has problems such as cumbersome operation, long testing cycle, laser power fluctuation, and systematic errors introduced by changes in the spatial coupling of the pump light and the probe light, thus restricting the wide application of this technology. Summary of the Invention

[0008] The object of the present invention is to provide a polarization ultrafast spectroscopy testing system and method for defects in the prior art, which can simultaneously collect ultrafast spectral signals in different polarization states through only one test respectively when performing linear polarization ultrafast spectroscopy testing and circular polarization ultrafast spectroscopy testing, improving the efficiency of polarization ultrafast spectroscopy testing, as well as the accuracy and reproducibility of test data.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A polarization ultrafast spectroscopy testing system for performing linear polarization ultrafast spectroscopy testing and circular polarization ultrafast spectroscopy testing, including a laser generation device, a pump light linear polarization control module, a pump light circular polarization control module, a probe light linear polarization control module, a probe light circular polarization control module, a focusing module, a sample placement platform, a polarization beam splitting module, a first spectral detector, and a second spectral detector;

[0011] The laser generation device is used to generate and output pump light and probe light;

[0012] The pump light linear polarization control module and the pump light circular polarization control module are alternatively arranged at the pump light output end of the laser generation device for changing the polarization state of the pump light; wherein, when performing linear polarization ultrafast spectroscopy testing, the pump light linear polarization control module is arranged at the pump light output end of the laser generation device for converting the pump light into linearly polarized light in a specific polarization direction; when performing circular polarization ultrafast spectroscopy testing, the pump light circular polarization control module is arranged at the pump light output end of the laser generation device for converting the pump light into circularly polarized light in a specific polarization direction;

[0013] The probe light linear polarization control module is arranged at the probe light output end of the laser generation device for converting the probe light into linearly polarized light in a specific polarization direction;

[0014] The focusing module is arranged on one side of the sample placement platform for focusing the polarization-processed pump light and probe light on one side of the sample to be measured on the sample placement platform;

[0015] The polarization beam splitting module is arranged on the other side of the sample placement platform and is used to split the detection light transmitted through the other side of the sample to be measured into two linearly polarized lights with perpendicular polarization directions;

[0016] The first spectral detector and the second spectral detector are arranged on the output side of the polarization beam splitting module and are respectively used to collect the two linearly polarized lights with perpendicular polarization directions output by the polarization beam splitting module for spectral analysis;

[0017] The detection light circular polarization control module is used to be arranged between the sample placement platform and the polarization beam splitting module during circular polarization ultrafast spectroscopy testing to convert the detection light transmitted through the other side of the sample to be measured into circularly polarized light.

[0018] Further, during linear polarization ultrafast spectroscopy testing, the detection light linear polarization control module converts the detection light into linearly polarized light with a polarization direction at a 45-degree angle to the horizontal plane; during circular polarization ultrafast spectroscopy testing, the detection light linear polarization control module converts the detection light into linearly polarized light with a horizontal polarization direction.

[0019] Further, the focusing module is composed of an optical element with a focusing function and a reflecting mirror and is used to focus the pump light and the detection light on the sample to be measured at different angles, so that the pump light and the detection light transmitted through the other side of the sample to be measured do not overlap;

[0020] A light blocking plate is arranged on the other side of the sample placement platform, and the light blocking plate is used to block the pump light transmitted through the other side of the sample to be measured.

[0021] Further, the laser generating device includes a laser, a beam splitter, a pump light generating module, an optical delay line, and a detection light generating module;

[0022] The laser is used to generate ultrashort pulse laser;

[0023] The beam splitter is arranged at the output end of the laser and is used to split the ultrashort pulse laser output by the laser into transmitted light and reflected light with a certain light intensity ratio; among them, the transmitted light passing through the beam splitter is input to the pump light generating module, and the reflected light after being reflected and turned by the beam splitter is input to the detection light generating module through the optical delay line;

[0024] The pump light generating module is an optical parametric amplifier or a nonlinear crystal frequency doubler and is used to process the transmitted light to generate tunable-wavelength pump light;

[0025] The detection light generating module is a nonlinear crystal and is used to process the reflected light to generate white light as the detection light;

[0026] The optical delay line is used to optically delay the reflected light to change the optical path difference between the pump light and the probe light reaching the sample to be measured, thereby achieving time resolution.

