An integrated dual-wavelength pumped transient absorption spectrum acquisition system

Abstract

This invention discloses an integrated dual-wavelength pumped transient absorption spectral acquisition system and method. A femtosecond laser outputs femtosecond pulses, which are attenuated by a first beam-splitting system and then proportionally split into a pump optical path and a probe optical path by a second beam-splitting system. The probe optical path is delayed by an optical path delay system before entering a supercontinuum white light generation system to generate broadband white light. Noise is then filtered out by a first filtering system, and the light is focused onto the sample by a first converging system. The pump optical path is modulated by a chopper system and frequency-doubled by a wavelength conversion system, purified by a second filtering system, and focused by a second converging system to overlap collinearly with the probe light at the sample. The emitted light is collected by a third converging system and processed by a signal acquisition system. This invention overcomes the shortcomings of existing technologies in achieving precise dual-wavelength measurement of ultrafast material dynamics in a stable, interference-free environment.

Description

Technical Field

[0001] This invention relates to ultrafast spectroscopy, specifically to a transient absorption spectroscopy acquisition and method integrating dual-wavelength pumping. Background Technology

[0002] Transition metal chalcogenides (TMDCs) can exhibit a variety of crystal phases and possess different structures, symmetries, and physical properties due to the different spatial coordination of transition metal atoms. Optical methods are important for studying the band structure and carrier relaxation processes of materials. Transient absorption spectroscopy can detect the ultrafast dynamic processes of materials after photoexcitation in real time, and is an effective tool for studying carrier relaxation, energy transfer, and phase transition mechanisms.

[0003] Existing commercial transient absorption spectroscopy systems mostly employ a single, fixed-wavelength pump source. Although wavelength tuning can be achieved by replacing the laser or using an optical parametric amplifier, the system structure is complex, costly, and the wavelength switching process is cumbersome, making it difficult to accurately compare excitation results from different pump wavelengths under the same experimental conditions. Current systems require recalibrating the optical path for wavelength switching, introducing errors and hindering accurate comparisons under identical conditions. Therefore, there is an urgent need in this field for an integrated transient absorption spectroscopy system that can conveniently switch pump wavelengths and achieve dual-wavelength excitation comparison measurements while maintaining optical path stability, to support in-depth research on photophysical mechanisms in complex material systems. Summary of the Invention

[0004] The purpose of this invention is to provide an integrated dual-wavelength pumped transient absorption spectroscopy acquisition system and method to overcome the shortcomings of existing technologies in achieving accurate dual-wavelength measurement of material ultrafast dynamics in a stable and interference-free environment.

[0005] The technical solution for achieving the objective of this invention is: a transient absorption spectral acquisition system and method integrating dual-wavelength pumping, comprising:

[0006] A femtosecond laser (1) is used to generate femtosecond laser pulses;

[0007] The first beam splitting system (2) is used to attenuate the energy of the femtosecond laser pulse;

[0008] The second beam splitting system (3) is used to split the attenuated laser pulse into a pump optical path and a probe optical path;

[0009] The detection optical path is provided with an optical path delay system (4), a supercontinuous white light generation system (5), a first filtering system (6) and a first converging system (7) in sequence. The optical path delay system is used to delay the detection light pulse in time. The supercontinuous white light generation system is used to convert the detection light into broadband supercontinuous white light. The first filtering system is used to filter out residual fundamental frequency light. The first converging system is used to focus the detection light onto the sample.

[0010] The pump optical path is provided with a chopping system (9), a wavelength conversion system (10), a second filtering system (11), and a second converging system (12) in sequence. The chopping system is used to frequency modulate the pump light. The wavelength conversion system converts the pump light wavelength to a second wavelength that is different from the output wavelength of the femtosecond laser, or keeps the output wavelength of the femtosecond laser, so as to realize the switching of dual-wavelength pumping conditions. The second filtering system is used to filter out residual fundamental frequency light. The second converging system is used to focus the pump light onto the sample and overlap it with the probe light in space at the sample.

[0011] The sample placement system (8) has a sample stage inside for placing samples and can be adjusted in all directions (front, back, left, right, up, down).

