A single-shot polarization-resolved spectroscopy device and method based on vector light field

Abstract

The present invention proposes a single-shot polarization-resolved spectroscopy device and method based on a vector light field, the device comprising a laser, a first half-wave plate, a first polarization beam splitter cube, a first reflector, a second half-wave plate, a second polarization beam splitter cube, a third half-wave plate, a second reflector, a fourth half-wave plate, a third reflector, a fourth reflector, a vortex half-wave plate, a third polarization beam splitter cube, a focusing lens, an atomic molecular vapor absorption chamber and an imaging device. The present invention innovatively designs an optical path structure for single-shot polarization-resolved spectroscopy, so that a pump laser beam and a detection laser beam are generated simultaneously based on the same laser source, and a detection laser beam with multiple polarization states is generated simultaneously based on the same laser source, thereby realizing a single-light source multi-polarization state beam output, which can be applied to nonlinear molecular orientation calibration and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of nonlinear optical applications, and specifically relates to a single-shot polarization-resolved spectroscopy device and a single-shot polarization-resolved spectroscopy method based on a vector light field, and more specifically designs an optical path structure for single-shot polarization resolution based on a vector light field and an optical path adjustment method thereof. Background Art

[0002] Laser plays an increasingly important role in medical diagnosis and treatment due to its high brightness, good directionality, good monochromaticity and good coherence. Since most biological molecules are polar molecules, the arrangement, orientation and structure of the molecules constituting biological tissues will change under the action of polarized lasers, which will affect every process of tissue growth and cell evolution, and accelerate cell regeneration and tissue growth. By changing the polarization state of the incident light and detecting the polarization and intensity of the radiated light (nonlinear optical signal), the orientation of the molecule can be detected. In the prior art, the spectral resolution of the molecular orientation of a nonlinear medium is to allow the detection light of different polarization states to be incident on the nonlinear medium, and to detect the corresponding polarization direction and intensity of the signal light generated based on the four-wave mixing effect to distinguish the nonlinear medium. The spectral resolution of a nonlinear medium needs to be based on the four-wave mixing signals of multiple detection lights of different polarization states at the same time. In the prior art, when performing spectral resolution detection of nonlinear molecular orientation, the acquisition of multiple beams of detection lights of different polarization states is achieved by replacing different detection light sources. The frequent replacement of the detection light source will cause the detection accuracy to be unable to be guaranteed and the operation is very inconvenient. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a single-shot polarization-resolved spectroscopy device and method based on a vector light field in response to the problems of existing multi-light source polarization-resolved nonlinear spectroscopy. By innovatively designing the optical path structure for single-shot polarization-resolved spectroscopy, a pump laser beam and a detection laser beam are simultaneously generated based on the same laser source, and a detection laser beam with multiple polarization states is simultaneously generated based on the same laser source, thereby realizing the output of a single-light source multi-polarization state light beam (single-shot polarization), which can be applied to nonlinear molecular orientation calibration and has broad application prospects.

[0004] To solve the above needs, the technical solution adopted by the present invention is as follows:

[0005] A single-shot polarization-resolved spectroscopy device based on a vector light field comprises: a laser 1, a first half-wave plate 2, a first polarization beam splitter cube 3, a first reflector 4, a second half-wave plate 5, a second polarization beam splitter cube 6, a third half-wave plate 7, a second reflector 8, a fourth half-wave plate 9, a third reflector 10, a fourth reflector 11, a vortex half-wave plate 12, a third polarization beam splitter cube 13, a focusing lens 14, an atomic and molecular vapor absorption chamber 15 and an imaging device 16; wherein the laser 1 and the first half-wave plate 2 form a light source unit for generating a laser beam; the first polarization beam splitter cube 3, the first reflector 4 and the vortex half-wave plate 12 form a detection optical path unit for generating a detection laser beam; the first polarization beam splitter cube 3, the second half-wave plate 5 and the vortex half-wave plate 16 ... The first pump optical path unit is composed of the second polarization splitter cube 6, the third half-wave plate 7, the second reflector 8 and the third polarization splitter cube 13, which is used to generate a first pump laser beam; the second polarization splitter cube 6, the fourth half-wave plate 9, the third reflector 10, the fourth reflector 11 and the third polarization splitter cube 13 form a second pump optical path unit, which is used to generate a second pump laser beam; the focusing lens 14, the atomic and molecular vapor absorption chamber 15 and the imaging device 16 form a four-wave mixing signal generating unit, and the detection laser beam, the first pump laser beam and the second pump laser beam generate a four-wave mixing signal in the four-wave mixing signal generating unit.

[0006] Further, according to the single-shot polarization-resolved spectroscopy device of the present invention, the first pump laser beam and the second pump laser beam incident into the atomic and molecular vapor absorption chamber 15 have a vertical polarization state; the detection laser beam is a radial vector light field including multiple polarization directions, the polarization state of the detection laser beam can be adjusted by a polarizer, and corresponding to different polarization states of the detection laser beam, the atomic and molecular vapor absorption chamber 15 generates a corresponding four-wave mixing signal that can calibrate the orientation of the nonlinear medium molecules inside it.

[0007] Further according to the single-shot polarization-resolved spectroscopy device described in the present invention, the laser 1 in the light source unit is a femtosecond pulse titanium sapphire laser, the output laser beam is a Gaussian laser beam in a linearly polarized state, and the output laser center wavelength is at the absorption wavelength of the atomic and molecular vapor absorption chamber 15.

[0008] Further, according to the single-shot polarization-resolved spectroscopy device described in the present invention, the first polarization beam splitter cube 3, the second polarization beam splitter cube 6 and the third polarization beam splitter cube 13 transmit the laser beam with a horizontal polarization direction and reflect the laser beam with a vertical polarization direction; the first half-wave plate 2, the second half-wave plate 5, the third half-wave plate 7 and the fourth half-wave plate 9 can rotationally adjust the polarization direction of the polarized light; the first half-wave plate 2 and the first polarization beam splitter cube 3 are used to adjust the splitting ratio of the pump laser beam and the detection laser beam, the second half-wave plate 5 and the second polarization beam splitter cube 6 are used to adjust the splitting ratio of the first pump laser beam and the second pump laser beam, the third half-wave plate 7 and the third polarization beam splitter cube 13 are used to adjust the power of the first pump laser beam incident into the atomic and molecular vapor absorption chamber 15, and the fourth half-wave plate 9 and the third polarization beam splitter cube 13 are used to adjust the power of the second pump laser beam incident into the atomic and molecular vapor absorption chamber 15.

[0009] Further, according to the single-shot polarization-resolved spectroscopy device described in the present invention, the laser 1, the first half-wave plate 2, the first polarization beam splitter cube 3, the second half-wave plate 5, the second polarization beam splitter cube 6, the third half-wave plate 7 and the second reflector 8 are sequentially arranged on the same straight optical path, the laser beam generated by the laser 1 passes through the first half-wave plate 2 and is incident on the first polarization beam splitter cube 3, the laser beam transmitted and output by the first polarization beam splitter cube 3 is a pump laser beam with a horizontal polarization state, the laser beam reflected and output by the first polarization beam splitter cube 3 is a detection laser beam with a vertical polarization state, the detection laser beam passes through the vortex half-wave plate 12 to generate a radial vector light field containing multiple polarization directions; the pump laser beam passes through the first polarization beam splitter cube 3, and the pump laser beam passes through the first polarization beam splitter cube 3. The first pump laser beam passes through the third half-wave plate 7 and the second reflector 8 and is incident on the second polarization splitter cube 6. The first pump laser beam passes through the third half-wave plate 7 and the second reflector 8 and is incident on the third polarization splitter cube 13. The second pump laser beam passes through the fourth half-wave plate 9, the third reflector 10 and the fourth reflector 11 and is incident on the third polarization splitter cube 13. The second pump laser beam passes through the third polarization splitter cube 13 and is incident on the third polarization splitter cube 13. The reflected output is the vertical component of the second pump laser beam with a vertical polarization state; the radial vector light field, the vertical component of the first pump laser beam and the vertical component of the second pump laser beam are focused in the atomic and molecular vapor absorption chamber 15 through the focusing lens 14, and the radial vector light field, the vertical component of the first pump laser beam and the vertical component of the second pump laser beam are respectively located at the three vertices of the square on the optical path section before the focusing lens 14.