[0027] Further, the optical delay line includes an electric translation stage and a hollow retroreflector disposed on the electric translation stage; the electric translation stage is controlled by software programming.

[0028] Further, a chopper or an electronic shutter is provided in the pump light generation module for pulse modulation of the pump light to generate pump light modulated at time intervals.

[0029] Further, both the pump light linear polarization control module and the probe light linear polarization control module are composed of a linear polarizer and a half-wave plate; by adjusting the angle of the half-wave plate therein, the polarization direction of the linearly polarized light is adjusted;

[0030] The pump light circular polarization control module and the probe light circular polarization control module are quarter-wave plates or polymer circular polarizers; by adjusting the angle of the quarter-wave plate or polymer circular polarizer, the linearly polarized light is converted into left-handed circularly polarized light or right-handed circularly polarized light.

[0031] Further, the polarization beam splitting module is a Wollaston prism, Rochon prism, polarization plate beam splitter or polarization beam splitter;

[0032] The first spectral detector and the second spectral detector are fiber optic spectrometers, photodiode arrays, photomultiplier tubes, balanced photodetectors, CCD cameras or CMOS cameras.

[0033] A polarization ultrafast spectroscopy test method is implemented based on the above-described polarization ultrafast spectroscopy test system. The polarization ultrafast spectroscopy test method performs linear polarization ultrafast spectroscopy test through the following steps:

[0034] S101. Place and fix the sample to be measured on the sample placement platform;

[0035] S102. Set the pump light linear polarization control module at the pump light output end of the laser generating device, and remove the pump light circular polarization control module and the probe light circular polarization control module from the system;

[0036] S103. By adjusting the pump light linear polarization control module, convert the pump light into linearly polarized light with the polarization direction to be measured; by adjusting the probe light linear polarization control module, convert the probe light into linearly polarized light with the polarization direction at an angle of 45 degrees to the horizontal plane;

[0037] S104. Focus the polarization-processed pump light and probe light on one side of the sample to be measured through the focusing module;

[0038] S105. On the other side of the sample to be measured, collect the probe light transmitted through the other side of the sample to be measured by means of a polarization beam splitter module, and decompose it into horizontally polarized light and vertically polarized light;

[0039] S106. Respectively collect the horizontally polarized light and vertically polarized light output by the polarization beam splitter module through a first spectral detector and a second spectral detector, and analyze the transient absorption spectra of the horizontally polarized light and the vertically polarized light through a program.

[0040] Further, the polarization ultrafast spectroscopy test method performs circular polarization ultrafast spectroscopy test through the following steps:

[0041] S201. Place and fix the sample to be measured on the sample placement platform;

[0042] S202. Set the pump light circular polarization control module at the pump light output end of the laser generating device, set the probe light circular polarization control module between the sample placement platform and the polarization beam splitter module, and remove the pump light linear polarization control module from the system;

[0043] S203. By adjusting the pump light circular polarization control module, convert the pump light into left-handed circularly polarized light or right-handed circularly polarized light; by adjusting the probe light polarization control module, convert the probe light into linearly polarized light with a horizontal polarization direction;

[0044] S204. Focus the polarization-processed pump light and probe light on one side of the sample to be measured through a focusing module;

[0045] S205. On the other side of the sample to be measured, convert the probe light transmitted through the other side of the sample to be measured into circularly polarized light by means of the probe light circular polarization control module;

[0046] S206. Collect the circularly polarized light output by the probe light circular polarization control module through the polarization beam splitter module, and decompose it into horizontally polarized light and vertically polarized light;

[0047] S207. Respectively collect the horizontally polarized light and vertically polarized light output by the polarization beam splitter module through a first spectral detector and a second spectral detector, and analyze the transient absorption spectra of the horizontally polarized light and the vertically polarized light through a program; the transient absorption spectra of the horizontally polarized light and the vertically polarized light respectively represent the transient absorption spectra when left-handed circularly polarized light and right-handed circularly polarized light are used as the probe light.

