A nanosecond transient absorption spectroscopy test system and its test method

Abstract

The present invention relates to the technical field of spectral testing, and provides a nanosecond transient absorption spectroscopy testing system and a testing method thereof. The testing system includes: an excitation light source module, an electro-excitation module, a probe light source module, an optical path module, and a system control module; the excitation light source module includes an excitation light source and an optical parametric amplifier; the excitation light source emits excitation light, which is emitted to the optical path module through the optical parametric amplifier; the electro-excitation module includes a function signal generator; the probe light source module includes a white light laser; the white light laser emits white light; the optical path module includes: a first optical path, a filter, a beam splitter, a second optical path, a third optical path, a fourth optical path, and a sample displacement stage; the system control module includes an industrial personal computer, a timing card, a delay calculator, a detection spectrometer, a probe light detector, a reference monochromator, and a reference detector. The present invention can realize nanosecond transient absorption spectroscopy testing based on the pump-probe method.

Description

Technical Field

[0001] The present invention relates to the technical field of spectral testing, and particularly to a nanosecond transient absorption spectroscopy testing system and a testing method thereof. Background Art

[0002] Transient absorption spectroscopy technology is one of the important scientific research means for discovering and exploring the photoinduced phenomena of materials and their time evolution processes and mechanisms. With the rapid development of basic scientific research in China, this technology is more widely used in related research such as solar cell materials, semiconductor materials, and photocatalytic materials.

[0003] According to the time range and time accuracy detected by the instrument, it can be subdivided into: ultrafast transient absorption spectroscopy (time detection range: femtoseconds - several nanoseconds, time accuracy: femtoseconds) and nanosecond transient absorption spectroscopy (time detection range: nanoseconds - seconds, time accuracy: more than ten nanoseconds). The common instrument for nanosecond transient absorption spectroscopy is the flash photolysis spectroscopy system. It uses relatively high pump energy and detection power, and there are the following disadvantages in the testing process:

[0004] (1) It is easily interfered by scattered fluorescence and phosphorescence;

[0005] (2) The high-power detection light will change the kinetic behavior, resulting in a positive deviation in the lifetime value. At the same time, the high-power detection light can easily "completely burn out" the sample;

[0006] (3) The signal-to-noise ratio of the data is slightly poor;

[0007] (4) The pump energy is single, and it can only photo-excite the sample. Summary of the Invention

[0008] The present invention mainly solves the technical problems in the prior art that the high-power detection light in nanosecond transient absorption spectroscopy detection will change the kinetic behavior, result in a positive deviation in the lifetime value, at the same time, the high-power detection light can easily "completely burn out" the sample, the signal-to-noise ratio of the data is slightly poor, and the pump energy is single. A nanosecond transient absorption spectroscopy testing system and a testing method thereof are proposed to realize a transient absorption measurement system with nanosecond resolution, improve the detection time accuracy and signal-to-noise ratio, and improve the accuracy and reliability of transient absorption data measurement of materials.

[0009] The present invention provides a nanosecond transient absorption spectroscopy testing system, including: an excitation light source module, an electro-excitation module, a detection light source module, an optical path module, and a system control module;

[0010] The excitation light source module includes: an excitation light source and an optical parametric amplifier; the excitation light source emits excitation light, which is emitted to the optical path module through the optical parametric amplifier;

[0011] The electro-excitation module includes: a function signal generator; the function signal generator has two channels, and the electrical pulse signal of the first channel of the function signal generator is applied to the positive and negative electrodes of the sample for pump electro-excitation; the electrical pulse signal of the second channel of the function signal generator is output to the timing card;

[0012] The detection light source module includes: a white light laser; the white light laser emits white light;

[0013] The optical path module includes: a first optical path, a filter, a beam splitter, a second optical path, a third optical path, a fourth optical path, and a sample displacement stage;

[0014] The first optical path projects the excitation light onto the sample; among them, the sample is placed on the sample displacement stage;

[0015] The filter filters the white light, and the beam splitter splits the filtered white light; after splitting, 20% of the white light is reflected as reference light and enters the system control module through the second optical path; the other 80% of the white light is used as detection light, which is focused on the sample through the third optical path, and then becomes parallel light through the fourth optical path and enters the system control module;

[0016] The system control module includes: an industrial control computer, a timing card, a delay calculator, a detection spectrometer, a detection light detector, a reference spectrometer, and a reference detector;

[0017] The detection spectrometer is signal-connected to the detection light detector, and the reference spectrometer is signal-connected to the reference detector; the timing card, the delay calculator, the detection light detector, the reference detector, and the white light laser are respectively signal-connected to the industrial control computer;

[0018] The reference light enters the reference monochromator and is projected onto the reference detector; the detection light enters the detection spectrometer and is projected onto the detection light detector.