[0010] Further according to the single-shot polarization-resolved spectroscopy device described in the present invention, in the detection optical path unit, the beam incident end of the first polarization beam splitter cube 3 is arranged opposite to the beam output end of the laser, the beam reflection output end of the first polarization beam splitter cube 3 is arranged opposite to the beam incident end of the first reflector 4, and the beam reflection end of the first reflector 4 is arranged opposite to the vortex half-wave plate 12. The beam transmission process in the detection optical path unit is as follows: the laser beam output by the laser 1 is incident on the first polarization beam splitter cube 3 after the polarization direction is adjusted by the first half-wave plate 2, and the vertical polarization component in the laser beam is reflected by the first polarization beam splitter cube 3 as a detection laser beam and output to the first reflector 4, and is vertically reflected to the vortex half-wave plate 12 by the first reflector 4, and the detection laser beam forms a radial vector light field containing linear polarization states in different directions after passing through the vortex half-wave plate 12.

[0011] Further according to the single-shot polarization-resolved spectroscopy device described in the present invention, the vortex half-wave plate 12 is composed of a plurality of fan-shaped half-wave plates, and the fast axis directions of the respective half-wave plates are evenly arranged according to a rule of deflecting by an angle of 2mπ around a circle. Each half-wave plate causes a corresponding deflection in the polarization direction of the incident laser beam based on its fast axis direction, and the laser beams at different positions passing through the vortex half-wave plate are polarized at different angles, and finally the laser beam emitted through the vortex half-wave plate 12 forms a radial vector light field containing linear polarization states in different directions.

[0012] Further, according to the single-shot polarization-resolved spectroscopy device of the present invention, in the first pump optical path unit, the beam transmission output end of the first polarization beam splitter cube 3 is arranged opposite to the beam incident end of the second polarization beam splitter cube 6, the second half-wave plate 5 is arranged between the first polarization beam splitter cube 3 and the second polarization beam splitter cube 6, the beam transmission output end of the second polarization beam splitter cube 6 is arranged opposite to the beam incident end of the second reflector 8, the third half-wave plate 7 is arranged between the second polarization beam splitter cube 6 and the second reflector 8, and the beam reflection end of the second reflector 8 is arranged opposite to the beam incident end of the third polarization beam splitter cube 13; the beam transmission process of the first pump optical path unit is as follows: the laser beam output by the laser 1 is incident to the first polarization beam splitter cube 3 after the polarization direction is adjusted by the first half-wave plate 2, The horizontal polarization component in the laser beam is transmitted and output by the first polarization splitter cube 3, and is incident on the second half-wave plate 5 as a pump laser beam. After the polarization direction is adjusted by the second half-wave plate 5, it is incident on the second polarization splitter cube 6. The horizontal polarization component in the pump laser beam is transmitted and output by the second polarization splitter cube 6, and is incident on the third half-wave plate 7 as a first pump laser beam. After the polarization direction is adjusted again by the third half-wave plate 7, it is incident on the second reflector 8 and the third polarization splitter cube 13. The vertical polarization component in the first pump laser beam is reflected and output by the third polarization splitter cube 13, and is output to the four-wave mixing signal generating unit as the vertical component of the first pump laser beam.

[0013] Further, according to the single-shot polarization-resolved spectroscopy device described in the present invention, in the second pump optical path unit, the beam reflection output end of the second polarization beam splitter cube 6 is arranged opposite to the beam incident end of the third reflector 10, the fourth half-wave plate 9 is arranged between the second polarization beam splitter cube 6 and the third reflector 10, the beam reflection end of the third reflector 10 is arranged opposite to the beam incident end of the fourth reflector 11, and the beam reflection end of the fourth reflector 11 is arranged opposite to the beam incident end of the third polarization beam splitter cube 13; the beam transmission process of the second pump optical path unit is as follows: the second pump laser beam with a vertical polarization state reflected and output by the second polarization beam splitter cube 6 is incident to the fourth half-wave plate 9, and after the polarization direction is adjusted by the fourth half-wave plate 9, it is incident to the third reflector 10, the fourth reflector 11 and the third polarization beam splitter cube 13, the vertical polarization component in the second pump laser beam is reflected and output by the third polarization beam splitter cube 13, and is output to the four-wave mixing signal generating unit as the second pump laser beam vertical component.

[0014] A single-shot polarization-resolved spectroscopy method based on the single-shot polarization-resolved spectroscopy device of the present invention comprises the following steps:

[0015] Step 1, start the laser, so that the laser beam generated by the laser 1 passes through the first half-wave plate 2 and the first polarization splitter cube 3 in sequence and is divided into a pump laser beam with a horizontal polarization state and a detection laser beam with a vertical polarization state, and the first half-wave plate 2 is rotated to adjust the splitting ratio of the pump laser beam and the detection laser beam to a suitable range;

[0016] Step 2, wherein the detection laser beam reflected and split by the first polarization splitting cube 3 passes through the first reflector 4 and the vortex half-wave plate 12 in sequence to form a radial vector light field with multiple different polarization directions, and is focused by the focusing lens 14 to the atomic and molecular vapor absorption chamber 15;

[0017] Step 3, wherein the pump laser beam transmitted and split by the first polarization splitting cube 3 passes through the second half-wave plate 5 and the second polarization splitting cube 6 in sequence and is split into a first pump laser beam with a horizontal polarization state and a second pump laser beam with a vertical polarization state, and the second half-wave plate 5 is rotated to adjust the splitting ratio of the first pump laser beam and the second pump laser beam to an appropriate range;

[0018] Step 4, wherein the first pump laser beam sequentially passes through the third half-wave plate 7, the second reflector 8, and the third polarization splitter cube 13, and then is focused by the focusing lens 14 on the atomic and molecular vapor absorption chamber 15, and the third half-wave plate is rotated to adjust the power of the first pump laser beam incident on the atomic and molecular vapor absorption chamber to a suitable range; wherein the second pump laser beam sequentially passes through the fourth half-wave plate 9, the third reflector 10, the fourth reflector 11, and the third polarization splitter cube 13, and then is focused by the focusing lens 14 on the atomic and molecular vapor absorption chamber 15, and the fourth half-wave plate is rotated to adjust the power of the second pump laser beam incident on the atomic and molecular vapor absorption chamber to a suitable range;

[0019] Step 5: Continue to adjust the power of the first pump laser beam and the second pump laser beam incident into the atomic molecular vapor absorption chamber and the atomic molecular vapor concentration in the atomic molecular vapor absorption chamber 15 until an obvious four-wave mixing signal light appears on the imaging device 16.

