Transient absorption spectrum measurement system, method and device for polarized light

Abstract

The invention discloses a transient absorption spectrum measurement system, method and device for polarized light, and relates to the technical field of ultrafast spectrum measurement. In the system, a laser generation device generates first laser and second laser, and the first laser is converted into left-handed circularly polarized light or right-handed circularly polarized light through a pump light polarization device to serve as pump light for exciting a sample to be detected; the first Glan prism converts the second laser into detection light which is linearly polarized in a specified direction so as to detect the sample to be detected; the first lambda / 4 wave plate is used for converting the detection light after detecting the to-be-detected sample into linearly polarized light with mutually vertical polarization; the Wollaston prism enables the linearly polarized light with mutually vertical polarization to be respectively transmitted to the measuring device along different directions; the measuring device calculates the transient absorption spectrum of the left-hand circularly polarized probe light and the transient absorption spectrum of the right-hand circularly polarized probe light. The system can simultaneously measure the transient absorption spectrums of the left-hand circularly polarized light and the right-hand circularly polarized light, so that the measurement error is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrafast spectrum measurement, and in particular to a system, method and device for measuring transient absorption spectrum of polarized light. Background Art

[0002] Transient absorption spectroscopy is a pump-probe technique on an ultrashort time scale that can obtain ultrafast photophysical properties and excited state dynamics of excited samples on a femtosecond time scale. This technique has been widely used in scientific research in many fields such as physics, chemistry, materials, and biology. For example, it can measure and study processes such as photogenerated carrier relaxation and biomolecular reactions in optoelectronic material systems on an ultrafast time scale.

[0003] In recent years, the combination of traditional optoelectronics and spin electronics has led to widespread attention and application of new optoelectronic devices such as spin light-emitting devices and spin Hall devices. For example, due to the breaking of time reversal symmetry, the spin-orbit interaction of two-dimensional transition metal sulfides causes spin splitting of the energy band. The splitting of the K point and the K′ point is opposite. This property is called spin-valley coupling. This inherent property of two-dimensional transition metal sulfides can be used to design spin / valley electronics devices. Among them, the transient absorption spectrum of left-handed and right-handed circularly polarized light is an important means to study the photogenerated carriers and their spin dynamics in the internal energy valley (K point and K′ point) of the material, which facilitates the understanding of the mechanism of spin / valley electronics devices and the design of device structures. In the prior art, the measurement of polarized light transient absorption spectrum is usually carried out by a polarized light transient absorption spectrum measurement system.

[0004] However, a single test process of the transient absorption spectroscopy measurement system in the prior art can only obtain data of one spin direction. If transient absorption spectroscopy measurements of two spins are performed at different times and in different batches, measurement errors will be introduced due to different external conditions. Summary of the invention

[0005] Based on this, it is necessary to provide a system, method and device for measuring the transient absorption spectrum of polarized light in response to the above technical problems. The system can simultaneously measure the transient absorption spectra of left-handed circularly polarized light and right-handed circularly polarized light, thereby reducing the error caused by the secondary measurement.

[0006] The present invention adopts the following technical solutions:

[0007] The present invention provides a transient absorption spectrum measurement system for polarized light, the system comprising: a laser generating device, a pump light polarization device, a detection light polarization device and a measuring device; the detection light polarization device comprises a first Glan prism, a first λ / 4 wave plate and a Wollaston prism;

[0008] A laser generating device, used to generate two lasers, namely a first laser and a second laser;

[0009] A pump light polarization device, used for converting the first laser into left-handed circularly polarized pump light or right-handed circularly polarized pump light; the pump light is used for exciting the sample to be tested;

[0010] A first Glan prism is used to convert the second laser into a detection light with linear polarization in a specified direction; the detection light is used to detect the sample to be tested;

[0011] The first λ / 4 wave plate is used to convert the detection light after detecting the sample to be tested into linear polarized light with polarizations perpendicular to each other; the linear polarized light with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively;

[0012] A Wollaston prism is used to make linearly polarized light with polarizations perpendicular to each other propagate in different directions, so that left-handed circularly polarized detection light and right-handed circularly polarized detection light can be received by the measuring device at the same time;

[0013] The measuring device is used to obtain the transient absorption spectrum of the left-handed circularly polarized detection light and the transient absorption spectrum of the right-handed circularly polarized detection light according to the left-handed circularly polarized detection light and the right-handed circularly polarized detection light received simultaneously.

[0014] Preferably, the pump light polarization device comprises a second Glan prism, a λ / 2 wave plate and a second λ / 4 wave plate; one end of the second Glan prism is connected to the laser generating device, and the other end of the second Glan prism is connected to one end of the second λ / 4 wave plate through the λ / 2 wave plate;

[0015] A second Glan prism is used to receive the first laser emitted by the laser generating device and convert the first laser into linearly polarized pump light with adjustable polarization angle together with a λ / 2 wave plate;

[0016] The second λ / 4 wave plate is used to convert the linearly polarized pump light into left-handed circularly polarized light or right-handed circularly polarized light.

[0017] Preferably, the laser generating device comprises a laser amplifier, a beam splitter, a fully automatic optical parametric amplifier, a chopper, a delay line device and a supercontinuum light generating device; the laser amplifier is connected to one end of the beam splitter, the other end of the beam splitter is respectively connected to one end of the fully automatic optical parametric amplifier and the supercontinuum light generating device, the other end of the fully automatic optical parametric amplifier is connected to one end of the chopper, the other end of the chopper is connected to one end of the delay line device, the other end of the delay line device is connected to the pump light polarization device, and the other end of the supercontinuum light generating device is connected to one end of the first Glan prism;

[0018] A beam splitter is used to receive the laser emitted by the laser amplifier, and generate reflected light and transmitted light after reflecting and transmitting the laser, and output the reflected light as a first laser with a preset wavelength and pulse width through a fully automatic optical parametric amplifier, and generate supercontinuum white light with a preset spectral range through a supercontinuum light generating device and output the transmitted light as a second laser;

[0019] A chopper, used for adjusting the repetition rate of the first laser from 500 Hz to 250 Hz;

[0020] The delay line device is used to adjust the optical path of the first laser so as to adjust the time when the first laser reaches the sample to be measured compared with the time when the second laser reaches the sample to be measured.