[0012] The third converging system (13), located at the probe light outlet of the sample placement system (8), is used to collect the probe light emitted from the sample;

[0013] Signal receiving system (14) is used to receive the probe light signal collected by the third converging system;

[0014] The signal acquisition system (15) is used to acquire and average the received signal to obtain transient absorption spectrum data;

[0015] The signal processing system (16) processes the obtained transient absorption spectrum data to obtain carrier dynamics information of the sample material.

[0016] Furthermore, the femtosecond laser (1) outputs a laser pulse width of 35 fs, a repetition frequency of 1 kHz, a center wavelength of 800 nm, and an output power of 3 W.

[0017] Furthermore, the first beam splitting system (2) is composed of two beam splitters arranged in sequence, and the second beam splitting system is composed of a half-wave plate and a polarizing beam splitting cube mirror.

[0018] Furthermore, the optical path delay system (4) includes a high-precision electric displacement stage and a corner mirror, with a time delay adjustment range of -0.3 ns to 3 ns, an accuracy of 2.5 µm, and a time accuracy better than 20 fs.

[0019] Furthermore, the white light spectrum generated by the supercontinuous white light generation system (5) covers the range of 450 nm to 1100 nm.

[0020] Furthermore, a supercontinuum white light generation system, including a pinhole aperture, an off-axis concave mirror, and a sapphire crystal, is used to convert the probe light into supercontinuum white light covering the 450 nm to 1100 nm wavelength range.

[0021] Furthermore, the sample placement system (8) includes a three-dimensional displacement stage and a sample clamp.

[0022] Furthermore, the wavelength conversion system (10) includes a BBO crystal for frequency doubling the pump light to 400 nm. By removing the frequency doubling crystal and correspondingly replacing the filter of the second filter system with an 800 nm bandpass filter, and at the same time replacing the reflector of the pump light path with a corresponding 800 nm high reflectivity lens, dual-wavelength pumping conditions of 800 nm and 400 nm are achieved.

[0023] A transient absorption spectroscopy acquisition method with integrated dual-wavelength pumping, implemented using the aforementioned transient absorption spectroscopy acquisition system with integrated dual-wavelength pumping, includes the following steps:

[0024] System setup and pre-calibration: The optical path is set up and pre-calibrated to ensure that the pump light and the probe light are spatially collinear and overlapped at the sample, and to ensure the stable generation of supercontinuum white light;

[0025] Sample loading: Fix the sample onto the sample stage of the sample placement system;

[0026] Environmental control: Monitoring and controlling the experimental environment;

[0027] Precise calibration of the optical path: After the environment stabilizes, the optical path is precisely calibrated to ensure that the pump light and the probe light are collinear and overlapped on the sample surface;

[0028] Data acquisition: The pump light is modulated using a chopper system, and the time delay is scanned using an optical path delay system. The reference signal (Ipump-off) when not excited by the pump light and the detection signal (Ipump-on) after being excited are acquired. The transient absorption spectrum data are obtained after multiple averaging.

[0029] Furthermore, it also includes: parameter scanning and inversion, changing at least one parameter among pump light wavelength and power, repeating the acquisition steps, obtaining dynamic data under different conditions, and inverting the carrier dynamic parameters of the sample.

[0030] Compared with the prior art, the significant advantages of this invention are: 1) It supports dual-wavelength pumping and wide-band detection, providing control over the excitation process and multi-dimensional detection capabilities; 2) The high-precision optical path delay system achieves femtosecond-level time resolution, which is suitable for ultrafast dynamics research; 3) The system has strong compatibility and can be applied to other two-dimensional materials or optoelectronic devices, providing a universal platform for materials research under extreme conditions. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the optical path structure of the system of the present invention;

[0032] Figure 2 This is a two-dimensional transient reflectance spectrum of molybdenum ditelluride in the example;

[0033] Figure 3 The figure shows the carrier dynamics curves of molybdenum telluride at different pump wavelengths in the example. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0035] Before describing the content of this invention, the following terms are defined as follows:

[0036] Reference Figure 1 The present invention integrates a dual-wavelength pumped transient absorption spectral acquisition system comprising the following components: a femtosecond laser 1, a first beam splitting system 2, a second beam splitting system 3, an optical path delay system 4, a supercontinuum white light generation system 5, a first filtering system 6, a first converging system 7, a sample placement system 8, a chopper system 9, a wavelength conversion system 10, a second filtering system 11, a second converging system 12, a third converging system 13, a signal receiving system 14, a signal acquisition system 15, and a signal processing system 16. Its optical path connections and functions are described below.