[0048] A polarization ultrafast spectroscopy test system and method provided by the present invention decompose the probe light into two linearly polarized lights with perpendicular polarization directions through a polarization beam splitting module. When performing linear polarization ultrafast spectroscopy tests, it can achieve simultaneous acquisition of ultrafast spectral data in the horizontal and vertical linear polarization directions in a single experiment. Further, when performing circular polarization ultrafast spectroscopy tests, by adding a probe light circular polarization control module in front of the polarization beam splitting module, it can achieve simultaneous acquisition of ultrafast spectral data in the left-handed and right-handed circular polarization directions in a single experiment.

[0049] The present invention can synchronously collect probe light signals in different polarization states in a single experiment. Compared with the traditional measurement method in multiple steps, it significantly shortens the test time, greatly reduces the requirements for the light stability of materials, and improves the test efficiency of polarization ultrafast spectroscopy. At the same time, the measurement method of the present invention effectively eliminates the systematic errors introduced by laser power fluctuations and optical path spatial coupling changes, improving the accuracy and reproducibility of test data. In addition, the present invention can realize the switching between linear polarization and circular polarization working modes by simply switching the optical paths of the pump light linear polarization control module, the pump light circular polarization control module, and the probe light circular polarization control module, and simply adjusting the probe light linear polarization control module, which can flexibly meet various ultrafast spectroscopy test requirements and has strong compatibility.

[0050] In summary, compared with the prior art, a polarization ultrafast spectroscopy test system and method provided by the present invention have the advantages of high test efficiency, low error, and strong compatibility. Description of the Drawings

[0051] Figure 1 is a schematic structural diagram of a polarization ultrafast spectroscopy test system provided by an embodiment of the present invention when performing linear polarization ultrafast spectroscopy tests.

[0052] Figure 2 is a schematic structural diagram of a polarization ultrafast spectroscopy test system provided by an embodiment of the present invention when performing circular polarization ultrafast spectroscopy tests. Detailed Embodiments

[0053] The technical solutions of the present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0054] A polarization ultrafast spectroscopy test system provided by an embodiment of the present invention can simultaneously collect ultrafast spectral signals in different polarization states through only one test respectively when performing linear polarization ultrafast spectroscopy tests and circular polarization ultrafast spectroscopy tests.

[0055] Such as Figure 1 and Figure 2As shown in the figure, the polarization ultrafast spectroscopy test system includes a laser generation device, a pump light polarization control module, a pump light circular polarization control module, a probe light polarization control module, a probe light circular polarization control module, a focusing module, a sample placement platform, a polarization beam splitting module, a first spectroscopic detector, and a second spectroscopic detector.

[0056] Specifically, the laser generation device is used to generate and output pump light and probe light.

[0057] The pump light polarization control module and the pump light circular polarization control module are alternatively arranged at the pump light output end of the laser generation device to change the polarization state of the pump light. Among them, when performing linear polarization ultrafast spectroscopy tests, the pump light polarization control module is arranged at the pump light output end of the laser generation device to convert the pump light into linearly polarized light with a specific polarization direction. When performing circular polarization ultrafast spectroscopy tests, the pump light circular polarization control module is arranged at the pump light output end of the laser generation device to convert the pump light into circularly polarized light with a specific polarization direction.

[0058] The probe light polarization control module is arranged at the probe light output end of the laser generation device to convert the probe light into linearly polarized light with a specific polarization direction. Among them, when performing linear polarization ultrafast spectroscopy tests, the probe light polarization control module converts the probe light into linearly polarized light with a polarization direction at a 45-degree angle to the horizontal plane. When performing circular polarization ultrafast spectroscopy tests, the probe light polarization control module converts the probe light into linearly polarized light with a horizontal polarization direction.

[0059] The focusing module is arranged on one side of the sample placement platform to focus the polarization-processed pump light and probe light on one side of the sample to be tested on the sample placement platform.

[0060] The polarization beam splitting module is arranged on the other side of the sample placement platform to split the probe light transmitted through the other side of the sample to be tested into two linearly polarized lights with mutually perpendicular polarization directions.