[0019] Preferably, the timing card is respectively signal-connected to the detection light detector, the reference detector, the excitation light source, the function signal generator, the white light laser, and the delay calculator.

[0020] Preferably, the excitation light source adopts a femtosecond laser or a semiconductor laser;

[0021] The repetition frequency of the femtosecond laser or the semiconductor laser is 1KHz, and the wavelength range is 200nm - 2000nm.

[0022] Preferably, the repetition frequency of the white light laser is 2KHz, the pulse width is less than 1ns, and the spectral range is 350nm - 2000nm.

[0023] Preferably, the first optical path includes: a first mirror, a first small hole, a first attenuation sheet, a first plano-convex lens, and a second mirror, which are arranged in sequence.

[0024] Preferably, the second optical path includes: a third mirror, a second attenuation sheet, a second plano-convex lens, and a first fiber optic receiver, which are arranged in sequence.

[0025] Preferably, the third optical path includes: a fourth mirror, a second small hole, a third attenuation sheet, and a parabolic mirror, which are arranged in sequence.

[0026] Preferably, the fourth optical path includes: a third plano-convex lens, a detachable mirror, a third small hole, a fourth plano-convex lens, and a second fiber optic receiver, which are arranged in sequence;

[0027] The fourth optical path further includes: a fifth mirror, a fifth plano-convex lens, and a sixth mirror, which are arranged in sequence;

[0028] The outgoing direction of the sixth mirror corresponds to that of the detachable mirror.

[0029] Correspondingly, the present invention also provides a testing method for a nanosecond transient absorption spectroscopy testing system according to any embodiment of the present invention, including the following processes:

[0030] Step 1: The excitation light source 1 or the 1KHz clock signal output by the function signal generator is input to the timing card. The timing card generates a first reference signal and a second reference signal according to the clock signal, and then generates a D trigger signal and a P trigger signal according to the first reference signal, and generates a detector trigger signal according to the second reference signal;

[0031] Step 2: The timing card inputs the D trigger signal and the P trigger signal to the white light laser; and outputs the detector trigger signal to the probe light detector and the reference detector at the same time;

[0032] Step 3: According to the timing control of the timing card, the system is tested: The excitation light source emits excitation light, which is emitted to the optical path module through the optical parametric amplifier, and the excitation light is projected onto the sample through the first optical path for pump-induced excitation; or the electrical pulse signal of the first channel of the function signal generator is applied to the positive and negative electrodes of the sample for pump electro-induced excitation;

[0033] The filter filters the white light, and the beam splitter splits the filtered white light; after splitting, 20% of the white light is reflected as the reference light and enters the system control module through the second optical path; the other 80% of the white light is used as the probe light, which is focused onto the sample through the third optical path, and then becomes parallel light and enters the system control module through the fourth optical path; the reference light enters the reference monochromator and is projected onto the reference detector; the probe light enters the probe spectrometer and is projected onto the probe light detector;

[0034] Step 4: According to the data obtained by the probe light detector and the reference detector, calculate the TA signal value according to the following formula:

[0035]

[0036] In the formula, TA(ΔT / T) represents the transient absorption transmittance value, I 1-pump represents the measured value of the probe detector in the excited state, IRef 1-pump represents the measured value of the reference detector in the excited state, I 1-unpump represents the measured value of the probe detector in the unexcited state, IRef 1-unpump represents the measured value of the reference detector in the unexcited state;

[0037] Step 5: Calculate the time delay t value corresponding to each TA signal value to obtain the test result of the nanosecond transient absorption spectrum.

[0038] Preferably, the repetition frequency of the first reference signal is 1 KHz and has a delay time t1, the delay time t1 is adjustable, and the adjustment range of the delay time t1 is 0 - 500 us;

[0039] The repetition frequency of the D trigger signal is 2 KHz, the delay time is 0 us, and the high-level duty cycle is 50%;

[0040] The repetition frequency of the P trigger signal is 2 KHz, the delay time is t3, and the high-level duty cycle is adjustable;

[0041] The repetition frequency of the second reference signal is 2 KHz, and the delay time is t2;

[0042] The repetition frequency of the detector trigger signal is 2 KHz, and the delay time is 0 us.