[0021] Preferably, the system further comprises a sample loading device; focusing lenses are respectively arranged between the sample loading device and the pump light polarization device and the supercontinuum light generating device; the sample loading device is a vacuum device for placing the sample to be tested, the sample loading device is a vacuum device with a transparent glass window, and the sample loading device comprises a three-dimensional movable sample holder, the sample to be tested, a liquid helium circulation cooling device and a vacuum gauge; the pump light output by the pump light polarization device and the detection light output by the supercontinuum light generating device are respectively focused on the sample to be tested through the corresponding focusing lenses and the vacuum glass window;

[0022] Three-dimensional movable sample rack for placing samples to be tested;

[0023] A liquid helium circulation cooling device is used to adjust the temperature in the sample loading device to adjust the temperature of the sample to be tested;

[0024] Vacuum gauge, used to detect the vacuum level in the sample loading device.

[0025] Preferably, the measuring device comprises a first spectrometer, a second spectrometer and a computer control unit;

[0026] a first spectrometer for receiving the left-handed circularly polarized detection light emitted by the Wollaston prism and sending spectrum information of the left-handed circularly polarized detection light to a computer control unit;

[0027] a second spectrometer for receiving the right-handed circularly polarized probe light represented by the Wollaston prism emission and sending spectrum information of the right-handed circularly polarized probe light to the computer control unit;

[0028] The computer control unit is used to obtain the transient absorption spectrum of the left-handed circularly polarized detection light and the transient absorption spectrum of the right-handed circularly polarized detection light according to the spectral information of the received left-handed circularly polarized detection light and the right-handed circularly polarized detection light.

[0029] Preferably, the laser amplifier, the fully automatic optical parametric amplifier, the chopper, the delay line device, the first spectrometer and the second spectrometer are all electrically connected to the computer control unit so that the computer control unit controls the coordinated operation of the components.

[0030] The present invention provides a method for measuring transient absorption spectrum of polarized light, which is applied to the above-mentioned transient absorption spectrum measurement system of polarized light. The method comprises:

[0031] Controlling the laser generating device to generate the first laser and the second laser, and adjusting the optical path of the first laser to ensure that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser;

[0032] The first laser is converted into left-handed circularly polarized or right-handed circularly polarized pump light by a pump light polarization device, and the left-handed circularly polarized or right-handed circularly polarized pump light is emitted onto the sample to be tested to excite the sample to be tested;

[0033] The second laser is converted into detection light by a Glan prism in a detection light polarization device, and the sample to be tested is detected by the detection light, and the detection light passing through the sample to be tested passes through a first λ / 4 wave plate and a Wollaston prism in the detection light polarization device to convert the detection light into linear polarized light with polarizations perpendicular to each other; the detection light passing through the Glan prism in the detection light polarization device is a synthesis of left-handed circularly polarized detection light and right-handed circularly polarized detection light; the linear polarized lights with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively;

[0034] The detection light representing left-handed circular polarization and the detection light representing right-handed circular polarization are respectively received by the measuring device, and the transient absorption spectrum of the left-handed circular polarization detection light and the transient absorption spectrum of the right-handed circular polarization detection light are obtained based on the received left-handed circular polarization detection light and the received right-handed circular polarization detection light.

[0035] Preferably, the process of acquiring the transient absorption spectrum of the left-handed circularly polarized detection light includes:

[0036] Obtaining the change in transmittance of the received left-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time according to the change in transmittance of the left-handed circularly polarized detection light in the presence or absence of pump light; or,

[0037] The change in reflectivity of the received left-handed circularly polarized detection light in the presence or absence of pump light is obtained, and based on the change in reflectivity of the left-handed circularly polarized detection light in the presence or absence of pump light, the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time is calculated.

[0038] Preferably, the process of acquiring the transient absorption spectrum of the right-handed circularly polarized detection light includes:

[0039] Obtaining the change in transmittance of the received right-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the right-handed polarized light of the sample to be tested at the corresponding test delay time according to the change in transmittance of the right-handed circularly polarized detection light in the presence or absence of pump light; or,

[0040] The change in reflectivity of the received right-handed circularly polarized detection light in the presence or absence of pump light is obtained, and based on the change in reflectivity of the right-handed circularly polarized detection light in the presence or absence of pump light, the transient absorption spectrum of the right-handed polarized light of the sample to be tested at the corresponding test delay time is calculated.

[0041] The present invention provides a device for measuring transient absorption spectra of polarized light, comprising:

[0042] The laser generating module is used to control the laser generating device to generate the first laser and the second laser, and adjust the optical path of the first laser to ensure that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser;

[0043] An excitation module, used for converting the first laser into left-handed circularly polarized or right-handed circularly polarized pump light through a pump light polarization device, and emitting the left-handed circularly polarized or right-handed circularly polarized pump light onto a sample to be tested, so as to excite the sample to be tested;

[0044] A detection module is used to convert the second laser into detection light through a Glan prism in a detection light polarization device, detect the sample to be tested through the detection light, and convert the detection light through the sample to be tested into linear polarized light with polarizations perpendicular to each other through a first λ / 4 wave plate and a Wollaston prism in the detection light polarization device; the detection light passing through the Glan prism in the detection light polarization device is a synthesis of left-handed circularly polarized detection light and right-handed circularly polarized detection light; the linear polarized lights with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively;

[0045] The measuring module is used to respectively receive the detection light representing left-handed circular polarization and the detection light representing right-handed circular polarization through a measuring device, and obtain the transient absorption spectrum of the left-handed circular polarization detection light and the transient absorption spectrum of the right-handed circular polarization detection light according to the received left-handed circular polarization detection light and the received right-handed circular polarization detection light.

[0046] The present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the method for measuring transient absorption spectra of polarized light is implemented.

[0047] The present invention provides a computer device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for measuring transient absorption spectra of polarized light when executing the program.