[0061] The first spectroscopic detector and the second spectroscopic detector are arranged on the output side of the polarization beam splitting module, and are respectively used to collect the two linearly polarized lights with mutually perpendicular polarization directions output by the polarization beam splitting module for spectral analysis.

[0062] The probe light circular polarization control module is used to be arranged between the sample placement platform and the polarization beam splitting module during circular polarization ultrafast spectroscopy tests to convert the probe light transmitted through the other side of the sample to be tested into circularly polarized light.

[0063] Furthermore, the laser generation device includes a laser, a beam splitter, a pump light generation module, an optical delay line, and a probe light generation module.

[0064] The laser is used to generate ultrashort pulsed laser light;

[0065] The beam splitter is arranged at the output end of the laser, and is used for splitting the ultrashort pulsed laser light output by the laser into transmitted light and reflected light with a certain light intensity ratio; wherein, the relatively stronger transmitted light is used to generate pump light, and the relatively weaker reflected light is used to generate probe light; the transmitted light passing through the beam splitter is input into the pump light generation module, and the reflected light reflected and redirected by the beam splitter is input into the probe light generation module through an optical delay line;

[0066] The pump light generation module is an optical parametric amplifier or a non-linear crystal frequency doubler, and is used for processing the transmitted light to generate tunable-wavelength pump light; as an improvement, a chopper or an electronic shutter is arranged in the pump light generation module, and is used for pulse modulating the pump light to generate pump light modulated at intervals in time;

[0067] The probe light generation module is a non-linear crystal (such as a sapphire wafer or a calcium fluoride wafer, etc.), and is used for processing the reflected light to generate white light as probe light;

[0068] The optical delay line is used for performing optical delay processing on the reflected light to change the optical path difference between the pump light and the probe light reaching the sample to be measured, so as to achieve time resolution. In this embodiment, the optical delay line includes an electric translation stage and a hollow retroreflector arranged on the electric translation stage; the electric translation stage is controlled by software programming to flexibly adjust the optical path of the probe light reaching the sample to be measured.

[0069] Further, the focusing module is composed of optical elements with focusing functions such as lenses, concave mirrors or parabolic mirrors and reflectors, and is used for focusing the pump light and the probe light on the sample to be measured at different angles, so that the pump light and the probe light transmitted out from the other side of the sample to be measured do not overlap with each other, so that the pump light and the probe light can be effectively separated to separately collect the probe light transmitted out. Correspondingly, a light blocking plate is arranged on the other side of the sample placement platform, and the light blocking plate is used for blocking the pump light transmitted out from the other side of the sample to be measured.

[0070] Further, both the pump light linear polarization control module and the probe light linear polarization control module are composed of a combination of a linear polarizer and a half-wave plate; by adjusting the angle of the half-wave plate therein, the polarization direction of the linearly polarized light can be adjusted;

[0071] The pump light circular polarization control module and the probe light circular polarization control module are quarter-wave plates or polymer circular polarizers; by adjusting the angle (±45°) of the quarter-wave plate or the polymer circular polarizer, the linearly polarized light can be converted into left-handed circularly polarized light or right-handed circularly polarized light.

[0072] The polarization beam splitting module is an optical element with polarization beam splitting function, such as Wollaston prism, Rochon prism, polarization plate beam splitter or polarization beam splitter.

[0073] The first spectral detector and the second spectral detector are optical instruments with spectral resolution function, such as fiber spectrometer, photodiode array, photomultiplier tube, balanced photodetector, CCD camera or CMOS camera, which are key important devices for signal conversion and measurement.

[0074] An embodiment of the present invention also provides a polarization ultrafast spectroscopy test method, which is implemented based on the above-mentioned polarization ultrafast spectroscopy test system.