[0043] A nanosecond transient absorption spectrum test system and its test method provided by the present invention use a femtosecond light source as the excitation light, a nanosecond white light laser source as the probe light, a timing card to control the synchronous operation of corresponding components, and a high-speed detector to detect the light intensity data, realizing a transient absorption measurement system with nanosecond resolution, improving the detection time accuracy and signal-to-noise ratio, and thus improving the accuracy and reliability of measuring the transient absorption data of materials. An electro-excitation module is set up to enable two tests of pump light-induced excitation and pump electro-excitation, and the applicable scenarios are more extensive. Description of the Drawings

[0044] Figure 1 is the layout schematic diagram of the nanosecond transient absorption spectrum test system provided by the present invention.

[0045] Figure 2 is the connection schematic diagram of the timing card provided by the present invention;

[0046] Figure 3 It is a schematic diagram of the timing control of the timing card provided by the present invention;

[0047] Figure 4 It is a schematic diagram of the relationship between the white light pulse and the excitation light pulse of the present invention;

[0048] Figure 5 It is a schematic diagram of the data acquisition status of the detection light detector and the reference detector of the present invention;

[0049] Figure 6 It is a schematic diagram of the timing card delay jitter of the present invention;

[0050] Figure 7 It is a schematic diagram of the actual time delay data of the detected white light pulse and the excitation light pulse;

[0051] Figure 8 It is a schematic diagram of the relationship between the scanning Step and the data distribution Step of the present invention;

[0052] Figure 9 It is a schematic diagram of the transient absorption 3D data of the present invention;

[0053] Figure 10 It is a schematic diagram of the transient absorption spectrum data of the present invention;

[0054] Figure 11 It is a schematic diagram of the transient absorption kinetic data of the present invention.

[0055] Reference numerals: 1. Excitation light source; 2. Optical parametric amplifier; 3. First mirror; 4. First small hole; 5. First attenuation sheet; 6. First plano-convex lens; 7. Second mirror; 8. White light laser; 9. Filter; 10. Beam splitter; 11. Third mirror; 12. Second attenuation sheet; 13. Second plano-convex lens; 14. First fiber optic receiver; 15. Reference monochromator; 16. Reference detector; 17. Fourth mirror; 18. Second small hole; 19. Third attenuation sheet; 20. Parabolic mirror; 21. Sample displacement stage; 22. Third plano-convex lens; 23. Removable mirror; 24. Third small hole; 25. Fourth plano-convex lens; 26. Second fiber optic receiver; 27. Detection spectrometer; 28. Fifth mirror; 29. Detection light detector; 30. Delay calculator; 31. Timing card; 32. Industrial control computer; 33. Function signal generator; 34. Fifth plano-convex lens; 35. Sixth mirror. Detailed implementation manners

[0056] To make the technical problems solved by the present invention, the technical solutions adopted, and the achieved technical effects clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only the parts related to the present invention are shown in the drawings, rather than all the content.

[0057] As Figure 1 shown, the nanosecond transient absorption spectroscopy test system provided by the embodiment of the present invention includes: an excitation light source module I, an electro-excitation module II, a detection light source module III, an optical path module IV, and a system control module V.

[0058] The excitation light source module I includes: an excitation light source 1 and an optical parametric amplifier 2; the excitation light source 1 emits excitation light and emits it into the optical path module IV through the optical parametric amplifier 2; the excitation light source 1 uses a femtosecond laser or a semiconductor laser, and the emitted pulsed laser is used as the system pump excitation light; the repetition frequency of the femtosecond laser or the semiconductor laser is 1KHz, and the wavelength range is 200nm - 2000nm.

[0059] The electro-excitation module II includes: a function signal generator 33; the function signal generator 33 has two channels, and the two channels synchronously output pulsed signals of 1KHz; the electrical pulsed signal of the first channel of the function signal generator 33 is applied to the positive and negative electrodes of the sample for pump electro-excitation; the electrical pulsed signal of the second channel of the function signal generator 33 is output to the timing card 31 to facilitate the timing card 31 to perform system timing control so that the detection light source module III synchronously outputs detection light.

[0060] The excitation light source module I realizes the photo-excitation mode, and the electro-excitation module II realizes the electro-excitation mode.