[0048] At least one of the above technical solutions adopted by the present invention can achieve the following beneficial effects:

[0049] In the transient absorption spectrum measurement system of polarized light provided by the present invention, a first laser and a second laser are generated by a laser generating device, a pump light polarization system converts the first laser into left-handed circularly polarized light or right-handed circularly polarized light to excite a sample, and a first Glan prism converts the second laser into a detection light which can be regarded as a synthesis of left-handed and right-handed circularly polarized light with equal amplitudes to detect the sample. After the detection of the detection light is completed, the left-handed and right-handed circularly polarized detection lights are converted into linearly polarized lights with polarizations perpendicular to each other by a first λ / 4 wave plate, and then a Wollaston prism is used to allow the linearly polarized lights with polarizations perpendicular to each other to propagate separately in different directions. In this way, the left-handed and right-handed circularly polarized lights can be observed simultaneously, that is, the distribution of carriers on the K and K' energy valleys can be obtained simultaneously, and the transient absorption spectrum of the left-handed circularly polarized light and the transient absorption spectrum of the right-handed circularly polarized light can be measured simultaneously, thereby reducing the measurement error. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0051] Figure 1 A schematic structural diagram of a polarized light transient absorption spectrum measurement system provided by the present invention;

[0052] Figure 2 A schematic diagram of the structure of another polarized light transient absorption spectrum measurement system provided by the present invention;

[0053] Figure 3 A schematic diagram of the structure of another polarized light transient absorption spectrum measurement system provided by the present invention;

[0054] Figure 4 A schematic diagram of the structure of another polarized light transient absorption spectrum measurement system provided by the present invention;

[0055] Figure 5 A schematic diagram of the structure of another polarized light transient absorption spectrum measurement system provided by the present invention;

[0056] Figure 6 A schematic diagram of the structure of another polarized light transient absorption spectrum measurement system provided by the present invention;

[0057] Figure 7 A schematic flow chart of a method for measuring transient absorption spectra of polarized light provided by the present invention;

[0058] Figure 8 A schematic flow chart of another method for measuring transient absorption spectra of polarized light provided by the present invention;

[0059] Fig. 9 A schematic diagram of a device for measuring transient absorption spectra of polarized light provided by the present invention;

[0060] Fig.10 A schematic diagram of a computer device for realizing a method for measuring transient absorption spectra of polarized light provided by the present invention.

[0061] Description of reference numerals:

[0062] 100. system; 101. laser generating device; 102. pump light polarization device; 103. probe light polarization device; 104. measuring device; 105. first Glan prism; 106. first λ / 4 wave plate; 107. Wollaston prism; 108. sample to be measured; 109. sample loading device;

[0063] 201, second Glan prism; 202, λ / 2 wave plate; 203, second λ / 4 wave plate;

[0064] 301. Laser amplifier; 302. Beam splitter; 303. Fully automatic optical parametric amplifier; 304. Chopper; 305. Delay line device; 306. Supercontinuum light generating device;

[0065] 401, focusing lens;

[0066] 501, a first spectrometer; 502, a second spectrometer; 503, a computer control unit. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0069] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0070] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0071] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "connected" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0072] The present invention provides a system for measuring transient absorption spectra of polarized light, such as Figure 1 As shown, the system 100 includes: a laser generating device 101 , a pump light polarization device 102 , a detection light polarization device 103 and a measuring device 104 ; the detection light polarization device 103 includes a first Glan prism 105 , a first λ / 4 wave plate 106 and a Wollaston prism 107 .

[0073] The laser generating device 101 is used to generate two lasers, namely a first laser and a second laser.

[0074] The pump light polarization device 102 is used to convert the first laser into left-handed circularly polarized pump light or right-handed circularly polarized pump light; the pump light is used to excite the sample to be measured 108.

[0075] The first Glan prism 105 is used to convert the second laser into detection light with linear polarization in a specified direction; the detection light is used to detect the sample 108 to be tested.

[0076] The first λ / 4 wave plate 106 is used to convert the detection light after detecting the sample to be tested into linear polarized light with polarizations perpendicular to each other; the linear polarized light with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively.

[0077] The Wollaston prism 107 is used to make linearly polarized lights with polarizations perpendicular to each other propagate in different directions, so that left-handed circularly polarized detection light and right-handed circularly polarized detection light can be received by the measuring device 104 at the same time.

[0078] The measuring device 104 is used to obtain a transient absorption spectrum of the left-handed circularly polarized detection light and a transient absorption spectrum of the right-handed circularly polarized detection light according to the simultaneously received left-handed circularly polarized detection light and the right-handed circularly polarized detection light.

[0079] It should be noted that the system 100 further includes a sample loading device 109 , and the sample loading device 109 is used to load the sample 108 to be tested.

[0080] Among them, the output end of the laser generating device 101 is respectively connected to the first Glan prism 105 of the detection light polarization device 103 and one end of the pump light polarization device 102, the other ends of the first Glan prism 105 of the detection light polarization device 103 and the pump light polarization device 102 are both connected to one end of the sample loading device 109, the other end of the sample loading device 109 is connected to one end of the first λ / 4 wave plate 106 in the detection light polarization device 103, the other end of the first λ / 4 wave plate 106 is connected to one end of the Wollaston prism 107, and the other end of the Wollaston prism 107 is respectively connected to the measuring device 104.

[0081] The first Glan prism (Glan) 105 can filter out linear polarized light in other directions to obtain linearly polarized detection light in a single direction, wherein the linearly polarized detection light can be regarded as a synthesis of two left-handed circularly polarized lights and right-handed circularly polarized lights with equal amplitudes; the first λ / 4 wave plate 106 can convert the circularly polarized signal light in the detection light into linearly polarized signal light, that is, the first λ / 4 wave plate 106 can convert the left-handed circularly polarized light and the right-handed circularly polarized light into linearly polarized lights with mutually perpendicular polarizations; the Wollaston prism (Wollaston) 107 can decompose the linearly polarized detection light into left-handed and right-handed circularly polarized detection lights, and allow them to propagate separately in different directions at a certain angle.

[0082] In an exemplary embodiment, Figure 2As shown, the pump light polarization device 102 includes a second Glan prism 201, a λ / 2 wave plate 202 and a second λ / 4 wave plate 203; one end of the second Glan prism 201 is connected to the laser generating device 101, and the other end of the second Glan prism 201 is connected to one end of the second λ / 4 wave plate 203 through the λ / 2 wave plate 202.

[0083] The second Glan prism 201 is used to receive the first laser emitted by the laser generating device 101, and convert the first laser into linearly polarized pump light with adjustable polarization angle together with the λ / 2 wave plate 202; the second λ / 4 wave plate 203 is used to convert the linearly polarized pump light into left-handed circularly polarized light or right-handed circularly polarized light.