[0075] Combined with Figure 1 As shown, in the polarization ultrafast spectroscopy test method, the linearly polarized ultrafast spectroscopy test is carried out through the following steps:

[0076] S101. Place and fix the sample to be tested on the sample placement platform;

[0077] S102. Set the pump light polarization control module at the pump light output end of the laser generating device, and remove the pump light circular polarization control module and the probe light circular polarization control module from the system;

[0078] S103. By adjusting the angle of the half-wave plate in the pump light polarization control module, convert the pump light into linearly polarized light with the polarization direction to be measured (such as horizontal or vertical); by adjusting the angle of the half-wave plate in the probe light polarization control module, convert the probe light into linearly polarized light with the polarization direction at 45 degrees to the horizontal plane;

[0079] S104. Focus the polarized pump light and probe light on one side of the sample to be tested through the focusing module;

[0080] S105. On the other side of the sample to be tested, collect the probe light transmitted through the other side of the sample to be tested through the polarization beam splitting module, and decompose it into horizontally polarized light and vertically polarized light; at the same time, block the transmitted pump light through the light baffle;

[0081] S106. Collect the horizontally polarized light and vertically polarized light output by the polarization beam splitting module through the first spectral detector and the second spectral detector respectively, and analyze the transient absorption spectra of the horizontally polarized light and the vertically polarized light through the program, so as to simultaneously collect the ultrafast spectral data in the horizontal and vertical polarization directions in one experiment.

[0082] Combined with Figure 2 As shown, in the polarization ultrafast spectroscopy test method, the circularly polarized ultrafast spectroscopy test is carried out through the following steps:

[0083] S201. Place and fix the sample to be measured on the sample placement platform;

[0084] S202. Set the pump light circular polarization control module at the pump light output end of the laser generating device, set the probe light circular polarization control module between the sample placement platform and the polarization beam splitting module, and remove the pump light linear polarization control module from the system;

[0085] S203. By adjusting the angle of the quarter-wave plate or polymer circular polarizer in the pump light circular polarization control module, convert the pump light into left-handed circularly polarized light or right-handed circularly polarized light; by adjusting the angle of the half-wave plate in the probe light linear polarization control module, convert the probe light into linearly polarized light with a horizontal polarization direction;

[0086] S204. Focus the polarization-processed pump light and probe light on one side of the sample to be measured through the focusing module;

[0087] S205. On the other side of the sample to be measured, convert the probe light transmitted through the other side of the sample to be measured into circularly polarized light through the probe light circular polarization control module; at the same time, block the transmitted pump light with a light baffle;

[0088] S206. Collect the circularly polarized light output by the probe light circular polarization control module through the polarization beam splitting module, and decompose it into horizontally polarized light and vertically polarized light;

[0089] S207. Collect the horizontally polarized light and vertically polarized light output by the polarization beam splitting module through the first spectral detector and the second spectral detector respectively, and analyze the transient absorption spectra of the horizontally polarized light and the vertically polarized light through a program; wherein, the transient absorption spectra of the horizontally polarized light and the vertically polarized light respectively represent the transient absorption spectra when using left-handed circularly polarized light and right-handed circularly polarized light as the probe light, so as to simultaneously collect ultrafast spectral data in the left-handed and right-handed circular polarization directions in one experiment.

[0090] A polarization ultrafast spectroscopy test system and method provided by the present invention decompose the probe light into two linearly polarized lights with perpendicular polarization directions through the polarization beam splitting module. When performing linearly polarized ultrafast spectroscopy tests, it is possible to simultaneously collect ultrafast spectral data in the horizontal and vertical linear polarization directions in one experiment. Further, when performing circularly polarized ultrafast spectroscopy tests, by adding a probe light circular polarization control module in front of the polarization beam splitting module, it is possible to simultaneously collect ultrafast spectral data in the left-handed and right-handed circular polarization directions in one experiment.

[0091] The present invention can synchronously collect the probe light signals in different polarization states in one experiment. Compared with the traditional measurement method in multiple times, the test time is significantly shortened, the requirement for the optical stability of the material is greatly reduced, and the test efficiency of the polarization ultrafast spectroscopy is improved. At the same time, the measurement method of the present invention effectively eliminates the systematic errors introduced by the laser power fluctuation and the change of the optical path spatial coupling, and improves the accuracy and reproducibility of the test data. In addition, by simply switching the optical paths of the pump light polarization control module, the pump light circular polarization control module and the probe light circular polarization control module, and simply adjusting the probe light polarization control module, the present invention can realize the switching between the linear polarization and circular polarization working modes, can flexibly meet various ultrafast spectroscopy test requirements, and has extremely strong compatibility.