[0037] Femtosecond laser 1: Outputs femtosecond pulses with a center wavelength of 800 nm, a pulse width of 35 fs, a repetition frequency of 1 kHz, and an average power of 3 W.

[0038] First beam splitting system 2: Consists of two beam splitters arranged in sequence, used to attenuate the laser pulse energy to approximately 180mW.

[0039] The second beam splitting system 3 consists of a half-wave plate and a polarizing beam splitting cube mirror, which splits the attenuated beam into pump light and probe light with an energy ratio of 9:1.

[0040] Probe optical path: The probe light sequentially passes through the optical path delay system 4, the supercontinuum white light generation system 5, the first filter system 6, the first convergence system 7, and then is incident on the sample in the sample placement system 8. Wherein:

[0041] The optical path delay system 4 consists of a high-precision motorized displacement stage and corner mirrors, providing a continuously adjustable delay from -0.3 ns to 3 ns;

[0042] The supercontinuous white light generation system 5 includes a pinhole aperture, an off-axis concave mirror, and a sapphire crystal, which converts the probe light into 450-1100 nm supercontinuous white light.

[0043] The first filtering system 6 is used to filter out residual fundamental frequency light and noise;

[0044] The first converging system 7 focuses the probe light onto the sample.

[0045] Pump optical path: The pump light sequentially passes through chopper system 9, wavelength conversion system 10, second filter system 11, and second convergence system 12 before spatially overlapping with the probe light at the sample location. Wherein:

[0046] The chopper system 9 modulates the pump light at a frequency of 500 Hz;

[0047] The wavelength conversion system 10 is an optional module that can be inserted with a BBO crystal to double the frequency of the 800 nm pump light to 400 nm, or not inserted with a crystal to maintain 800 nm.

[0048] The second filtering system 11 is used to filter out residual fundamental frequency light;

[0049] The second converging system 12 focuses the pump light onto the sample.

[0050] The third converging system 13 is located behind the sample and collects the emitted probe light and guides it into the signal receiving system 14.

[0051] Signal receiving system 14: Spectrometer, which converts optical signals into electrical signals.

[0052] Signal acquisition system 15: Acquires and averages electrical signals to obtain transient absorption spectrum data.

[0053] Signal processing system 16: processes the data and extracts carrier dynamics information.

[0054] Furthermore, the wavelength conversion system 10 is an optional configuration: when using 400 nm pump light, a BBO crystal is inserted, and the second filtering system 11 uses a 400 nm bandpass filter; when using 800 nm pump light, the BBO crystal is removed, and the second filtering system 11 is replaced with an 800 nm bandpass filter, while the reflector in the pump light path is replaced with an 800 nm high-reflectivity lens. This simple replacement allows for switching between 800 nm and 400 nm dual-wavelength pumping conditions, and the optical path geometry remains unchanged after switching, requiring no recalibration.

[0055] Based on the above system, the present invention also provides a transient absorption spectral acquisition method integrating dual-wavelength pumping, comprising the following steps:

[0056] System setup and pre-calibration: Set up the optical path and pre-adjust to ensure that the pump light and probe light are spatially collinear and overlapped at the sample, and ensure the stable generation of supercontinuous white light.

[0057] Sample loading: Fix the sample to be tested onto the sample stage of the sample placement system 8.

[0058] Environmental control: Monitor the experimental environment (temperature, humidity, vibration, etc.) to ensure that it remains stable during the measurement process.

[0059] Precise optical path calibration: After the environment stabilizes, finely adjust each convergence system to ensure optimal spatial overlap between the pump light and the probe light on the sample surface and optimize signal collection efficiency.

[0060] Data acquisition: The chopper system 9 is activated to modulate the pump light. The optical path delay system 4 scans the time delay and acquires the reference signal when the pump light is off and the detection signal when the pump light is on. After multiple averaging, transient absorption spectrum data is obtained.