[0020] Step six, then keep the power of the first pump laser beam and the second pump laser beam incident into the atomic and molecular vapor absorption chamber 15 unchanged, dynamically adjust the polarization state of the detection laser beam incident into the atomic and molecular vapor absorption chamber, add a linear polarizer between the vortex half-wave plate and the focusing lens and successively set the linear polarizer at different angles so that the detection laser beam incident into the atomic and molecular vapor absorption chamber has different polarization states, and record the light spot and polarization information of the four-wave mixing signal light obtained under various polarization states through the imaging device 16, so as to obtain the spectral information for distinguishing the nonlinear medium in the atomic and molecular vapor absorption chamber.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1) The present invention innovatively designs an optical path structure for single-shot polarization-resolved spectroscopy, so that a pump laser beam and a detection laser beam are simultaneously generated based on the same laser source, and a detection laser beam with multiple polarization states is simultaneously generated based on the same laser source, thereby realizing the output of a single-light source multi-polarization state beam (single-shot polarization), which can be applied to nonlinear molecular orientation calibration and has broad application prospects.

[0023] 2) The present invention is based on the third-order nonlinear optical effect. The four-wave mixing signal light is obtained by adjusting the pump laser beam and the detection laser beam to produce the third-order nonlinear optical effect with the nonlinear medium such as rubidium atoms at their resonant wavelength. This is a brand-new four-wave mixing signal light acquisition technology.

[0024] 3) In response to the demand for research and analysis of polarization resolution and spatial three-dimensional resolution of substances with poor photostability (or irreversible processes), the present invention proposes the use of a single laser to achieve multi-polarization resolution calibration, that is, to obtain the polarization-resolved spectrum of the substance from the signal image by utilizing the relationship between the polarization direction and the spatial position. This provides a new technology for studying the polarization direction and structural changes of molecules in substances with poor photostability or irreversible processes, and has broad prospects for promotion and application.

[0025] 4) The device of the present invention has a simple structure, convenient operation, reasonable design, low cost and is easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the single-shot polarization-resolved spectroscopy device based on vector light field according to the present invention;

[0027] Figure 2 Schematic diagram of the fast axis distribution of each half-wave plate in the potential vortex half-wave plate composition;

[0028] Figure 3 Schematic diagram of the polarization direction distribution of the radial vector light field, angular vector light field and mixed vector light field generated by the vortex half-wave plate;

[0029] Figure 4 A schematic diagram of the geometric optical path for focusing the detection laser beam, the first pump laser beam and the second pump laser beam on the atomic and molecular vapor absorption chamber;

[0030] Figure 5 It is the degenerate four-wave mixing energy level transition process.

[0031] The meaning of each reference numeral in the figure:

[0032] 1—laser; 2—first half-wave plate; 3—first polarization splitter cube; 4—first reflector; 5—second half-wave plate; 6—second polarization splitter cube; 7—third half-wave plate; 8—second reflector; 9—fourth half-wave plate; 10—third reflector; 11—fourth reflector; 12—vortex half-wave plate; 13—third polarization splitter cube; 14—focusing lens; 15—atomic and molecular vapor absorption chamber; 16—imaging device. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings so that those skilled in the art can understand the present invention more clearly, but the protection scope of the present invention is not limited thereby.

[0034] The optical path structure for single-shot polarization-resolved spectroscopy based on vector light field of the present invention is as shown in the attached figure. Figure 1 As shown, the single-shot polarization-resolved spectroscopy device based on vector light field of the present invention specifically comprises: a laser 1, a first half-wave plate 2, a first polarization beam splitter cube 3, a first reflector 4, a second half-wave plate 5, a second polarization beam splitter cube 6, a third half-wave plate 7, a second reflector 8, a fourth half-wave plate 9, a third reflector 10, a fourth reflector 11, a vortex half-wave plate 12, a third polarization beam splitter cube 13, a focusing lens 14, an atomic and molecular vapor absorption chamber 15 and an imaging device 16. The laser 1, the first half-wave plate 2, the first polarization beam splitter cube 3, the second half-wave plate 5, the second polarization beam splitter cube 6, the third half-wave plate 7, and the second reflector 8 are sequentially arranged on the same straight optical path. The single-shot polarization-resolved spectroscopy device based on vector light field is composed of the above-mentioned optical elements to form a light source unit, a detection optical path unit, a first pump optical path unit, a second pump optical path unit and a four-wave mixing signal generating unit. The composition structure of each unit is given in detail below, and each unit may share the same optical element. This is because different units utilize different functional parts of the same optical element or separate different light beam parts of the same optical element.

[0035] 1. Light source unit

[0036] The light source unit includes a laser 1 and a first half-wave plate 2. The laser 1 is used to provide a laser beam output. Specifically, the laser beam output by the laser is a linearly polarized Gaussian laser beam, which can be split into a horizontal polarization state and a vertical polarization state. Preferably, the laser 1 is a femtosecond pulse titanium sapphire laser with an output wavelength of 780nm and a power of 200mW. The wavelength of the laser beam generated by the laser is at the absorption wavelength of rubidium atoms in the atomic molecular vapor absorption chamber. The pump laser beam and the detection laser beam generated by the laser 1 are both linearly polarized Gaussian beams.

[0037] The first half-wave plate 2 is arranged on the output optical path of the laser. The half-wave plate is an optical element well known in the art and can rotate the linearly polarized light. Since the linearly polarized light is incident vertically to the half-wave plate, the transmitted light is still linearly polarized light. If the angle between the vibration plane and the main cross section of the crystal is θ at the time of incidence, the vibration plane of the transmitted linearly polarized light rotates by 2θ from the original orientation. In this optical path, the first half-wave plate 2 is rotated to change the splitting ratio of the horizontal polarization state and the vertical polarization state of the laser beam output by the laser after passing through the first polarization splitter cube 3. As described below, the polarization splitter cube transmits a light beam of one polarization state (such as the horizontal polarization state) and reflects a light beam of another polarization state (such as the vertical polarization state). By rotating the half-wave plate, the polarization direction of the linearly polarized laser beam incident on the polarization splitter cube can be changed, thereby changing the splitting ratio of the two polarization beams of polarization states perpendicular to each other that are separated by the polarization splitter cube from the incident linear polarized light. Specifically, in this optical path, the polarization direction of the linear polarized light output by the laser is adjusted by rotating the first half-wave plate 2, thereby adjusting the splitting power ratio of the horizontally polarized pump laser beam and the vertically polarized detection laser beam separated by the first polarization splitter cube 3 from the linear polarized light, thereby achieving the purpose of simultaneously changing the intensity of the pump laser beam and the detection laser beam.

[0038] 2. Detection optical path unit

[0039] The detection optical path unit includes a first polarization beam splitter cube 3, a first reflector 4 and a vortex half-wave plate 12. Specifically, the beam output end of the laser 1 is directly opposite to the beam incident end of the first polarization beam splitter cube 3, the beam reflection output end of the first polarization beam splitter cube 3 is directly opposite to the beam incident end of the first reflector 4, and the beam reflection end of the first reflector 4 is directly opposite to the vortex half-wave plate 12. The optical characteristics of each optical element in the detection optical path unit and its role in the optical path are as follows:

[0040] The optical characteristics of the first polarization splitter cube 3 are: beam splitting based on the different polarization states of the light beams. Specifically, the first polarization splitter cube 3 transmits the light beam in the horizontal polarization direction and reflects the light beam in the vertical polarization direction. In the optical path, the function of the first polarization splitter cube 3 is to split the laser beam output by the laser into a pump laser beam and a detection laser beam. Specifically, the horizontal polarization component in the laser beam is transmitted and output to the pump optical path unit, and the vertical polarization component in the laser beam is vertically reflected and output to the detection optical path unit. In this way, after the beams are split by the first polarization splitter cube 3, a horizontally polarized pump laser beam and a vertically polarized detection laser beam that are transmitted perpendicular to each other are obtained.