[0061] The detection light source module III includes: a white light laser 8; the white light laser 8 emits white light; the white light laser 8 is used as the detection light source, the repetition frequency of the white light laser 8 is 2KHz, the pulse width is less than 1ns, realizing the 1ns time resolution of the system, and the spectral range is 350nm - 2000nm.

[0062] The optical path module IV includes: a first optical path, a filter 9, a beam splitter 10, a second optical path, a third optical path, a fourth optical path, and a sample displacement stage 21.

[0063] The first optical path projects the excitation light onto the sample; the sample is placed on the sample displacement stage 21; the filter 9 filters the white light emitted by the white light laser 8 to eliminate the strong 1064 nm light in the white light, and the beam splitter 10 splits the filtered white light; after splitting, 20% of the white light is reflected as the reference light and enters the system control module V through the second optical path; the other 80% of the white light is used as the detection light, which is focused onto the sample through the third optical path, and then becomes parallel light through the fourth optical path and enters the system control module V.

[0064] The first optical path includes: a first reflector 3, a first small hole 4, a first attenuation sheet 5, a first plano-convex lens 6, and a second reflector 7 arranged in sequence. The excitation light source 1 emits excitation light, which passes through the first reflector 3, the first small hole 4, the first attenuation sheet 5, the first plano-convex lens 6, and the second reflector 7 and finally hits the sample, overlapping with the white light. The sample displacement stage 21 can perform scanning motion according to the set trajectory to prevent the detection light or the excitation light from hitting one position of the sample for a long time and damaging the sample.

[0065] The second optical path includes: a third reflector 11, a second attenuation sheet 12, a second plano-convex lens 13, and a first optical fiber receiver 14 arranged in sequence. 20% of the white light is reflected as the reference light of the system, which passes through the third reflector 11, the second attenuation sheet 12, the second plano-convex lens 13, and the first optical fiber receiver 14 and enters the reference monochromator 15 and then hits the reference detector 16.

[0066] The third optical path includes: a fourth reflector 17, a second small hole 18, a third attenuation sheet 19, and a parabolic mirror 20 arranged in sequence. The other 80% of the white light is transmitted through the fourth reflector 17, the second small hole 18, the third attenuation sheet 19, and the parabolic mirror 20 and focused onto the sample.

[0067] The fourth optical path includes: a third plano-convex lens 22, a detachable reflector 23, a third small hole 24, a fourth plano-convex lens 25, and a second optical fiber receiver 26 arranged in sequence. The fourth optical path also includes: a fifth reflector 28, a fifth plano-convex lens 34, and a sixth reflector 35 arranged in sequence; the outgoing direction of the sixth reflector 35 corresponds to that of the detachable reflector 23. After passing through the sample, the detection light passes through the third plano-convex lens 22, and the divergent white light becomes parallel light, which is focused through the third small hole 24 and enters the second optical fiber receiver 26, and then enters the detection spectrometer 27 for spectral splitting and hits the detection light detector 29. This path is the transmission mode, and the detachable reflector 23 needs to be removed. The present invention can also achieve the reflection mode. The detachable reflector 23 needs to be installed. After passing through the sample, the detection light passes through the fifth reflector 28, the fifth plano-convex lens 34, the sixth reflector 35, the detachable reflector 23 in sequence, and then is focused through the third small hole 24 and enters the second optical fiber receiver 26.

[0068] The system control module V includes: an industrial control computer 32, a timing card 31, a delay calculator 30, a detection spectrometer 27, a detection optical detector 29, a reference spectrometer 15, and a reference detector 16. The detection spectrometer 27 is signal-connected to the detection optical detector 29, and the reference spectrometer 15 is signal-connected to the reference detector 16; the timing card 31, the delay calculator 30, the detection optical detector 29, the reference detector 16, and the white light laser 8 are respectively signal-connected to the industrial control computer 32; the timing card 31 is respectively signal-connected to the detection optical detector 29, the reference detector 16, the excitation light source 1, the function signal generator 33, the white light laser 8, and the delay calculator 30.

[0069] The reference light enters the reference monochromator 15 and is incident on the reference detector 16; the detection light enters the detection spectrometer 27 and is incident on the detection optical detector 29.