[0061] Parameter scanning and inversion: Change parameters such as pump light wavelength and power, repeat step 5, obtain dynamic data under different conditions, and invert the carrier dynamic parameters of the sample by methods such as global fitting.

[0062] In the text, the term "femtosecond" refers to a unit of measurement for the length of time. One femtosecond is equal to one quadrillionth of a second, or 1e-15 seconds.

[0063] The term "β-phase barium borate crystal" refers to a nonlinear optical crystal whose function is to convert incident fundamental frequency laser light into second harmonic light with a frequency exactly twice that of the fundamental frequency (i.e., half the wavelength) through a second-order nonlinear optical effect. It is abbreviated as BBO crystal.

[0064] The term "pulse width" refers to the duration of a laser pulse, that is, the length of time from the start to the end of the pulse, or simply pulse width.

[0065] Example

[0066] To verify the effectiveness of the present invention, the following experiment was conducted.

[0067] Reference Figure 1 This embodiment integrates a dual-wavelength pumped transient absorption spectrum acquisition system, including a femtosecond laser 1, a first beam splitting system 2, a second beam splitting system 3, an optical path delay system 4, a supercontinuous white light generation system 5, a first filtering system 6, a first converging system 7, a sample placement system 8, a chopper system 9, a wavelength conversion system 10, a second filtering system 11, a second converging system 12, a third converging system 13, a signal receiving system 14, a signal acquisition system 15, and a data processing system 16.

[0068] The femtosecond laser 1 outputs a high-energy femtosecond pulse, which is first incident on the first beam splitting system 2. In this embodiment, the system consists of two beam splitters arranged in sequence, with reflection / transmission ratios of 70:30 and 80:20, respectively. The laser pulse energy is attenuated to about 180 mW through two beam splits.

[0069] The attenuated laser pulse enters the second beam-splitting system 3, which consists of a half-wave plate and a polarizing beam-splitting cube mirror. By adjusting the angle of the half-wave plate, the beam is split into beams with an energy ratio of 9:1, thus forming a pump beam path with higher energy and a probe beam path with lower energy.

[0070] The weaker probe light is guided by a reflector into the optical path delay system 4. This system consists of a high-precision motorized stage and corner reflectors fixed on it. The stage has a displacement accuracy of 2.5 µm, equivalent to a time accuracy of 16.7 fs, and can provide a continuously adjustable time delay from -0.3 ns to 3 ns.

[0071] The delayed probe pulse enters the supercontinuum white light generation system 5. Specifically, the probe light is first narrowed by a 2 mm aperture diaphragm, and then focused onto a 3 mm thick sapphire crystal by an off-axis parabolic mirror with a focal length of 50 mm. Based on the nonlinear effect of the crystal, supercontinuum white light with a spectral range covering 450 nm to 1100 nm is generated. The generated supercontinuum white light is then collimated and expanded by an off-axis parabolic mirror with a focal length of 100 mm.

[0072] The expanded supercontinuous white light passes through the first filtering system 6. In this embodiment, an 800 nm notch filter is used to filter out the residual 800 nm fundamental frequency light and other nonlinear noise during the white light generation process, thus obtaining a pure broadband probe light. The filtered probe light is focused by the first converging system 7 (in this embodiment, a convex lens with a focal length of 100 mm) and passes through the sample placement system 8, finally converging on the sample surface.

[0073] On the other hand, the pump light obtained by the second beam splitting system 3 is guided by a mirror through the chopper system 9. The chopper is provided with an external trigger signal by the femtosecond laser 1, which periodically modulates the pump light at a frequency of 500 Hz to provide a reference for subsequent differential signal detection.

[0074] The modulated pump light enters the pump wavelength frequency doubling system 10. In this embodiment, a β-phase barium borate (BBO) crystal is used to frequency double the center wavelength of the pump light from 800 nm to 400 nm. The frequency-doubled beam passes through the second filtering system 11. In this embodiment, a bandpass filter with a center wavelength of 400 nm is used to strictly filter out residual 800 nm fundamental frequency light, ensuring the purity of the pump light acting on the sample. The purified 400 nm pump light is focused by the second converging system 12 (in this embodiment, a convex lens with a focal length of 300 mm) and passes through the optical window of the sample chamber, precisely achieving spatial collinear overlap with the probe light on the sample surface.