[0084] Among them, the first laser emitted by the laser generating device 101 first enters the second Glan prism 201. The second Glan prism 201 and the λ / 2 wave plate 202 convert the linearly polarized first laser output by the laser generating device 101 into a linearly polarized pump light with an adjustable polarization angle. The polarization direction forms an angle of 45 degrees clockwise or 45 degrees counterclockwise with the fast axis of the second λ / 4 wave plate 203, which can form left-handed circularly polarized light or right-handed circularly polarized light, respectively, and finally serve as the pump light for exciting the sample.

[0085] In an exemplary embodiment, Figure 3 As shown, the laser generating device 101 includes a laser amplifier 301, a beam splitter 302, a fully automatic optical parametric amplifier 303, a chopper 304, a delay line device 305 and a supercontinuum light generating device 306; the laser amplifier 301 is connected to one end of the beam splitter 302, the other end of the beam splitter 302 is respectively connected to one end of the fully automatic optical parametric amplifier 303 and the supercontinuum light generating device 306, the other end of the fully automatic optical parametric amplifier 303 is connected to one end of the chopper 304, the other end of the chopper 304 is connected to one end of the delay line device 305, the other end of the delay line device 305 is connected to the pump light polarization device 102, and the other end of the supercontinuum light generating device 306 is connected to one end of the first Glan prism 105.

[0086] The beam splitter 302 is used to receive the laser emitted by the laser amplifier 301, and generate reflected light and transmitted light after reflection and transmission of the laser, and the reflected light is output as a first laser with a preset wavelength and pulse width through the fully automatic optical parametric amplifier 303, and the transmitted light is generated as a supercontinuum white light with a preset spectral range through the supercontinuum light generating device 306 and output as a second laser; the chopper 304 is used to adjust the repetition rate of the first laser from 500 Hz to 250 Hz; the delay line device 305 is used to adjust the optical path of the first laser to adjust the time it takes for the pump light to reach the sample to be tested 108 compared to the detection light.

[0087] The other end of the delay line device 305 is connected to the pump light polarization device 102 , and is substantially connected to the second Glan prism 201 in the pump light polarization device 102 .

[0088] The laser amplifier 301 can be a femtosecond laser amplifier, which can generate ultrafast lasers and be divided into a beam of light with higher power and a beam of light with lower power after passing through the beam splitter 302; for example, the femtosecond laser amplifier outputs a laser with a pulse width of 35fs, a repetition rate of 500Hz, and a central wavelength of 800nm. The femtosecond laser is divided into two beams of light (transmitted light and reflected light) after passing through the transmission and reflection (2:8) beam splitter 302.

[0089] The reflected light has a relatively strong energy, and the pump light of the required wavelength and pulse width is outputted through the fully automatic optical parametric amplifier 303, and then the repetition rate of the pump light can be changed from 500 Hz to 250 Hz through the chopper 304; the pump light reaches the delay line device 305 after passing through the chopper 304, and the position of the delay line is controlled by the measuring device 104, so as to adjust the test delay time of the first laser, so as to adjust the time when the pump light reaches the sample to be tested 108 compared with the detection light. Then, the first laser reaches the second Glan prism 201 of the pump light polarization system through the delay line device 305.

[0090] The energy of the transmitted light part is relatively weak, and it passes through the supercontinuum light generating device 306, for example, and is focused by a lens onto a 5 mm thick sapphire crystal (or calcium fluoride crystal, or a cuvette filled with heavy water), to generate supercontinuum white light with a spectral range of 400-800 nm as the second laser (detection light).

[0091] Among them, the femtosecond laser amplifier mainly includes diode pumping, neodymium-doped yttrium vanadate continuous laser, titanium sapphire-doped mode-locked seed laser, neodymium-doped lithium yttrium fluoride laser and titanium sapphire-doped regenerative amplifier, which generates femtosecond pulse laser with a repetition rate of 500Hz and a central wavelength of 800nm.

[0092] The delay line device 305 includes a collimation system and an electric precision mechanical translation stage. By adjusting the position of the electric precision mechanical translation stage (ie, the optical path of the pump light), the time it takes for the pump light to reach the sample 109 compared to the detection light is controlled.

[0093] The supercontinuum light generating device 306 includes a focusing-collimation system and a supercontinuum light generating medium. The supercontinuum light generating medium is a nonlinear optical medium, such as heavy water, sapphire or calcium fluoride. A suitable medium can be selected according to experimental requirements.

[0094] In one embodiment, Figure 4As shown, focusing lenses 401 are respectively arranged between the sample loading device 109 and the pump light polarization device 102 and the supercontinuum light generating device 306; the sample loading device 109 is a vacuum device with a transparent glass window, and the sample loading device 109 includes a three-dimensional movable sample holder, a sample to be tested 108, a liquid helium circulation cooling device and a vacuum gauge; the pump light output by the pump light polarization device 102 and the detection light output by the supercontinuum light generating device 306 are respectively focused onto the sample to be tested 108 via the corresponding focusing lenses 401 through the vacuum glass window.

[0095] A three-dimensional movable sample holder is used to place the sample 108 to be tested; a liquid helium circulation cooling device is used to adjust the temperature in the sample loading device 109 to adjust the temperature of the sample 108 to be tested; and a vacuum gauge is used to detect the vacuum degree in the sample loading device 109 .

[0096] The liquid helium circulation cooling device can provide an extreme environment of precise temperature control in the entire temperature range of 5K to 300K for the sample 108 to be tested; the vacuum degree in the sample loading device 109 can reach 10-7mbar.

[0097] The detection light and the pump light are converged onto the sample 108 to be tested through the vacuum glass window of the sample loading device, and the detection light then passes through the vacuum glass window into the first λ / 4 wave plate 106 of the detection light polarization system.

[0098] According to theoretical calculations, the measurement of the transient absorption spectrum of polarized light of optoelectronic materials needs to be carried out in a low-temperature environment. Therefore, in this embodiment, a liquid helium circulating cooling device is provided to control the temperature of the sample 108 to be tested in the sample loading device 109 to be in the required low-temperature environment during the measurement process, so that the measurement system can control the ambient temperature of the sample 108 to be tested and measure the transient absorption spectra of two spin directions at one time, thereby reducing measurement errors and shortening test time.