[0041] The first reflector 4 can provide 90° reflection for the detection laser beam.

[0042] The optical property of the vortex half-wave plate 12 is to change the radial and angular polarization distribution of the light field, and its role in the detection optical path unit is to convert the incident detection laser beam from linearly polarized light into a vector light field. The vortex half-wave plate 12 is preferably a vortex wave plate formed by splicing a plurality of fan-shaped half-wave plates, and the fast axis directions of the preferred half-wave plates are uniformly arranged according to the rule of deflecting 2mπ angles around the circumference. Each half-wave plate deflects the polarization direction of the incident laser beam accordingly based on its fast axis direction, so that the polarization direction of the light beam at different positions in the cross section of the linearly polarized Gaussian light can be deflected at different angles through the vortex half-wave plate. Preferred examples are as follows: Figure 2 The vortex half-wave plate shown in the figure, where the direction of the arrow represents the fast axis direction of each fan-shaped half-wave plate, after the linearly polarized detection laser passes through the vortex half-wave plate, the fast axis direction of the half-wave plate corresponding to each part of the linear polarized light in the detection beam cross section is different, so that the polarization direction of this part of the linear polarized light is deflected at different angles (twice the fast axis deflection angle of the half-wave plate), which can produce the following Figure 3 Radially polarized light is shown.

[0043] Therefore, according to the different splicing methods of the half-wave plates in the vortex half-wave plate, the linearly polarized light of the incident detection laser beam can generate radial vector light field, angular vector light field and mixed vector light field containing radial polarization and angular polarization after passing through the vortex half-wave plate, as shown in the attached figure. Figure 3 In the present invention, the vortex half-wave plate is preferably used to convert the detection laser beam from a linear polarization state to Figure 3 The radial vector light field shown in the figure, the radial vector light field generated by the vortex half-wave plate 12 contains linear polarization states of all different directions, so the single-shot polarization-resolved spectroscopy technology can be directly implemented.

[0044] The light beam transmission process in the detection optical path unit is as follows: the linearly polarized laser beam output by the laser 1 is incident on the first polarization beam splitter cube 3 in a linear polarization state after the polarization direction is adjusted by the first half-wave plate 2, wherein the vertical polarization component is reflected and output by the first polarization beam splitter cube 3 to form a detection laser beam with a vertical polarization state, and the detection laser beam is further vertically reflected by the first reflector 4 to the vortex half-wave plate 12, and the vertically polarized detection laser beam passes through the vortex half-wave plate 12 to form a radial vector light field containing linear polarization states in different directions, and the radial vector light field is output to the four-wave mixing signal generating unit.

[0045] 3. The first pump optical path unit

[0046] The first pump optical path unit includes a first polarization splitter cube 3, a second half-wave plate 5, a second polarization splitter cube 6, a third half-wave plate 7, a second reflector 8 and a third polarization splitter cube 13. The beam transmission output end of the first polarization splitter cube 3 is arranged opposite to the beam incident end of the second polarization splitter cube 6. The second half-wave plate 5 is arranged between the beam transmission output end of the first polarization splitter cube 3 and the beam incident end of the second polarization splitter cube 6. The beam transmission output end of the second polarization splitter cube 6 is arranged opposite to the beam incident end of the second reflector 8. The third half-wave plate 7 is arranged between the beam transmission output end of the second polarization splitter cube 6 and the beam incident end of the second reflector 8. The beam reflection end of the second reflector 8 is arranged opposite to the beam incident end of the third polarization splitter cube 13.

[0047] The optical characteristics of each optical element in the first pump optical path unit and the role it plays in the optical path are as follows:

[0048] The optical characteristics of the first polarization splitter cube 3 are: beam splitting based on the different polarization states of the light beams. Specifically, the first polarization splitter cube 3 transmits the light beam in the horizontal polarization direction and reflects the light beam in the vertical polarization direction. In the optical path, the function of the first polarization splitter cube 3 is to split the laser beam output by the laser into a pump laser beam and a detection laser beam. Specifically, the horizontal polarization component in the laser beam is transmitted and output to the pump optical path unit, and the vertical polarization component in the laser beam is vertically reflected and output to the detection optical path unit. In this way, after the beams are split by the first polarization splitter cube 3, a horizontally polarized pump laser beam and a vertically polarized detection laser beam that are transmitted perpendicular to each other are obtained.

[0049] The second half-wave plate 5 is arranged directly behind the first polarization beam splitter cube 3. The second half-wave plate has the same function as the first half-wave plate, and can rotate and adjust the polarization direction of the linear polarized light. Based on the optical characteristics of the half-wave plate in this optical path, the linear polarization direction of the pump laser beam transmitted and output by the first polarization beam splitter cube 3 can be adjusted by rotating the second half-wave plate 5, so that its polarization direction deviates from the horizontal direction, so that the pump laser beam can be separated into the horizontal polarization component and the vertical polarization component again after passing through the second polarization beam splitter cube 6, and the power can be adjusted when polarization beam splitting is performed.

[0050] The second polarization beam splitter cube 6 is the same as the first polarization beam splitter cube, and can perform beam splitting based on the different polarization states of the beams. Specifically, the second polarization beam splitter cube 6 transmits the beam in the horizontal polarization direction and reflects the beam in the vertical polarization direction. In this optical path, the pump laser beam whose polarization direction deviates from the horizontal direction after the second half-wave plate 5 is acted upon is split into a pump laser beam with a horizontal polarization state again after passing through the second polarization beam splitter cube 6. The pump laser beam with a horizontal polarization state serves as the first pump laser beam in the first pump optical path unit. At the same time, the power of the first horizontally polarized pump laser beam is reduced relative to the power of the total horizontally polarized pump laser beam after passing through the first polarization beam splitter cube 3, which is equivalent to adjusting the power of the pump laser beam. At the same time, the pump laser beam whose polarization direction deviates from the horizontal direction after the second half-wave plate 5 is acted upon is reflected by the second polarization beam splitter cube 6 and can be split into a pump laser beam with a vertical polarization state. The vertically polarized pump laser beam serves as the second pump laser beam in the second pump optical path unit. Therefore, the ratio of the pump laser beam split into the second pump optical path unit and the first pump optical path unit can be adjusted by rotating and adjusting the second half-wave plate 5 in combination with the second polarization splitter cube 6 .

[0051] The third half-wave plate 7 is arranged at the transmission output end of the second polarization beam splitter cube 6. The third half-wave plate has the same function as the second half-wave plate, and can rotate and adjust the polarization direction of the linear polarized light. Based on the optical characteristics of the half-wave plate in this optical path, the linear polarization direction of the first pump laser beam with a horizontal polarization state transmitted and output by the second polarization beam splitter cube 6 can be adjusted by rotating the third half-wave plate 7, so that its polarization direction deviates from the horizontal direction again, thereby enabling the first pump laser beam to be separated into a vertical polarization component after passing through the third polarization beam splitter cube 13, and realizing the power adjustment when performing polarization beam splitting.

[0052] The second reflector 8 can provide 90° reflection for the first pump laser beam.