[0075] The probe light signal reflected from the sample surface is collected and focused by the third focusing system 13 (in this embodiment, a convex lens with a focal length of 50 mm) to the fiber optic probe inlet of the signal receiving system 14. In this embodiment, the signal receiving system 14 is a spectrometer with a wavelength response range covering 200 nm to 1100 nm. The signal acquisition system 15 is connected to a computer for recording and processing spectral data.

[0076] Measurement methods and operating procedures

[0077] Based on the above system, the specific steps for transient absorption spectroscopy measurement of molybdenum ditelluride samples are as follows:

[0078] Optical path pre-calibration and sample loading: The optical path was constructed and pre-calibrated in a clean room. By adjusting each optical path component, the pump light and probe light were made to achieve spatial collinear overlap at the preset sample placement position, and the spectral and spatial modes of the supercontinuum white light were kept stable. Subsequently, the molybdenum ditelluride sample was reliably fixed on the sample stage inside the sample placement system 8.

[0079] Precise optical path calibration and time zero-point search: After the optical path stabilizes, a fine recalibration is performed. The first converging system 7, the second converging system 12, and the third converging system 13 are finely adjusted to ensure optimal spatial overlap between the pump light and the probe light at the same point on the sample surface, and to ensure that the reflected probe light signal is completely collected by the third converging system 13. Subsequently, the intensity of the probe light signal is monitored by the signal acquisition system 15, and the motorized stage of the optical path delay system 4 is controlled to scan and find the point of abrupt change in the intensity of the pump light and probe light signals at zero time, i.e., the time zero point.

[0080] Transient absorption signal acquisition: After finding the zero point in time, the data acquisition program is officially started. The signal acquisition system 15 (controlled by a LabVIEW program) synchronously controls the chopper 9, the optical path delay system 4, and the signal receiving system 14. At each set delay time point, the system automatically acquires and records the reference signal (Ipump-off) before being excited by the pump light and the probe signal (Ipump-on) after being excited by the pump light. The reference signal (Ipump-off) before being excited by the pump light is subtracted from the probe signal (Ipump-on) after being excited by the pump light. Multiple measurements (20 times) are performed for each data point, and the average value is taken to effectively suppress noise. By scanning the entire delay time range, a two-dimensional dataset of transient absorption spectra changing with time delay is finally obtained.

[0081] Data Analysis and Kinetic Inversion: The raw data after acquisition and averaging are processed. First, spectral chirp processing is performed. Then, algorithms such as global fitting and single-wavelength kinetic fitting are used to extract the time constants of different relaxation processes from the transient spectral data, thereby obtaining the ultrafast carrier dynamics information of molybdenum ditelluride at different pump wavelengths.

[0082] Multi-parameter condition detection: To further study material properties, the above steps can be repeated by changing experimental conditions. For example, the pump light energy can be changed to study the excitation density dependence, and the pump light wavelength can be adjusted to explore the modulation of the transient absorption spectrum of the sample by the pump light, thereby comprehensively improving the understanding of the internal dynamic processes of molybdenum ditelluride materials.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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 this specification.

[0084] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A transient absorption spectral acquisition system and method integrating dual-wavelength pumping, characterized in that, include: A femtosecond laser (1) is used to generate femtosecond laser pulses; The first beam splitting system (2) is used to attenuate the energy of the femtosecond laser pulse; The second beam splitting system (3) is used to split the attenuated laser pulse into a pump optical path and a probe optical path; The detection optical path is provided with an optical path delay system (4), a supercontinuous white light generation system (5), a first filtering system (6) and a first converging system (7) in sequence. The optical path delay system is used to delay the detection light pulse in time. The supercontinuous white light generation system is used to convert the detection light into broadband supercontinuous white light. The first filtering system is used to filter out residual fundamental frequency light. The first converging system is used to focus the detection light onto the sample. The pump optical path is provided with a chopping system (9), a wavelength conversion system (10), a second filtering system (11), and a second converging system (12) in sequence. The chopping system is used to frequency modulate the pump light. The wavelength conversion system converts the pump light wavelength to a second wavelength that is different from the output wavelength of the femtosecond laser, or keeps the output wavelength of the femtosecond laser, so as to realize the switching of dual-wavelength pumping conditions. The second filtering system is used to filter out residual fundamental frequency light. The second converging system is used to focus the pump light onto the sample and overlap it with the probe light in space at the sample. The sample placement system (8) has a sample stage inside for placing samples and can be adjusted in all directions (front, back, left, right, up, down). The third converging system (13), located at the probe light outlet of the sample placement system (8), is used to collect the probe light emitted from the sample; Signal receiving system (14) is used to receive the probe light signal collected by the third converging system; The signal acquisition system (15) is used to acquire and average the received signal to obtain transient absorption spectrum data; The signal processing system (16) processes the obtained transient absorption spectrum data to obtain carrier dynamics information of the sample material.