[0099] It should be noted that in Figure 4 In the present application, not only a focusing lens 401 is respectively arranged between the sample loading device 109 and the pump light polarization device 102 and the supercontinuum light generating device 306, but also a focusing lens 401 is arranged between the sample loading device and the first λ / 4 wave plate 106, and two focusing lenses 401 are respectively arranged between the Wollaston prism 107 and the measuring device 104.

[0100] The system 100 also includes five focusing lenses 401, see Figure 4A focusing lens 401 is arranged between the first Glan prism 105 and the sample loading device 109 to focus the detection light emitted by the first Glan prism 105 onto the sample 108 to be measured in the sample loading device 109; a focusing lens 401 is arranged between the pump light polarization device 102 and the sample loading device 109 to focus the pump light emitted by the pump light polarization device 102 onto the sample 108 to be measured in the sample loading device 109; a focusing lens 401 is arranged between the sample loading device 109 and the first λ / 4 wave plate 106, and two focusing lenses 401 are arranged between the Wollaston prism 107 and the measuring device 104 to respectively focus the left-handed circularly polarized detection light and the right-handed circularly polarized detection light emitted by the Wollaston prism 107 onto the measuring device 104 through two optical paths.

[0101] In an exemplary embodiment, Figure 5 As shown, the measuring device 104 includes a first spectrometer 501, a second spectrometer 502 and a computer control unit 503; one end of the first spectrometer 501 and the second spectrometer 502 are respectively connected to the Wollaston prism 107 through a focusing lens 401, and the other ends of the first spectrometer 501 and the second spectrometer 502 are respectively connected to the computer control unit 503.

[0102] The first spectrometer 501 is used to receive the detection light representing left-handed circular polarization emitted by the Wollaston prism 107, and send the spectral information of the left-handed circular polarization detection light to the computer control unit 503; the second spectrometer 502 is used to receive the detection light representing right-handed circular polarization emitted by the Wollaston prism 107, and send the spectral information of the right-handed circular polarization detection light to the computer control unit 503; the computer control unit 503 is used to obtain the transient absorption spectrum of the left-handed circular polarization detection light and the transient absorption spectrum of the right-handed circular polarization detection light according to the spectral information of the received left-handed circular polarization detection light and the right-handed circular polarization detection light.

[0103] The Wollaston prism 107 emits the decomposed left-handed and right-handed circularly polarized detection light in different directions, and then is received by the first spectrometer 501 and the second spectrometer 502 respectively; that is, the first spectrometer 501 receives the detection light representing left-handed circular polarization emitted by the Wollaston prism 107, and analyzes the spectrum information of the left-handed circularly polarized detection light according to the received left-handed circularly polarized detection light, and then sends the spectrum information of the left-handed circularly polarized detection light to the computer control unit 503; the second spectrometer 502 receives the detection light representing right-handed circular polarization emitted by the Wollaston prism 107, and analyzes the spectrum information of the right-handed circularly polarized detection light according to the received right-handed circularly polarized detection light, and then sends the spectrum information of the right-handed circularly polarized detection light to the computer control unit 503. The spectrum information may include transmittance, reflectivity, absorptivity, etc.

[0104] In an exemplary embodiment, Figure 6 As shown, the laser amplifier 301, the fully automatic optical parametric amplifier 303, the chopper 304, the delay line device 305, the first spectrometer 501 and the second spectrometer 502 are all electrically connected to the computer control unit 503 so that the computer control unit 503 controls the coordinated operation of each component.

[0105] The computer control unit 503 can control the output power of the laser amplifier 301, the gain of the fully automatic optical parametric amplifier 303, the switch state of the chopper 304, the position of the delay line in the delay line device 305, and the working state of the first spectrometer 501 and the second spectrometer 502, etc. For example, the computer control unit 503 can adjust the position of the delay line according to the preset interval control instruction, so that the detection light has a delay time relative to the pump light reaching the sample to be tested 108, and then read and process the spectral shape and intensity of the detection light before and after the pump light excites the sample to be tested 108, and finally calculate the transient absorption spectrum of the left-handed and right-handed circularly polarized light of the sample to be tested 108 at the corresponding delay time according to the spectral data.

[0106] Based on the above system, the present invention also provides a method for testing transient absorption spectrum of polarized light, which is applied to the transient absorption spectrum measurement system of polarized light in any of the above embodiments. Figure 7 As shown, the specific steps include:

[0107] S701, controlling a laser generating device to generate a first laser and a second laser, and adjusting the optical path of the first laser to ensure that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser.

[0108] It should be noted that ensuring that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser is essentially ensuring that there is a test delay time for the detection light to reach the sample to be tested relative to the pump light.

[0109] When measuring the transient absorption spectrum of polarized light, first, turn on the laser generating device to generate pump light and probe light, and adjust the optical path of the pump light so that there is a delay when the probe light and the pump light reach the sample to be measured. In this way, the spectral information of the probe light before and after the pump light excites the sample to be measured can be collected.

[0110] S702, converting the first laser into left-handed circularly polarized or right-handed circularly polarized pump light through a pump light polarization device, and emitting the left-handed circularly polarized or right-handed circularly polarized pump light onto the sample to be tested to excite the sample to be tested.

[0111] It should be noted that when left-handed circularly polarized pump light or right-handed circularly polarized pump light is used as a condition for exciting the sample to be tested, the pump light polarization system can be set to convert the pump light into left-handed circularly polarized pump light or right-handed circularly polarized pump light according to the experimental requirements, so as to measure the material properties under different excitation conditions, that is, the transient absorption spectrum of left-handed circularly polarized light and the transient absorption spectrum of right-handed circularly polarized light under different polarized light excitation.

[0112] S703, converting the second laser into detection light through the Glan prism in the detection light polarization device, and detecting the sample to be tested through the detection light, and passing the detection light that has passed through the sample to be tested through the first λ / 4 wave plate and the Wollaston prism in the detection light polarization device to convert the detection light into linear polarized light with polarizations perpendicular to each other; the detection light that passes through the Glan prism in the detection light polarization device is a synthesis of left-handed circularly polarized detection light and right-handed circularly polarized detection light; the linear polarized lights with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light, respectively.

[0113] S704, respectively receiving the detection light representing left-handed circular polarization and the detection light representing right-handed circular polarization through a measuring device, and obtaining a transient absorption spectrum of the left-handed circular polarization detection light and a transient absorption spectrum of the right-handed circular polarization detection light based on the received left-handed circular polarization detection light and the received right-handed circular polarization detection light.