[0070] The industrial control computer 32 realizes the control of the timing card 31 and other related hardware, and its hardware wiring method is as Figure 2 shown. The PFI32 terminal of the timing card 31 is respectively connected to the Trigger In terminal of the detection optical detector 29, the Trigger In terminal of the reference detector 16, and the InputA terminal of the delay calculator 30. The PFI35 terminal of the timing card 31 is respectively connected to the Trigger Out terminal of the excitation light source 1 and the Trigger Out terminal of the function signal generator 33. The PFI37 terminal of the timing card 31 is respectively connected to the DFB terminal of the white light laser 8. The PFI38 terminal of the timing card 31 is respectively connected to the PUMP terminal of the white light laser 8. The PFI39 terminal of the timing card 31 is respectively connected to the Arm InputE terminal of the delay calculator 30. The InputB terminal of the delay calculator 30 is connected to the Trigger Out terminal of the white light laser 8.

[0071] The timing card 31 can generate synchronous trigger signals according to the clock signals output by the excitation light source 1 or the function signal generator 33, control the white light laser 8 to synchronously output pulses, and control the detection detector 29, the reference detector 16, and the reference detector 16 and the delay calculator 30 to synchronously collect data. Its timing control diagram is as Figure 3 shown.

[0072] The test and detection method of the nanosecond transient absorption spectroscopy test system of the present invention includes the following processes:

[0073] Step 1: The 1KHz clock signal output by the excitation light source 1 or the function signal generator 33 is input to the timing card 31. The timing card 31 generates a first reference signal (REF1 signal) and a second reference signal (REF2 signal) according to the clock signal, and then generates a D trigger signal (DFB signal) and a P trigger signal (PUMP signal) according to the first reference signal (REF1 signal), and generates a detector trigger signal (CMOS signal) according to the second reference signal (REF2 signal).

[0074] Among them, the first reference signal (REF1 signal) has a repetition frequency of 1KHz and has a delay time t1. The delay time t1 is adjustable, and the adjustment range of the delay time t1 is 0 - 500us.

[0075] The D trigger signal (DFB signal) has a repetition frequency of 2KHz, a delay time of 0us, and a high-level duty cycle of 50%.

[0076] The P trigger signal (PUMP signal) has a repetition frequency of 2KHz, a delay time of t3, and an adjustable high-level duty cycle.

[0077] The second reference signal (REF2 signal) has a repetition frequency of 2KHz and a delay time of t2.

[0078] The detector trigger signal (CMOS signal) has a repetition frequency of 2KHz and a delay time of 0us.

[0079] Step 2: The timing card 31 inputs the D trigger signal (DFB signal) and the P trigger signal (PUMP signal) to the white light laser 8; and outputs the detector trigger signal (CMOS signal) to the detection light detector 29 and the reference detector 16 at the same time.

[0080] Specifically, the DFB signal and the PUMP signal are respectively input to the DFB interface and the PUMP interface of the white light laser 8, so that the white light laser 8 emits light, and the relationship between the white light pulse and the excitation light pulse (or the electro-excitation pulse signal) is as Figure 4 , realizing the pump-probe relationship, and the time delay t1' between the excitation light and the white light is continuously adjustable from -10ns to 450us with the adjustment of the delay time t1 of the REF1 signal.

[0081] The CMOS signal is output to the detection light detector 29 and the reference detector 16 at the same time, realizing synchronous detection of the detection light and the white light pulse acquisition by the detection light detector 29 and the reference detector 16. The white light time of the detection light detector 29 is set to 460us, and the exposure time is greater than the white light delay range, ensuring that the detection window of the system is 450us.

[0082] The REF2 signal serves as the frame Start signal for the detection light detector 29 and the reference detector 16, and the CMOS signal serves as the acquisition signal for the detection light detector 29 and the reference detector 16, enabling data acquisition to always start in the PUMP state, as Figure 5 shown.

[0083] Step 3: According to the timing control of the timing card 31, conduct system testing: The excitation light source 1 emits excitation light, which is emitted into the optical path module IV through the optical parametric amplifier 2, and the excitation light is directed onto the sample through the first optical path for pump light-induced excitation; or the electrical pulse signal of the first channel of the function signal generator 33 is applied to the positive and negative electrodes of the sample for pump electro-induced excitation;

[0084] The filter 9 filters the white light, and the beam splitter 10 splits the filtered white light; after splitting, 20% of the white light is reflected as the reference light and enters the system control module V through the second optical path; the other 80% of the white light is used as the detection light, which is focused onto the sample through the third optical path, and then becomes parallel light through the fourth optical path and enters the system control module V; the reference light enters the reference monochromator 15 and is directed onto the reference detector 16; the detection light enters the detection spectrometer 27 and is directed onto the detection light detector 29;