2. The transient absorption spectral acquisition system with integrated dual-wavelength pumping according to claim 1, characterized in that, The femtosecond laser (1) outputs a laser pulse width of 35 fs, a repetition frequency of 1 kHz, a center wavelength of 800 nm, and an output power of 3 W.

3. The integrated dual-wavelength pumped transient absorption spectral acquisition system according to claim 1, characterized in that, The first beam splitting system (2) is composed of two beam splitting mirrors arranged in sequence, and the second beam splitting system is composed of a half-wave plate and a polarizing beam splitting cube mirror.

4. The integrated dual-wavelength pumped transient absorption spectral acquisition system according to claim 1, characterized in that, The optical path delay system (4) includes a high-precision electric displacement stage and a corner mirror, with a time delay adjustment range of -0.3 ns to 3 ns, an accuracy of 2.5 µm, and a time accuracy better than 20 fs.

5. The transient absorption spectral acquisition system with integrated dual-wavelength pumping according to claim 1, characterized in that, The supercontinuous white light generation system (5) generates white light with a spectral range covering 450 nm to 1100 nm.

6. The transient absorption spectral acquisition system with integrated dual-wavelength pumping according to claim 5, characterized in that, A supercontinuum white light generation system, comprising a pinhole aperture, an off-axis concave mirror, and a sapphire crystal, is used to convert probe light into supercontinuum white light covering the 450 nm to 1100 nm wavelength range.

7. The transient absorption spectral acquisition system with integrated dual-wavelength pumping according to claim 1, characterized in that, The sample placement system (8) includes a three-dimensional displacement stage and a sample clamp.

8. The transient absorption spectral acquisition system with integrated dual-wavelength pumping according to claim 1, characterized in that, The wavelength conversion system (10) includes a BBO crystal for frequency doubling the pump light to 400 nm. By removing the frequency doubling crystal and replacing the filter of the second filter system with an 800 nm bandpass filter, and replacing the reflector of the pump light path with a corresponding 800 nm high reflectivity lens, dual-wavelength pumping conditions of 800 nm and 400 nm are achieved.

9. A transient absorption spectral acquisition method integrating dual-wavelength pumping, characterized in that, The transient absorption spectral acquisition system with integrated dual-wavelength pumping as described in any one of claims 1-8 is used to achieve this, comprising the following steps: System setup and pre-calibration: The optical path is set up and pre-calibrated to ensure that the pump light and the probe light are spatially collinear and overlapped at the sample, and to ensure the stable generation of supercontinuum white light; Sample loading: Fix the sample onto the sample stage of the sample placement system; Environmental control: Monitoring and controlling the experimental environment; Precise calibration of the optical path: After the environment stabilizes, the optical path is precisely calibrated to ensure that the pump light and the probe light are collinear and overlapped on the sample surface; Data acquisition: The pump light is modulated using a chopper system, and the time delay is scanned using an optical path delay system. The reference signal (Ipump-off) when not excited by the pump light and the detection signal (Ipump-on) after being excited are acquired. The transient absorption spectrum data are obtained after multiple averaging.

10. The transient absorption spectral acquisition method with integrated dual-wavelength pumping according to claim 1, further comprising: Parameter scanning and inversion involves changing at least one parameter, such as pump light wavelength and power, repeating the acquisition steps, obtaining dynamic data under different conditions, and inverting the carrier dynamic parameters of the sample.

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