[0053] The third polarization beam splitter cube 13 is the same as the second polarization beam splitter cube, and can perform beam splitting based on the different polarization states of the beams. Specifically, the third polarization beam splitter cube 13 transmits the beam in the horizontal polarization direction and reflects the beam in the vertical polarization direction. In this optical path, after the first pump laser beam whose polarization direction deviates from the horizontal direction after the third half-wave plate 7 is incident on the third polarization beam splitter cube 13, it is reflected and output by the third polarization beam splitter cube 13 to output the vertical polarization component in the first pump laser beam, that is, the vertical polarization component in the first pump laser beam is reflected and split to the four-wave mixing signal generating unit by the third polarization beam splitter cube 13. The horizontal polarization component in the first pump laser beam is collected after passing through the third polarization beam splitter cube 13. By rotating and adjusting the third half-wave plate 7 and combining the third polarization beam splitter cube 13, the power of the first pump laser beam split to the four-wave mixing signal generating unit can be adjusted separately.

[0054] The beam transmission process in the first pump optical path unit is as follows: after the laser beam output by the laser 1 is polarized by the first half-wave plate 2, it is still incident on the first polarization beam splitter cube 3 in a linear polarization state, wherein the horizontal polarization component is transmitted and output by the first polarization beam splitter cube 3 to form a total pump laser beam with a horizontal polarization state, and the total pump laser beam is polarized by the second half-wave plate 5 to form a total pump laser beam with both a horizontal polarization state and a vertical polarization state, and the total pump laser beam is incident on the second polarization beam splitter cube 6, wherein the horizontal polarization component is transmitted and output by the second polarization beam splitter cube 6 to form a first pump laser beam with a horizontal polarization state, wherein the vertical polarization component is reflected and output by the second polarization beam splitter cube 6 to form a second pump laser beam with a vertical polarization state, and the splitting ratio of the first pump laser beam and the second pump laser beam is adjusted by the second half-wave plate 5 and the second polarization beam splitter cube 6. The first pump laser beam with a horizontal polarization state is converted again from a horizontal polarization state to a state having both a horizontal polarization state and a vertical polarization state after passing through the third half-wave plate 7, and then is reflected toward the third polarization splitter cube 13 by the second reflector. The vertical polarization component of the first pump laser beam is reflected and output to the four-wave mixing signal generating unit through the third polarization splitter cube 13. The power of the first pump laser beam split into the four-wave mixing signal generating unit is adjusted individually by rotating and adjusting the third half-wave plate 7 and combining with the third polarization splitter cube 13.

[0055] 4. Second Pump Optical Path Unit

[0056] The second pump optical path unit includes a second polarization splitter cube 6, a fourth half-wave plate 9, a third reflector 10, a fourth reflector 11 and a third polarization splitter cube 13. The beam reflection output end of the second polarization splitter cube 6 is arranged opposite to the beam incident end of the third reflector 10. The fourth half-wave plate 9 is arranged between the beam reflection output end of the second polarization splitter cube 6 and the beam incident end of the third reflector 10. The beam reflection end of the third reflector 10 is arranged opposite to the beam incident end of the fourth reflector 11. The beam reflection end of the fourth reflector 11 is arranged opposite to the beam incident end of the third polarization splitter cube 13.

[0057] The optical characteristics of each optical element in the second pump optical path unit and the role it plays in the optical path are as follows:

[0058] The second polarization beam splitter cube 6 is the same as described above, transmitting the light beam in the horizontal polarization direction and reflecting the light beam in the vertical polarization direction. After the second half-wave plate 5 acts, the total pump laser beam whose polarization direction deviates from the horizontal direction is reflected by the second polarization beam splitter cube 6 to separate the pump laser beam with the vertical polarization state, and the vertically polarized pump laser beam is used as the second pump laser beam in the second pump optical path unit. The splitting ratio of the first pump laser beam and the second pump laser beam is adjusted by rotating the second half-wave plate 5 and combining with the second polarization beam splitter cube 6.

[0059] The fourth half-wave plate 9 is arranged at the reflection output end of the second polarization beam splitter cube 6. The fourth half-wave plate has the same function as the third half-wave plate, and can rotate and adjust the polarization direction of the linear polarized light. In this optical path, by rotating the fourth half-wave plate 9, the linear polarization direction of the second pump laser beam with a vertical polarization state reflected and output by the second polarization beam splitter cube 6 can be adjusted, so that its polarization direction deviates from the vertical direction, thereby making it possible to adjust the power of the vertical polarization component of the second pump laser beam reflected and separated after passing through the third polarization beam splitter cube 13.

[0060] The third reflecting mirror 10 can provide 90° reflection for the second pump laser beam.

[0061] The fourth reflecting mirror 11 can provide 90° reflection for the second pump laser beam.

[0062] The third polarization beam splitter cube 13 is the same as described above, transmitting the light beam in the horizontal polarization direction and reflecting the light beam in the vertical polarization direction. The vertical polarization component in the second pump laser beam incident on the third polarization beam splitter cube 13 is reflected and split by the third polarization beam splitter cube 13 to the four-wave mixing signal generating unit, and the horizontal polarization component in the second pump laser beam is collected after passing through the third polarization beam splitter cube 13. The power of the second pump laser beam split to the four-wave mixing signal generating unit can be adjusted separately by rotating and adjusting the fourth half-wave plate 9 and combining with the third polarization beam splitter cube 13.

[0063] The beam transmission process in the second pump optical path unit is as follows: the total pump laser beam is reflected and output by the second polarization splitter cube 6 to produce a second pump laser beam with a vertical polarization state, and after passing through the fourth half-wave plate 9, its polarization state is converted again from a vertical polarization state to a horizontal polarization state and a vertical polarization state at the same time, and then reflected to the third polarization splitter cube 13 through the third reflector 10 and the fourth reflector 11, and the vertical polarization component of the second pump laser beam is reflected and output to the four-wave mixing signal generating unit through the third polarization splitter cube 13. By rotating and adjusting the fourth half-wave plate 9 and combining with the third polarization splitter cube 13, the power of the second pump laser beam split into the four-wave mixing signal generating unit can be individually adjusted.

[0064] 5. Four-wave mixing signal generation unit

[0065] The four-wave mixing signal generating unit includes a focusing lens 14, an atomic and molecular vapor absorption chamber 15 and an imaging device 16, wherein the focusing lens 14, the atomic and molecular vapor absorption chamber 15 and the imaging device 16 are arranged in sequence on the same straight optical path, wherein the atomic and molecular vapor absorption chamber 15 is located between the focusing lens 14 and the imaging device 16.

[0066] The optical characteristics of each optical element in the four-wave mixing signal generating unit and its role in the optical path are as follows:

[0067] The focusing lens 14 is arranged facing the beam output ends of the detection optical path unit, the first pumping optical path unit and the second pumping optical path unit. The detection laser beam from the detection optical path unit, the first pumping laser beam from the first pumping optical path unit and the second pumping laser beam from the second pumping optical path unit are focused by the focusing lens and incident on the atomic molecular vapor absorption chamber 15. Preferably, the detection laser beam, the first pumping laser beam and the second pumping laser beam are incident on the focusing lens in parallel with each other, and the three laser beams are respectively located at the three vertices of the square on the optical path cross section before incident on the focusing lens 14. The three laser beams are focused to the center position in the atomic molecular vapor absorption chamber 15 by the focusing lens 14. This optical path geometry can well meet the forward degenerate four-wave mixing configuration requirements, as shown in the attached Figure 4 As shown, the three laser beams are strictly located at the three vertices of the square, which can improve the efficiency of generating four-wave mixing signals.

[0068] The atomic and molecular vapor absorption chamber 15 is a rubidium atomic vapor absorption chamber, and its absorption wavelength is at the wavelength of the laser beam output by the laser. The rubidium atomic vapor generates a four-wave mixing signal through a third-order nonlinear effect with the pump laser beam and the detection laser beam.