[0092] In summary, compared with the prior art, a polarization ultrafast spectroscopy test system and method provided by the present invention have the advantages of high test efficiency, low error and strong compatibility.

[0093] The above embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A polarization ultrafast spectroscopy test system for performing linear polarization ultrafast spectroscopy tests and circular polarization ultrafast spectroscopy tests, characterized in that, It includes a laser generating device, a pump light polarization control module, a pump light circular polarization control module, a probe light polarization control module, a probe light circular polarization control module, a focusing module, a sample placement platform, a polarization beam splitter module, a first spectral detector, and a second spectral detector; The laser generating device is used to generate and output pump light and probe light; The pump light polarization control module and the pump light circular polarization control module are alternatively arranged at the pump light output end of the laser generating device to change the polarization state of the pump light. Among them, when performing linear polarization ultrafast spectroscopy tests, the pump light polarization control module is arranged at the pump light output end of the laser generating device to convert the pump light into linearly polarized light with a specific polarization direction. When performing circular polarization ultrafast spectroscopy tests, the pump light circular polarization control module is arranged at the pump light output end of the laser generating device to convert the pump light into circularly polarized light with a specific polarization direction; The probe light polarization control module is arranged at the probe light output end of the laser generating device to convert the probe light into linearly polarized light with a specific polarization direction; The focusing module is arranged on one side of the sample placement platform to focus the polarized pump light and probe light on one side of the sample to be measured on the sample placement platform; The polarization beam splitter module is arranged on the other side of the sample placement platform to decompose the probe light transmitted through the other side of the sample to be measured into two linearly polarized lights with perpendicular polarization directions; The first spectral detector and the second spectral detector are arranged on the output side of the polarization beam splitter module and are respectively used to collect the two linearly polarized lights with perpendicular polarization directions output by the polarization beam splitter module for spectral analysis; The probe light circular polarization control module is used to be arranged between the sample placement platform and the polarization beam splitter module during circular polarization ultrafast spectroscopy tests to convert the probe light transmitted through the other side of the sample to be measured into circularly polarized light.

2. The multimodal ultrafast optical microscopy imaging system according to claim 1, wherein During linear polarization ultrafast spectroscopy tests, the probe light polarization control module converts the probe light into linearly polarized light with an angle of 45 degrees with the horizontal plane. During circular polarization ultrafast spectroscopy tests, the probe light polarization control module converts the probe light into linearly polarized light with a horizontal polarization direction.

3. The multimodal ultrafast optical microscopy imaging system according to claim 2, wherein The focusing module is composed of an optical element with a focusing function and a mirror, and is used to focus the pump light and the probe light on the sample to be measured at different angles, so that the pump light and the probe light transmitted through the other side of the sample to be measured do not overlap; A light blocking plate is arranged on the other side of the sample placement platform, and the light blocking plate is used to block the pump light transmitted through the other side of the sample to be measured.

4. The polarization ultrafast spectroscopy test system according to claim 2, wherein The laser generating device includes a laser, a beam splitter, a pump light generating module, an optical delay line, and a probe light generating module; The laser is used to generate ultrashort pulse laser; The beam splitter is arranged at the output end of the laser and is used to split the ultrashort pulse laser output by the laser into transmitted light and reflected light with a certain light intensity ratio. Among them, the transmitted light passing through the beam splitter is input to the pump light generating module, and the reflected light reflected and redirected by the beam splitter is input to the probe light generating module through the optical delay line; The pump light generation module is an optical parametric amplifier or a non-linear crystal frequency doubler, which is used to process the transmitted light to generate a pump light with tunable wavelength; The probe light generation module is a non-linear crystal, which is used to process the reflected light to generate white light as the probe light; The optical delay line is used to perform optical delay processing on the reflected light to change the optical path difference between the pump light and the probe light reaching the sample to be measured, so as to achieve time resolution.