[0085] Step 4: According to the data obtained from the detection light detector 29 and the reference detector 16, calculate the TA signal value according to the following formula:

[0086]

[0087] In the formula, TA(ΔT / T) represents the transient absorption transmittance value, I 1-pump represents the measurement value of the detection detector in the excited state, IRef 1-pump represents the measurement value of the reference detector in the excited state, I 1-unpump represents the measurement value of the detection detector in the unexcited state, IRef 1-unpump represents the measurement value of the reference detector in the unexcited state;

[0088] The obtained TA signal value can effectively eliminate the white light jitter of the white light laser and improve the white light signal-to-noise ratio.

[0089] Step 5: Calculate the time delay t value corresponding to each TA signal value to obtain the test result of the nanosecond transient absorption spectrum.

[0090] The time resolution of the system is actually the time delay accuracy between the excitation light and the detection light. Earlier systems relied more on the accuracy of the timing card 31. The timing card of the present invention can use NIPCIE-6612 with an internal clock of 100 MHz, and the time resolution of its counter output is 10 ns. That is, for an output signal generated according to an input signal, there will be a 10-ns jitter in time, as Figure 6 shown. To improve the time resolution of the system, the system is configured with a delay calculator 30, and the delay calculator 30 can use CNT91.

[0091] While the system controls the detection light detector 29 and the reference detector 16 to collect data, the timing card 31 generates an electrical pulse signal with a 0-us delay according to the REF2 signal. The signal is connected to the InputE interface of the delay calculator 30. At the same time, the Trigger Out signals of the excitation light source 1 and the function signal generator 33 are connected to the CHA interface of the delay calculator 30, and the Trigger Out signal of the white light laser 8 is connected to the CHB interface of the delay calculator 30. After receiving the InputE signal, the delay counter 30 synchronizes with the detection light detector 29 and the reference detector 16 to collect and calculate the actual time delay data t between the detection white light pulse (CHB signal) and the excitation light pulse (CHA signal) of the pump data collected by each detector each time. The data is as Figure 7 shown.

[0092] In this way, each calculated TA value corresponds to a time delay t value, denoted as TA(t n ). As Figure 8 shown, the system makes <data STEP> according to <scan STEP>;

[0093]

[0094] wherein, t n ’ < t1, t2…t n < t n+1 ).

[0095] As Figure 9 、 10 、11 shown, they are the measured data of this system. It can be seen that the measured data has a high signal-to-noise ratio (less than 0.1 mOD) and a high time resolution (less than 1 ns).

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features, without departing from the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nanosecond transient absorption spectroscopy test system, characterized in that, include: Excitation light source module (I), electro-excitation module (II), detection light source module (III), optical path module (IV) and system control module (V); The excitation light source module (I) comprises: an excitation light source (1) and an optical parametric amplifier (2); the excitation light source (1) emits excitation light, and transmits the excitation light to the optical path module (IV) through the optical parametric amplifier (2); The electro-excitation module (II) comprises: a function signal generator (33); the function signal generator (33) has two channels, the electric pulse signal of the first channel of the function signal generator (33) is applied to the positive and negative electrodes of the sample to perform pump electro-excitation; the electric pulse signal of the second channel of the function signal generator (33) is output to the timing card (31); The detection light source module (III) comprises: a white light laser (8); the white light laser (8) emits white light; the repetition rate of the white light laser (8) is 2 kHz, the pulse width is less than 1 ns, and the spectrum range is 350 nm-2000 nm; The optical path module (IV) comprises: a first optical path, a filter (9), a beam splitter (10), a second optical path, a third optical path, a fourth optical path and a sample displacement stage (21); The first optical path projects the excitation light onto the sample; wherein the sample is placed on a sample displacement stage (21); The filter (9) filters the white light, and the beam splitter (10) splits the white light after filtering. After beam splitting, 20% of the white light is reflected as reference light and enters the system control module (V) through the second optical path; the other 80% of the white light is focused on the sample through the third optical path as detection light, and then becomes parallel light through the fourth optical path and enters the system control module (V); The first optical path comprises: a first reflector (3), a first small hole (4), a first attenuation plate (5), a first plano-convex lens (6) and a second reflector (7) which are arranged in sequence; The second optical path comprises: a third reflector (11), a second attenuation plate (12), a second plano-convex lens (13) and a first optical fiber receiver (14) which are arranged in sequence; The third optical path comprises: a fourth reflector (17), a second small hole (18), a third attenuation plate (19) and a parabolic mirror (20) which are arranged in sequence; The fourth optical path comprises: a third plano-convex lens (22), a detachable reflector (23), a third small hole (24), a fourth plano-convex lens (25), and a second optical fiber receiver (26) arranged in sequence; the fourth optical path also comprises: a fifth reflector (28), a fifth plano-convex lens (34), and a sixth reflector (35) arranged in sequence; the emission direction of the sixth reflector (35) corresponds to that of the detachable reflector (23); The system control module (V) comprises: an industrial computer (32), a timing card (31), a delay calculator (30), a detection spectrometer (27), a detection light detector (29), a reference spectrometer (15) and a reference detector (16); The detection spectrometer (27) is signal-connected to the detection optical detector (29), and the reference spectrometer (15) is signal-connected to the reference detector (16); the timing card (31), the delay calculator (30), the detection optical detector (29), the reference detector (16) and the white light laser (8) are respectively signal-connected to the industrial control computer (32); The reference light enters the reference spectrometer (15) and is incident on the reference detector (16); the detection light enters the detection spectrometer (27) and is incident on the detection optical detector (29); The timing card (31) is respectively signal-connected to the detection optical detector (29), the reference detector (16), the excitation light source (1), the function signal generator (33), the white light laser (8), and the delay calculator (30).