[0069] The imaging device 16 includes a CCD camera or a CMOS camera, which is used to observe and record the four-wave mixing signal in real time.

[0070] The following is a brief description of the principle of four-wave mixing signal generation. The four-wave mixing effect refers to the process in which three incident light waves with the same or different frequencies and wave vectors generate a fourth coherent light wave in the medium, and these four light waves interact with each other in the medium. It is caused by the third-order nonlinear polarizability of the medium. The reason for four-wave mixing is that light of a certain wavelength in the incident light will change the refractive index of the nonlinear medium, which will produce a change in the phase of the light waves at different frequencies, thereby generating light waves of new wavelengths. If the three incident light waves have equal frequencies, the frequency of the generated fourth coherent light wave will also be the same as the frequency of the incident light waves. We call this interaction process degenerate four-wave mixing, and the present invention is preferably directed to degenerate four-wave mixing.

[0071] superior Figure 5 is the degenerate four-wave mixing process in a two-level system, where E1 and E2 are called pump fields, E3 is called the detection field, and E4 is the degenerate four-wave mixing signal. For degenerate four-wave mixing, from the phase matching condition k4=k1+k2-k3, it can be seen that the forward degenerate four-wave mixing signal propagates along the fourth diagonal of the forward degenerate four-wave mixing configuration space regular prism. In the interaction between light and atoms, the response of atoms to the light field mainly depends on the transition in their energy level system that resonates with the incident light field.

[0072] The following is a single-shot polarization-resolved spectroscopy method based on a vector light field, that is, a specific operation implementation method of the single-shot polarization-resolved spectroscopy device of the present invention. Before describing the method, the starting point of the invention of this patent is briefly described. As mentioned above, the nonlinear optical signal is radiated by the vibration of a nonlinearly polarized dipole. For nonlinear medium molecules that have a certain orientation, the direction of their dipole moment will affect the nonlinear polarization direction caused by the incident light, thereby changing the polarization direction of the nonlinear optical signal in turn. Different nonlinear media have different molecular orientations, which will cause different polarization directions of the nonlinear optical signal. That is, by changing the polarization state of the incident light and detecting the polarization and intensity of the corresponding radiation light (nonlinear optical signal), the orientation of the nonlinear medium molecules can be detected. In the prior art, the spectral resolution of a nonlinear medium is to allow the detection light of different polarization states to be incident on the nonlinear medium, and detect the corresponding polarization direction and intensity of the signal light generated based on the four-wave mixing effect to distinguish the nonlinear medium. The spectral resolution of a nonlinear medium needs to be simultaneously based on the four-wave mixing signals of multiple detection lights of different polarization states for resolution. In the prior art, when performing nonlinear molecular orientation spectral resolution detection, the acquisition of multiple beams of detection light with different polarization states is achieved by replacing different detection light sources. Such frequent replacement of detection light sources will result in the inability to guarantee detection accuracy and very inconvenient operation. The present invention innovatively realizes the simultaneous generation of detection light sources and pump light sources based on a single light source, and the simultaneous generation of detection incident light with different polarization states based on a single detection light source, thereby realizing the detection light sources with different polarization states required for resolving nonlinear media. Specifically, the single-shot polarization resolution spectroscopy method based on a vector light field described in the present invention includes the following steps:

[0073] Step 1: The laser beam generated by the laser 1 passes through the first half-wave plate 2 and the first polarization beam splitter cube 3 in sequence and is split into two beams of light, wherein the laser beam passing through the first polarization beam splitter cube 3 is a pump laser beam with a horizontal polarization state, and the laser beam reflected by the first polarization beam splitter cube 3 is a detection laser beam with a vertical polarization state; the splitting ratio of the pump laser beam and the detection laser beam is adjusted by rotating the first half-wave plate 2;

[0074] Step 2, wherein the detection laser beam reflected and split by the first polarization splitting cube 3 passes through the first reflector 4 and the vortex half-wave plate 12 in sequence and is focused by the focusing lens 14 to the atomic and molecular vapor absorption chamber 15, wherein the detection laser beam passes through the vortex half-wave plate 12 to form a radial vector light field with multiple different polarization directions;

[0075] Step 3, wherein the total pump laser beam transmitted and split by the first polarization splitter cube 3 is sequentially split into two pump laser beams through the second half-wave plate 5 and the second polarization splitter cube 6, wherein the pump laser beam transmitted through the second polarization splitter cube 6 is a first pump laser beam with a horizontal polarization state, and the pump laser beam reflected by the second polarization splitter cube 6 is a second pump laser beam with a vertical polarization state; the splitting ratio of the first pump laser beam and the second pump laser beam is adjusted by rotating the second half-wave plate 5;

[0076] Step 4, wherein the first pump laser beam is focused to the atomic and molecular vapor absorption chamber 15 through the third half-wave plate 7, the second reflector 8, the third polarization splitter cube 13 and the focusing lens 14 in sequence, and the first pump laser beam reflected by the third polarization splitter cube 13 has a vertical polarization state, and the power of the first pump laser beam incident to the atomic and molecular vapor absorption chamber is adjusted by rotating the third half-wave plate; wherein the second pump laser beam is focused to the atomic and molecular vapor absorption chamber 15 through the fourth half-wave plate 9, the third reflector 10, the fourth reflector 11, the third polarization splitter cube 13 and the focusing lens 14 in sequence, and the second pump laser beam has a vertical polarization state after being reflected by the third polarization splitter cube 13, and the power of the second pump laser beam incident to the atomic and molecular vapor absorption chamber is adjusted by rotating the fourth half-wave plate.

[0077] Step 5, adjusting the emission positions of the detection laser beam, the first pump laser beam and the second pump laser beam by adjusting the first reflector 4, the second reflector 8, the third reflector 10, the fourth reflector 11, the third polarization beam splitter cube 13 and other components, so that the three laser beams are located at three vertices of a square in the optical path section before the focusing lens 14, and are focused on a point in the atomic and molecular vapor absorption chamber 15 after passing through the focusing lens 14;

[0078] Step 6: Adjust the power of the three laser beams of the laser and the concentration of rubidium atoms in the atomic and molecular vapor absorption chamber 15 so that an obvious four-wave mixing signal light appears on the imaging device 16, wherein the method for adjusting the power of the laser beam is to adjust the angle of the first half-wave plate 2, and by changing the distribution of the horizontal polarization state and vertical polarization state components of the incident light, change the transmission and reflection component distribution of the incident light passing through the first polarization beam splitting cube 3, thereby changing the component distribution of the pump laser beam and the detection laser beam. The power of the detection laser beam, the first pump laser beam and the second pump laser beam are changed separately by rotating the second half-wave plate 5, the third half-wave plate 7 and the fourth half-wave plate 9, wherein the method for changing the concentration of rubidium atoms is to adjust the voltage of the heating belt of the atomic and molecular vapor absorption chamber 15, and change the temperature of the heating belt by adjusting the voltage of the heating belt, thereby adjusting the temperature in the atomic and molecular vapor absorption chamber 15. Rotate the vortex half-wave plate 12 so that the detection laser beam passing through the vortex half-wave plate 12 is a radial vector light field, and then obtain the four-wave mixing signal light on the imaging device 16.