5. The multimodal ultrafast optical microscopy imaging system according to claim 4, wherein The optical delay line includes an electric translation stage and a hollow retroreflector arranged on the electric translation stage; the electric translation stage is controlled by software programming.

6. The multimodal ultrafast optical microscopy imaging system according to claim 4, wherein A chopper or an electronic shutter is provided in the pump light generation module, which is used to perform pulse modulation on the pump light to generate a pump light with interval modulation in time.

7. The multimodal ultrafast optical microscopy imaging system according to claim 2, wherein Both the pump light linear polarization control module and the probe light linear polarization control module are composed of a linear polarizer and a half-wave plate; by adjusting the angle of the half-wave plate therein, the polarization direction of the linearly polarized light is adjusted; The pump light circular polarization control module and the probe light circular polarization control module are quarter-wave plates or polymer circular polarizers; by adjusting the angle of the quarter-wave plate or polymer circular polarizer, the linearly polarized light is converted into left-handed circularly polarized light or right-handed circularly polarized light.

8. The multimodal ultrafast optical microscopy imaging system according to claim 7, wherein, The polarization beam splitting module is a Wollaston prism, Rochon prism, polarization plate beam splitter or polarization beam splitter; The first spectral detector and the second spectral detector are fiber optic spectrometers, photodiode arrays, photomultiplier tubes, balanced photodetectors, CCD cameras or CMOS cameras.

9. A polarization ultrafast spectroscopy testing method, implemented based on the polarization ultrafast spectroscopy testing system according to any one of claims 1 to 8, characterized in that The polarization ultrafast spectroscopy test method performs linear polarization ultrafast spectroscopy test through the following steps: S101. Place and fix the sample to be measured on the sample placement platform; S102. Set the pump light linear polarization control module at the pump light output end of the laser generation device, and remove the pump light circular polarization control module and the probe light circular polarization control module from the system; S103. By adjusting the pump light linear polarization control module, convert the pump light into linearly polarized light with the polarization direction to be measured; by adjusting the probe light linear polarization control module, convert the probe light into linearly polarized light with the polarization direction at an angle of 45 degrees to the horizontal plane; S104. Focus the polarized pump light and probe light on one side of the sample to be measured through the focusing module; S105. On the other side of the sample to be measured, collect the probe light transmitted through the other side of the sample to be measured through the polarization beam splitting module, and decompose it into horizontally polarized light and vertically polarized light; S106. Collect the horizontally polarized light and vertically polarized light output by the polarization beam splitting module through the first spectral detector and the second spectral detector respectively, and analyze the transient absorption spectra of the horizontally polarized light and the vertically polarized light through the program.

10. The polarization ultrafast spectroscopy test method according to claim 9, wherein The polarization ultrafast spectroscopy test method performs circular polarization ultrafast spectroscopy test through the following steps: S201. Place and fix the sample to be measured on the sample placement platform; S202. Set the pump light circular polarization control module at the pump light output end of the laser generation device, set the probe light circular polarization control module between the sample placement platform and the polarization beam splitting module, and remove the pump light linear polarization control module from the system; S203. Convert the pump light into left-handed circularly polarized light or right-handed circularly polarized light by adjusting the pump light circular polarization control module; convert the probe light into linearly polarized light with a horizontal polarization direction by adjusting the probe light polarization control module. S204. Focus the polarization-processed pump light and probe light on one side of the sample to be measured through the focusing module. S205. On the other side of the sample to be measured, convert the probe light transmitted through the other side of the sample to be measured into circularly polarized light by the probe light circular polarization control module. S206. Collect the circularly polarized light output by the probe light circular polarization control module through the polarization beam splitter module and decompose it into horizontally polarized light and vertically polarized light. S207. Collect the horizontally polarized light and vertically polarized light output by the polarization beam splitter module through the first spectral detector and the second spectral detector respectively, and analyze the transient absorption spectra of the horizontally polarized light and the vertically polarized light through a program; the transient absorption spectra of the horizontally polarized light and the vertically polarized light respectively represent the transient absorption spectra when using left-handed circularly polarized light and right-handed circularly polarized light as the probe light.

Images