2. The nanosecond transient absorption spectroscopy test system according to claim 1, wherein The excitation light source (1) uses a femtosecond laser or a semiconductor laser; The repetition frequency of the femtosecond laser or the semiconductor laser is 1 KHz, and the wavelength range is 200 nm - 2000 nm.

3. The test method of the nanosecond transient absorption spectroscopy test system according to claim 1 or 2, characterized in that, It includes the following processes: Step 1, the 1 KHz clock signal output by the excitation light source 1 or the function signal generator (33) is input to the timing card (31). The timing card (31) generates a first reference signal and a second reference signal according to the clock signal, then generates a D trigger signal and a P trigger signal according to the first reference signal, and generates a detector trigger signal according to the second reference signal; Step 2, the timing card (31) inputs the D trigger signal and the P trigger signal to the white light laser (8); the detector trigger signal is simultaneously output to the detection optical detector (29) and the reference detector (16); Step 3, according to the timing control of the timing card (31), the system is tested: the excitation light source (1) emits excitation light, and emits it to the optical path module (Ⅳ) through the optical parametric amplifier (2), and the excitation light is incident on the sample through the first optical path for pump-probe photoexcitation; or the electrical pulse signal of the first channel of the function signal generator (33) is applied to the positive and negative electrodes of the sample for pump electroexcitation; The filter (9) filters the white light, and the beam splitter (10) splits the filtered white light; after splitting, 20% of the white light is reflected as the reference light and enters the system control module (Ⅴ) through the second optical path; the other 80% of the white light is used as the detection light, which is focused on the sample through the third optical path, and then becomes parallel light through the fourth optical path and enters the system control module (Ⅴ); the reference light enters the reference spectrometer (15) and is incident on the reference detector (16); the detection light enters the detection spectrometer (27) and is incident on the detection optical detector (29); Step 4, according to the data obtained by the detection optical detector (29) and the reference detector (16), calculate the TA signal value according to the following formula: Wherein, TA(ΔT / T) represents the transient absorption transmittance value, I 1-pump represents the measured value of the probe light detector in the excited state, IRef 1-pump represents the measured value of the reference detector in the excited state, I 1-unpump represents the measured value of the probe light detector in the unexcited state, IRef 1-unpump represents the measured value of the reference detector in the unexcited state; Step 5, calculate the time delay t value corresponding to each TA signal value to obtain the test result of the nanosecond transient absorption spectrum.

4. The test method according to claim 3, characterized in that, The repetition frequency of the first reference signal is 1 KHz, and it has a delay time t1. The delay time t1 is adjustable, and the adjustment range of the delay time t1 is 0 - 500 us; The repetition frequency of the D trigger signal is 2KHz, the delay time is 0us, and the high-level duty cycle is 50%; The repetition frequency of the P trigger signal is 2KHz, the delay time is t3, and the high-level duty cycle is adjustable; The repetition frequency of the second reference signal is 2KHz, and the delay time is t2; The repetition frequency of the detector trigger signal is 2KHz, and the delay time is 0us.

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