[0079] Step seven, then keep the power of the first pump laser beam and the second pump laser beam incident into the atomic and molecular vapor absorption chamber 15 constant, then dynamically adjust the polarization state of the detection laser beam incident into the atomic and molecular vapor absorption chamber 15, add a linear polarizer between the vortex half-wave plate 12 and the focusing lens 14, when the polarizer is 0°, the detection laser beam incident into the atomic and molecular vapor absorption chamber 15 through the focusing lens has a vertical polarization state, and the imaging device 16 records the light spot and polarization state of the four-wave mixing signal light obtained at this time; when the polarizer is 45°, the detection laser beam incident into the atomic and molecular vapor absorption chamber 15 through the focusing lens is in a polarization state of 45° counterclockwise, and the imaging device 16 records the light spot and polarization state of the four-wave mixing signal light obtained at this time. The spot and polarization state of the four-wave mixing signal light; when the polarizer is 90°, the detection laser beam incident into the atomic molecular vapor absorption chamber 15 through the focusing lens is in a horizontal polarization state, and the imaging device 16 records the spot and polarization state of the four-wave mixing signal light obtained at this time; when the polarizer is 135°, the detection laser beam incident into the atomic molecular vapor absorption chamber 15 through the focusing lens is in a counterclockwise polarization state of 135°, and the imaging device 16 records the spot and polarization state of the four-wave mixing signal light obtained at this time; when the polarizer is 180°, the detection laser beam incident into the atomic molecular vapor absorption chamber 15 through the focusing lens is in a vertical polarization state, and the imaging device 16 records the spot and polarization state of the four-wave mixing signal light obtained at this time.

[0080] Step 8: Use an imaging device to record the light spots and polarization states of the corresponding four-wave mixing signal light generated by the atomic and molecular vapor absorption chamber 15 based on the detection laser beams of multiple polarization states, and use this comprehensive spectrum information as the spectral resolution calibration standard of the specific nonlinear medium in the atomic and molecular vapor absorption chamber 15. Using multiple polarization states to simultaneously resolve improves the resolution accuracy.

[0081] This invention innovatively uses vector light fields for polarization-resolved spectroscopy, effectively making up for the inability of existing multi-shot four-dimensional resolution (polarization resolution + spatial three-dimensional resolution) four-wave mixing spectroscopy to effectively study irreversible processes, and will become an important means of obtaining all information about polar molecules in polarization and space. This single-shot polarization-resolved spectroscopy based on vector light fields is expected to clarify the physical mechanism of the interaction between polarized light and biological polar molecules, which provides a theoretical basis for laser medical treatment.

[0082] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A single-shot polarization-resolved spectroscopy device based on vector light field, characterized in that: include: A laser (1), a first half-wave plate (2), a first polarization beam splitter cube (3), a first reflector (4), a second half-wave plate (5), a second polarization beam splitter cube (6), a third half-wave plate (7), a second reflector (8), a fourth half-wave plate (9), a third reflector (10), a fourth reflector (11), a vortex half-wave plate (12), a third polarization beam splitter cube (13), a focusing lens (14), an atomic and molecular vapor absorption chamber (15), and an imaging device (16); wherein the laser (1) and the first half-wave plate (2) are composed A light source unit for generating a laser beam; a detection optical path unit composed of the first polarization beam splitter cube (3), a first reflector (4) and a vortex half-wave plate (12) for generating a detection laser beam; a first pump optical path unit composed of the first polarization beam splitter cube (3), a second half-wave plate (5), a second polarization beam splitter cube (6), a third half-wave plate (7), a second reflector (8) and a third polarization beam splitter cube (13) for generating a first pump laser beam; a detection optical path unit composed of the first polarization beam splitter cube (3), a second half-wave plate (5), a second polarization beam splitter cube (6), a third half-wave plate (7), a second reflector (8) and a third polarization beam splitter cube (13) for generating a first pump laser beam; The reflector (10), the fourth reflector (11) and the third polarization beam splitting cube (13) form a second pump optical path unit for generating a second pump laser beam; the focusing lens (14), the atomic and molecular vapor absorption chamber (15) and the imaging device (16) form a four-wave mixing signal generating unit, and the detection laser beam, the first pump laser beam and the second pump laser beam generate a four-wave mixing signal in the four-wave mixing signal generating unit; the laser (1) in the light source unit is a femtosecond pulse titanium sapphire laser, and the output laser beam is a linearly polarized state. A Gaussian laser beam, wherein the output laser center wavelength is at the absorption wavelength of the atomic molecular vapor absorption chamber (15); the first pump laser beam and the second pump laser beam incident into the atomic molecular vapor absorption chamber (15) have a vertical polarization state; the detection laser beam is a radial vector light field containing multiple polarization directions, the polarization state of the detection laser beam can be adjusted by a polarizing plate, and corresponding to different polarization states of the detection laser beam, the atomic molecular vapor absorption chamber (15) generates a corresponding four-wave mixing signal capable of calibrating the orientation of nonlinear medium molecules therein.

2. The single-shot polarization-resolved spectroscopy device according to claim 1, characterized in that: The first polarization beam splitter cube (3), the second polarization beam splitter cube (6) and the third polarization beam splitter cube (13) transmit laser beams with a horizontal polarization direction and reflect laser beams with a vertical polarization direction; the first half-wave plate (2), the second half-wave plate (5), the third half-wave plate (7) and the fourth half-wave plate (9) are capable of rotationally adjusting the polarization direction of polarized light; the first half-wave plate (2) and the first polarization beam splitter cube (3) are used to adjust the beam splitting ratio of the pump laser beam and the detection laser beam; the second half-wave plate (5) and the second polarization beam splitter cube (6) are used to adjust the beam splitting ratio of the first pump laser beam and the second pump laser beam; the third half-wave plate (7) and the third polarization beam splitter cube (13) are used to adjust the power of the first pump laser beam incident on the atomic and molecular vapor absorption chamber (15); and the fourth half-wave plate (9) and the third polarization beam splitter cube (13) are used to adjust the power of the second pump laser beam incident on the atomic and molecular vapor absorption chamber (15).

3. The single-shot polarization-resolved spectroscopy device according to claim 2, characterized in that: The laser (1), the first half-wave plate (2), the first polarization beam splitter cube (3), the second half-wave plate (5), the second polarization beam splitter cube (6), the third half-wave plate (7) and the second reflector (8) are sequentially arranged on the same straight optical path; the laser beam generated by the laser (1) passes through the first half-wave plate (2) and is incident on the first polarization beam splitter cube (3); the laser beam transmitted through the first polarization beam splitter cube (3) is output as a pump laser beam with a horizontal polarization state; the laser beam reflected through the first polarization beam splitter cube (3) is output as a detection laser beam with a vertical polarization state; the detection laser beam passes through the vortex half-wave plate (12) to generate a radial vector light field containing multiple polarization directions; the pump laser beam passes through the second half-wave plate (5) and is incident on the second polarization beam splitter cube (6); the laser beam transmitted through the second polarization beam splitter cube (6) is output as a first pump laser beam with a horizontal polarization state; the laser beam reflected through the second polarization beam splitter cube (6) is output as a first pump laser beam with a vertical polarization state. a second pump laser beam; the first pump laser beam is incident on the third polarization beam splitter cube (13) after passing through the third half-wave plate (7) and the second reflector (8); the vertical component of the first pump laser beam having a vertical polarization state is output after being reflected by the third polarization beam splitter cube (13); the second pump laser beam is incident on the third polarization beam splitter cube (13) after passing through the fourth half-wave plate (9), the third reflector (10) and the fourth reflector (11); the vertical component of the second pump laser beam having a vertical polarization state is output after being reflected by the third polarization beam splitter cube (13); the radial vector light field, the vertical component of the first pump laser beam and the vertical component of the second pump laser beam are focused in the atomic and molecular vapor absorption chamber (15) through a focusing lens (14); and the radial vector light field, the vertical component of the first pump laser beam and the vertical component of the second pump laser beam are respectively located at three vertices of a square on the optical path section before the focusing lens (14).