[0114] The specific definition of the method for measuring the transient absorption spectrum of polarized light in this embodiment can be found in the above definition of the system for measuring the transient absorption spectrum of polarized light, which will not be described in detail here.

[0115] In an exemplary embodiment, the optical path of the pump light can be adjusted by moving the position of the optical element on the delay line device based on the step file, so that the pump light increases the test delay time based on the reference position; the reference position is the position of the delay line when the pump light and the detection light reach the sample to be tested at the same time.

[0116] Among them, the step length file can be a data file used to define the change of step length parameters during the test process. The step length file can include the optical path adjusted each time; it can be based on the reference position, gradually increase the optical path according to the preset step length, thereby increasing the test delay time.

[0117] Among them, since the delay line device changes the test delay time, the time when the detection light and the pump light reach the sample to be tested is inconsistent. In addition, due to the chopper, when the detection light detects the sample to be tested, the sample to be tested exists in two states: excited and unexcited. Therefore, the detection light received by the spectrometer also exists in two states: excited by pump light and not excited by pump light. The transient absorption spectrum of polarized light of the sample to be tested at the corresponding test delay time can be determined based on the spectral information of the detection light with or without pump light.

[0118] Among them, taking the spectral information of transmittance and reflectance as an example for explanation, the process of acquiring the transient absorption spectrum of left-handed circularly polarized detection light includes: acquiring the change of transmittance of the received left-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time according to the change of transmittance of the left-handed circularly polarized detection light in the presence or absence of pump light; or, acquiring the change of reflectance of the received left-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time according to the change of reflectance of the left-handed circularly polarized detection light in the presence or absence of pump light.

[0119] The first spectrometer analyzes the left-handed circularly polarized detection light received in the presence of pump light to determine the transmittance or reflectance of the left-handed circularly polarized detection light in the presence of pump light, and the first spectrometer analyzes the left-handed circularly polarized detection light received in the absence of pump light to determine the transmittance or reflectance of the left-handed circularly polarized detection light in the absence of pump light.

[0120] According to the transmittance of the left-handed circularly polarized detection light in the presence of pump light and the transmittance of the left-handed circularly polarized detection light in the absence of pump light, the change of the transmittance of the left-handed circularly polarized detection light in the presence of pump light and the absence of pump light is calculated, as shown in formula (1).

[0121]

[0122] Among them, T pump+probe is the transmittance in the presence of pump light, T probe is the transmittance without pump light, is the change of transmittance.

[0123] According to the change of the transmittance of the left-handed circularly polarized detection light in the presence or absence of pump light, the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time is calculated, as shown in formula (2).

[0124]

[0125] Wherein, ΔOD is the transient absorption spectrum of left-handed polarized light of the sample to be tested at the corresponding test delay time.

[0126] According to the reflectivity of the left-handed circularly polarized detection light in the presence of pump light and the reflectivity of the left-handed circularly polarized detection light in the absence of pump light, the change of the reflectivity of the left-handed circularly polarized detection light in the presence or absence of pump light is calculated, as shown in formula (3).

[0127]

[0128] Among them, R pump+probe is the reflectivity in the presence of pump light, R probe is the reflectivity without pump light, is the change of reflectivity.

[0129] According to the change of reflectivity of left-handed circularly polarized detection light in the presence or absence of pump light, the transient absorption spectrum of left-handed polarized light of the sample to be tested at the corresponding test delay time is calculated, as shown in formula (4).

[0130]

[0131] In an exemplary embodiment, the process of acquiring the transient absorption spectrum of right-handed circularly polarized detection light includes: acquiring the change in transmittance of the received right-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the right-handed polarized light of the sample to be tested at the corresponding test delay time based on the change in transmittance of the right-handed circularly polarized detection light in the presence or absence of pump light; or, acquiring the change in reflectivity of the received right-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the right-handed polarized light of the sample to be tested at the corresponding test delay time based on the change in reflectivity of the right-handed circularly polarized detection light in the presence or absence of pump light.

[0132] The specific principle of calculating the transient absorption spectrum of right-handed polarized light in this embodiment is the same as the specific principle of calculating the transient absorption spectrum of left-handed polarized light in the above embodiment, and the embodiments of this application will not be repeated here.

[0133] In an exemplary embodiment, the present application also provides a method for measuring transient absorption spectra of polarized light, wherein the laser generating device includes a femtosecond laser amplifier, a beam splitter, a fully automatic optical parameter device, a delay line device and a supercontinuum light generating device, such as Figure 8 As shown, the method comprises the following steps:

[0134] S801, turn on the femtosecond laser amplifier, and use a beam splitter to split the laser emitted by the femtosecond laser amplifier into two beams: a beam of light with higher energy (reflected light) enters the pump light path, and a beam of light with lower energy (transmitted light) enters the detection light path.

[0135] S802, adjusting the parameters of the fully automatic optical parametric device and the parameters of the chopper, passing the light with stronger energy through the fully automatic optical parametric device and the chopper, and outputting the pump light with the required wavelength, pulse width and repetition rate.

[0136] S803, adjusting the supercontinuum light generating device to output detection light through the supercontinuum light generating device with weaker energy.

[0137] Among them, adjusting the supercontinuum light generating device includes selecting a suitable nonlinear medium (such as heavy water, sapphire or calcium fluoride crystal), and using the supercontinuum light generating device to output supercontinuum white light with suitable intensity and stable spectral shape as detection light.

[0138] S804, adjusting the polarization directions of the pump light and the detection light.

[0139] The polarization direction of the detection light can be adjusted by the first Glan prism in the detection light polarization system; and the polarization direction of the pump light can be adjusted by the second Glan prism, the λ / 2 wave plate and the second λ / 4 wave plate in the pump light polarization system.

[0140] S805, fix the sample to be tested on the sample holder of the sample loading device, evacuate the sample loading device, and set the test temperature.

[0141] Among them, the sample rack is a three-dimensional movable sample rack.

[0142] S806, adjusting the delay line so that the pump light and the detection light reach the sample at the same time, and increasing the test delay time based on the reference position according to the selected step file.

[0143] Among them, the test delay time is added on the basis of the reference position to ensure that the entire process of sample excitation and carrier relaxation can be detected.

[0144] Before determining the reference position of the delay line, it is necessary to carefully adjust the overlap between the pump light and the probe light, adjust the delay line to find the maximum position of the transient absorption signal, and set the appropriate intensity of the pump light.