4. The single-shot polarization-resolved spectroscopy device according to claim 2 or 3, characterized in that: In the detection optical path unit, the beam incident end of the first polarization beam splitter cube (3) is arranged opposite to the beam output end of the laser, the beam reflection output end of the first polarization beam splitter cube (3) is arranged opposite to the beam incident end of the first reflector (4), and the beam reflection end of the first reflector (4) is arranged opposite to the vortex half-wave plate (12). The beam transmission process in the detection optical path unit is as follows: the laser beam output by the laser (1) is incident on the first polarization beam splitter cube (3) after the polarization direction is adjusted by the first half-wave plate (2), the vertical polarization component in the laser beam is reflected by the first polarization beam splitter cube (3) as a detection laser beam and output to the first reflector (4), and is vertically reflected by the first reflector (4) to the vortex half-wave plate (12), and the detection laser beam forms a radial vector light field containing linear polarization states in different directions after passing through the vortex half-wave plate (12).

5. The single-shot polarization-resolved spectroscopy device according to claim 4, characterized in that: The vortex half-wave plate (12) is formed by splicing a plurality of fan-shaped half-wave plates, and the fast axis directions of the respective half-wave plates are evenly arranged according to a rule of deflection of 2mπ angles around a circle, where m is an integer. Each half-wave plate causes a corresponding deflection of the polarization direction of the incident laser beam based on its fast axis direction, and the laser beams at different positions passing through the vortex half-wave plate are polarized at different angles, and finally the laser beam emitted through the vortex half-wave plate (12) forms a radial vector light field containing linear polarization states in different directions.

6. The single-shot polarization-resolved spectroscopy device according to claim 5, characterized in that: In the first pump optical path unit, the light beam transmission output end of the first polarization beam splitter cube (3) is arranged opposite to the light beam incident end of the second polarization beam splitter cube (6), the second half-wave plate (5) is arranged between the first polarization beam splitter cube (3) and the second polarization beam splitter cube (6), the light beam transmission output end of the second polarization beam splitter cube (6) is arranged opposite to the light beam incident end of the second reflector (8), the third half-wave plate (7) is arranged between the second polarization beam splitter cube (6) and the second reflector (8), and the light beam reflection end of the second reflector (8) is arranged opposite to the light beam incident end of the third polarization beam splitter cube (13); the light beam transmission process of the first pump optical path unit is as follows: the laser beam output by the laser (1) passes through the first half-wave plate (2) and enters After adjusting the horizontal polarization direction, the laser beam is incident on the first polarization beam splitter cube (3); the horizontal polarization component in the laser beam is transmitted and output by the first polarization beam splitter cube (3) and incident on the second half-wave plate (5) as a pump laser beam; after adjusting the polarization direction by the second half-wave plate (5), the laser beam is incident on the second polarization beam splitter cube (6); the horizontal polarization component in the pump laser beam is transmitted and output by the second polarization beam splitter cube (6) and incident on the third half-wave plate (7) as a first pump laser beam; after adjusting the polarization direction again by the third half-wave plate (7), the laser beam is incident on the second reflector (8) and the third polarization beam splitter cube (13); the vertical polarization component in the first pump laser beam is reflected and output by the third polarization beam splitter cube (13) and output as the vertical component of the first pump laser beam to the four-wave mixing signal generating unit.

7. The single-shot polarization-resolved spectroscopy device according to claim 5, characterized in that: In the second pump optical path unit, the light beam reflection output end of the second polarization beam splitter cube (6) is arranged directly opposite to the light beam incident end of the third reflector (10), the fourth half-wave plate (9) is arranged between the second polarization beam splitter cube (6) and the third reflector (10), the light beam reflection end of the third reflector (10) is arranged directly opposite to the light beam incident end of the fourth reflector (11), and the light beam reflection end of the fourth reflector (11) is arranged directly opposite to the light beam incident end of the third polarization beam splitter cube (13); The light beam transmission process of the second pump optical path unit is as follows: the second pump laser beam with a vertical polarization state reflected and output by the second polarization beam splitter cube (6) is incident on the fourth half-wave plate (9), and after the polarization direction is adjusted by the fourth half-wave plate (9), is incident on the third reflector (10), the fourth reflector (11) and the third polarization beam splitter cube (13); the vertical polarization component in the second pump laser beam is reflected and output by the third polarization beam splitter cube (13), and is output as the second pump laser beam vertical component to the four-wave mixing signal generating unit.

8. A single-shot polarization-resolved spectroscopy method based on the single-shot polarization-resolved spectroscopy device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Start the laser, so that the laser beam generated by the laser (1) passes through the first half-wave plate (2) and the first polarization splitting cube (3) in sequence and is split into a pump laser beam with a horizontal polarization state and a detection laser beam with a vertical polarization state, and the first half-wave plate (2) is rotated to adjust the splitting ratio of the pump laser beam and the detection laser beam to a suitable range; Step 2, wherein the detection laser beam reflected and split by the first polarization splitting cube (3) passes through the first reflector (4) and the vortex half-wave plate (12) in sequence to form a radial vector light field with multiple different polarization directions, and is focused by the focusing lens (14) to the atomic and molecular vapor absorption chamber (15); Step 3, wherein the pump laser beam transmitted and split by the first polarization splitting cube (3) passes through the second half-wave plate (5) and the second polarization splitting cube (6) in sequence and is split into a first pump laser beam with a horizontal polarization state and a second pump laser beam with a vertical polarization state, and the second half-wave plate (5) is rotated to adjust the splitting ratio of the first pump laser beam and the second pump laser beam to an appropriate range; Step 4, wherein the first pump laser beam sequentially passes through the third half-wave plate (7), the second reflector (8), and the third polarization splitter cube (13), and then is focused by the focusing lens (14) on the atomic and molecular vapor absorption chamber (15), and the third half-wave plate is rotated to adjust the power of the first pump laser beam incident on the atomic and molecular vapor absorption chamber to a suitable range; wherein the second pump laser beam sequentially passes through the fourth half-wave plate (9), the third reflector (10), the fourth reflector (11), and the third polarization splitter cube (13), and then is focused by the focusing lens (14) on the atomic and molecular vapor absorption chamber (15), and the fourth half-wave plate is rotated to adjust the power of the second pump laser beam incident on the atomic and molecular vapor absorption chamber to a suitable range; Step 5, continue to adjust the power of the first pump laser beam and the second pump laser beam incident into the atomic and molecular vapor absorption chamber and the atomic and molecular vapor concentration in the atomic and molecular vapor absorption chamber (15) until obvious four-wave mixing signal light appears on the imaging device (16); Step six, then keep the power of the first pump laser beam and the second pump laser beam incident on the atomic and molecular vapor absorption chamber (15) unchanged, dynamically adjust the polarization state of the detection laser beam incident on the atomic and molecular vapor absorption chamber, add a linear polarizer between the vortex half-wave plate and the focusing lens and successively set the linear polarizer at different angles so that the detection laser beam incident on the atomic and molecular vapor absorption chamber has different polarization states, and record the light spot and polarization information of the four-wave mixing signal light obtained under various polarization states through the imaging device (16), so as to obtain the spectral information for distinguishing the nonlinear medium in the atomic and molecular vapor absorption chamber.

Images