[0145] S807, start measuring, and the computer control unit calculates the transient absorption spectra of left-handed and right-handed polarized light of the sample to be tested at the corresponding test delay time.

[0146] Compared with the prior art, the present invention has the following beneficial effects:

[0147] (1) The present invention provides a transient absorption spectrum measurement system for polarized light of spin-valley polarization of transition metal dichalcogenides (TMDs), which can simultaneously detect left-handed and right-handed circularly polarized light in one measurement, that is, simultaneously obtain the distribution of carriers in the K and K' energy valleys, thereby simplifying the experimental process, improving the experimental efficiency, and reducing the measurement error.

[0148] (2) Conventional two-dimensional TMDs materials may exhibit optical properties different from those at room temperature in a low-temperature environment. The present invention provides a test system that combines transient absorption detection technology and a low-temperature control system, bringing a new dimension (temperature) to the study of the properties of two-dimensional TMDs materials.

[0149] (3) The present invention realizes the adjustable polarization angle of the pump light by adding a Glan prism, a λ / 2 wave plate and a λ / 4 wave plate, which can satisfy the excitation of the sample to be tested by pump light with different polarization angles, thereby bringing more comprehensive experimental analysis.

[0150] The above is a method for measuring transient absorption spectrum of polarized light provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding device for measuring transient absorption spectrum of polarized light, such as Fig. 9 shown.

[0151] Fig. 9 A schematic diagram of a polarized light transient absorption spectrum measurement device provided by the present invention, the polarized light transient absorption spectrum measurement device 900 comprises:

[0152] The laser generating module 901 is used to control the laser generating device to generate the first laser and the second laser, and adjust the optical path of the first laser to ensure that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser;

[0153] The excitation module 902 is used to convert the first laser into left-handed circularly polarized or right-handed circularly polarized pump light through a pump light polarization device, and emit the left-handed circularly polarized or right-handed circularly polarized pump light to the sample to be tested to excite the sample to be tested;

[0154] The detection module 903 is used to convert the second laser into detection light through the Glan prism in the detection light polarization device, detect the sample to be tested through the detection light, and convert the detection light through the sample to be tested into linear polarized light with polarizations perpendicular to each other through the first λ / 4 wave plate and the Wollaston prism in the detection light polarization device; the detection light passing through the Glan prism in the detection light polarization device is a synthesis of the left-handed circularly polarized detection light and the right-handed circularly polarized detection light; the linear polarized lights with polarizations perpendicular to each other represent the left-handed circularly polarized detection light and the right-handed circularly polarized detection light respectively;

[0155] The measuring module 904 is used to respectively receive the detection light representing left-handed circular polarization and the detection light representing right-handed circular polarization through a measuring device, and obtain the transient absorption spectrum of the left-handed circular polarization detection light and the transient absorption spectrum of the right-handed circular polarization detection light based on the received left-handed circular polarization detection light and the received right-handed circular polarization detection light.

[0156] The specific definition of the polarized light transient absorption spectrum measurement device can be found in the above definition of the polarized light transient absorption spectrum measurement method, which will not be repeated here. Each module in the above polarized light transient absorption spectrum measurement device can be implemented in whole or in part by software, hardware and a combination thereof. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0157] The present invention also provides a computer-readable storage medium, which stores a computer program, which can be used to execute the above Figure 7 A method for measuring transient absorption spectroscopy of polarized light is provided.

[0158] The present invention also provides Fig.10 The structural diagram of the computer device shown in FIG. Fig.10 As shown in the figure, at the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory, and may also include other hardware required for the business. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to achieve the above Figure 7 A method for measuring transient absorption spectroscopy of polarized light is provided.

[0159] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0160] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A polarized light transient absorption spectrum measurement system, characterized in that: The system comprises: a laser generating device, a pump light polarization device, a detection light polarization device and a measuring device; the detection light polarization device comprises a first Glan prism, a first λ / 4 wave plate and a Wollaston prism; A laser generating device, used to generate two lasers, namely a first laser and a second laser; A pump light polarization device, used for converting the first laser into left-handed circularly polarized pump light or right-handed circularly polarized pump light; the pump light is used for exciting the sample to be tested; A first Glan prism is used to convert the second laser into a detection light with linear polarization in a specified direction; the detection light is used to detect the sample to be tested; The first λ / 4 wave plate is used to convert the detection light after detecting the sample to be tested into linear polarized light with polarizations perpendicular to each other; the linear polarized light with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively; A Wollaston prism is used to make linearly polarized light with polarizations perpendicular to each other propagate in different directions, so that left-handed circularly polarized detection light and right-handed circularly polarized detection light can be received by the measuring device at the same time; The measuring device is used to obtain the transient absorption spectrum of left-handed circularly polarized light and the transient absorption spectrum of right-handed circularly polarized light according to the left-handed circularly polarized detection light and the right-handed circularly polarized detection light received simultaneously.

2. The system according to claim 1, characterized in that The pump light polarization device comprises a second Glan prism, a λ / 2 wave plate and a second λ / 4 wave plate; one end of the second Glan prism is connected to the laser generating device, and the other end of the second Glan prism is connected to one end of the second λ / 4 wave plate through the λ / 2 wave plate; A second Glan prism is used to receive the first laser emitted by the laser generating device and convert the first laser into linearly polarized pump light with adjustable polarization angle together with a λ / 2 wave plate; The second λ / 4 wave plate is used to convert the linearly polarized pump light into left-handed circularly polarized light or right-handed circularly polarized light.

3. The system according to claim 1 or 2, characterized in that: The laser generating device comprises a laser amplifier, a beam splitter, a fully automatic optical parametric amplifier, a chopper, a delay line device and a supercontinuum light generating device; the laser amplifier is connected to one end of the beam splitter, the other end of the beam splitter is respectively connected to one end of the fully automatic optical parametric amplifier and the supercontinuum light generating device, the other end of the fully automatic optical parametric amplifier is connected to one end of the chopper, the other end of the chopper is connected to one end of the delay line device, the other end of the delay line device is connected to the pump light polarization device, and the other end of the supercontinuum light generating device is connected to one end of the first Glan prism; A beam splitter is used to receive the laser emitted by the laser amplifier, and generate reflected light and transmitted light after reflecting and transmitting the laser, and output the reflected light as a first laser with a preset wavelength and pulse width through a fully automatic optical parametric amplifier, and generate supercontinuum white light with a preset spectral range through a supercontinuum light generating device and output the transmitted light as a second laser; A chopper, used for adjusting the repetition rate of the first laser from 500 Hz to 250 Hz; The delay line device is used to adjust the optical path of the first laser so as to adjust the time when the first laser reaches the sample to be measured compared with the time when the second laser reaches the sample to be measured.

4. The system according to claim 3, characterized in that The system also includes a sample loading device; focusing lenses are respectively arranged between the sample loading device and the pump light polarization device and the supercontinuum light generating device; the sample loading device is a vacuum device with a transparent glass window, and the sample loading device includes a three-dimensional movable sample holder, a sample to be tested, a liquid helium circulation cooling device and a vacuum gauge; the pump light output by the pump light polarization device and the detection light output by the supercontinuum light generating device are respectively focused on the sample to be tested through the vacuum glass window via corresponding focusing lenses; Three-dimensional movable sample rack for placing samples to be tested; A liquid helium circulation cooling device is used to adjust the temperature in the sample loading device to adjust the temperature of the sample to be tested; Vacuum gauge, used to detect the vacuum level in the sample loading device.

5. The system according to claim 3, characterized in that The measuring device comprises a first spectrometer, a second spectrometer and a computer control unit; a first spectrometer for receiving the left-handed circularly polarized detection light emitted by the Wollaston prism and sending spectrum information of the left-handed circularly polarized detection light to a computer control unit; a second spectrometer for receiving the right-handed circularly polarized probe light emitted by the Wollaston prism and sending spectrum information of the right-handed circularly polarized probe light to the computer control unit; The computer control unit is used to obtain the transient absorption spectrum of the left-handed circularly polarized detection light and the transient absorption spectrum of the right-handed circularly polarized detection light according to the spectral information of the received left-handed circularly polarized detection light and the right-handed circularly polarized detection light.

6. The system according to claim 5, characterized in that The laser amplifier, the fully automatic optical parametric amplifier, the chopper, the delay line device, the first spectrometer and the second spectrometer are all electrically connected to the computer control unit so that the computer control unit controls the coordinated operation of the components.

7. A method for measuring transient absorption spectra of polarized light, characterized in that: The method is applied to the system according to any one of claims 1 to 6, and the method comprises: Controlling the laser generating device to generate the first laser and the second laser, and adjusting the optical path of the first laser to ensure that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser; The first laser is converted into left-handed circularly polarized or right-handed circularly polarized pump light by a pump light polarization device, and the left-handed circularly polarized or right-handed circularly polarized pump light is emitted onto the sample to be tested to excite the sample to be tested; The second laser is converted into detection light by a Glan prism in a detection light polarization device, and the sample to be tested is detected by the detection light, and the detection light passing through the sample to be tested passes through a first λ / 4 wave plate and a Wollaston prism in the detection light polarization device to convert the detection light into linear polarized light with polarizations perpendicular to each other; the detection light passing through the Glan prism in the detection light polarization device is a synthesis of left-handed circularly polarized detection light and right-handed circularly polarized detection light; the linear polarized lights with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively; The detection light representing left-handed circular polarization and the detection light representing right-handed circular polarization are respectively received by the measuring device, and the transient absorption spectrum of the left-handed circular polarization detection light and the transient absorption spectrum of the right-handed circular polarization detection light are obtained based on the received left-handed circular polarization detection light and the received right-handed circular polarization detection light.

8. The method according to claim 7, characterized in that The process of acquiring the transient absorption spectrum of the left-handed circularly polarized detection light comprises: Obtaining the change in transmittance of the received left-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time according to the change in transmittance of the left-handed circularly polarized detection light in the presence or absence of pump light; or, The change in reflectivity of the received left-handed circularly polarized detection light in the presence or absence of pump light is obtained, and based on the change in reflectivity of the left-handed circularly polarized detection light in the presence or absence of pump light, the transient absorption spectrum of the left-handed polarized light of the sample to be tested at the corresponding test delay time is calculated.

9. The method according to claim 7, characterized in that: The process of acquiring the transient absorption spectrum of the right-handed circularly polarized detection light comprises: Obtaining the change in transmittance of the received right-handed circularly polarized detection light in the presence or absence of pump light, and calculating the transient absorption spectrum of the right-handed polarized light of the sample to be tested at the corresponding test delay time according to the change in transmittance of the right-handed circularly polarized detection light in the presence or absence of pump light; or, The change in reflectivity of the received right-handed circularly polarized detection light in the presence or absence of pump light is obtained, and based on the change in reflectivity of the right-handed circularly polarized detection light in the presence or absence of pump light, the transient absorption spectrum of the right-handed polarized light of the sample to be tested at the corresponding test delay time is calculated.

10. A polarized light transient absorption spectrum measuring device, characterized in that: The device is applied to the system according to any one of claims 1 to 6, and the device comprises: The laser generating module is used to control the laser generating device to generate the first laser and the second laser, and adjust the optical path of the first laser to ensure that there is a test delay time for the second laser to reach the sample to be tested relative to the first laser; An excitation module, used for converting the first laser into left-handed circularly polarized or right-handed circularly polarized pump light through a pump light polarization device, and emitting the left-handed circularly polarized or right-handed circularly polarized pump light onto a sample to be tested, so as to excite the sample to be tested; A detection module is used to convert the second laser into detection light through a Glan prism in a detection light polarization device, detect the sample to be tested through the detection light, and convert the detection light through the sample to be tested into linear polarized light with polarizations perpendicular to each other through a first λ / 4 wave plate and a Wollaston prism in the detection light polarization device; the detection light passing through the Glan prism in the detection light polarization device is a synthesis of left-handed circularly polarized detection light and right-handed circularly polarized detection light; the linear polarized lights with polarizations perpendicular to each other represent left-handed circularly polarized detection light and right-handed circularly polarized detection light respectively; The measuring module is used to respectively receive the detection light representing left-handed circular polarization and the detection light representing right-handed circular polarization through a measuring device, and obtain the transient absorption spectrum of the left-handed circular polarization detection light and the transient absorption spectrum of the right-handed circular polarization detection light according to the received left-handed circular polarization detection light and the received right-handed circular polarization detection light.

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