Microscopic transient absorption spectroscopy measurement system

Abstract

The application provides a micro-transient absorption spectrum measurement system, comprising: a measurement light source; a first semi-transparent semi-reflective mirror which splits light after receiving the light beam; an excitation light path comprising an optical parametric amplifier and a first focusing lens, wherein a vertical light beam is focused on a sample to be measured after passing through the optical parametric amplifier and the first focusing lens; a detection light path comprising a second focusing lens, a nonlinear crystal, a first band-pass filter, a first off-axis parabolic mirror and a second off-axis parabolic mirror, wherein a horizontal light beam is focused on the sample to be measured after passing through the second focusing lens, the nonlinear crystal, the first band-pass filter, the first off-axis parabolic mirror and the second off-axis parabolic mirror; and a measurement assembly comprising a collimating lens and a spectrometer, wherein focused detection light passes through the sample to be measured and then enters the spectrometer through the collimating lens to be measured. The micro-transient absorption spectrum measurement system provided by the application is based on an off-axis parabolic mirror, is suitable for an incident light beam with a large incident spot area and a wide spectral range, and can significantly reduce the cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical measurement equipment, in particular to a micro-transient absorption spectrum measurement system. BACKGROUND

[0002] With the maturation and wide application of femtosecond laser technology, measuring the transient optical absorption of a substance in the femtosecond to picosecond range is an important research method in physics, materials science, chemistry, and biology. For example, the transient absorption spectrum technology is used to study the exciton dynamics process, interlayer charge transfer process, and energy level fine structure of two-dimensional transition metal sulfide (TMDs). The current transient absorption spectrum system can achieve wide-spectrum and micron spatial resolution transient absorption spectrum measurement.

[0003] The traditional micro-transient absorption spectrum system mainly focuses on the detection light into a micron-sized spot by a microscope objective, achieving micron spatial resolution. This method has the following technical problems:

[0004] 1. Since the general microscope objective is a transmissive optical element, it needs to be coated with a corresponding optical antireflection film, so it can only support a certain narrow band of light, and other bands of light will be greatly lost or even cannot pass through the microscope objective. Moreover, when white light with a wide spectrum passes through the transmissive optical element, dispersion is introduced, which reduces the time resolution of the transient absorption spectrum measurement.

[0005] 2. If a micron-sized focused spot is to be obtained, the working distance of the microscope objective required is very short, and the working distance of an ordinary microscope objective is in the millimeter range, and the working distance of a long-working-distance microscope objective is in the tens of millimeters. This results in that the distance between the microscope objective and the measurement sample is very close, which limits the application in many occasions, such as low-temperature environment and vacuum environment.

[0006] 3. The entrance aperture of most microscope objectives is small, which requires that the diameter of the incident light cannot be too large. Therefore, before the light passes through the microscope objective, it needs to be reduced to an appropriate size so as to completely pass through the microscope objective.

[0007] 4. The microscope objective is expensive, and the unit price is generally tens of thousands to hundreds of thousands of yuan.

[0008] In the background section, the disclosed above information is only used to strengthen the understanding of the background of the present application, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0009] At least one embodiment of the present application provides a micro-transient absorption spectrum measurement system. The micro-transient absorption spectrum measurement system comprises a measurement light source, a first half-transmission half-reflection mirror, an excitation light path, a probe light path, and a measurement assembly.

[0010] The first half-transmission half-reflection mirror splits the measurement light beam emitted by the measurement light source into a horizontal light beam and a vertical light beam after receiving the measurement light beam.

[0011] The excitation light path includes an optical parametric amplifier and a first focusing lens, and the vertical light beam is focused on the sample to be measured by the first focusing lens after changing the light wavelength by the optical parametric amplifier, and the sample to be measured is excited.

[0012] The detection light path includes a second focusing lens, a nonlinear crystal, a first band-pass filter, a first off-axis parabolic mirror, and a second off-axis parabolic mirror. The horizontal light beam is focused on the nonlinear crystal by the second focusing lens to generate supercontinuum light. The supercontinuum light is filtered by the first band-pass filter to form a detection light. The parallel detection light is reflected by the first off-axis parabolic mirror to form parallel detection light. The parallel detection light is reflected by the second off-axis parabolic mirror to form focused detection light and focus on the sample to be measured.

[0013] The measurement assembly includes a collimating lens and a spectrometer. The focused detection light passes through the sample to be measured, is collimated into parallel measurement light by the collimating lens, and enters the spectrometer to measure the spectrum.

[0014] According to some embodiments of the present application, the micro-transient absorption spectrum measurement system further includes an imaging assembly including a microscope objective, a second half-transmission half-reflection mirror, an imaging light source, an imaging lens, and a CCD. The imaging light beam emitted by the imaging light source enters the microscope objective through the second half-transmission half-reflection mirror. The microscope objective focuses the received incident light on the sample to be measured. The sample to be measured reflects the light beam, which passes through the microscope objective, the second half-transmission half-reflection mirror, and the imaging lens in turn, and is imaged on the CCD.

[0015] According to some embodiments of the present application, the micro-transient absorption spectrum measurement system further includes a flip mirror frame. The imaging assembly is coupled to the flip mirror frame, and the imaging assembly can be moved into or out of the light path by moving the flip mirror frame.

[0016] According to some embodiments of the present application, the excitation light path further includes a chopper arranged between the optical parametric amplifier and the first focusing lens. The chopper is used to modulate the continuous light beam into a light beam with a fixed frequency.

[0017] According to some embodiments of the present application, the excitation light path further includes a first mirror array arranged between the optical parametric amplifier and the first focusing lens. The vertical light beam changes the light wavelength by the optical parametric amplifier and is reflected to the first focusing lens via the first mirror array.

[0018] According to some embodiments of the present application, the excitation light path further comprises: the probe light path further comprises: an optical delay component comprising a second mirror array, disposed between the first half-transmission half-reflection mirror and the second focusing lens.

[0019] According to some embodiments of the present application, the optical delay component further comprises a driver coupled with the second mirror array, for adjusting the position of the second mirror array.

[0020] According to some embodiments of the present application, the probe light path further comprises: a beam expansion collimation component comprising a third off-axis parabolic mirror and a fourth off-axis parabolic mirror, disposed between the second off-axis parabolic mirror and the sample to be measured, the probe light passes through the first off-axis parabolic mirror, the second off-axis parabolic mirror, the third off-axis parabolic mirror and the fourth off-axis parabolic mirror in sequence to be focused on the sample to be measured.

[0021] According to some embodiments of the present application, the measurement component further comprises: a second band-pass filter, the focused probe light passes through the sample to be measured, collimated by the collimating lens into parallel measurement light, and enters the spectrometer to measure the spectrum after being filtered by the second band-pass filter.

[0022] According to some embodiments of the present application, the focal spot radius of the first off-axis parabolic mirror and / or the second off-axis parabolic mirror is:

[0023]

[0024] wherein r is the focal spot radius, λ is the wavelength of the incident light, f is the focal length, and R is the spot radius of the incident light.

[0025] The micro-region transient absorption spectrum measurement system of the present application is based on off-axis parabolic mirrors, which overcomes a series of problems brought by microscopes, is suitable for incident light beams with large spot area and wide spectral range, and is inexpensive, which can significantly reduce the cost.

[0026] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description only some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0028] Figure 1 The structural schematic diagram of a micro-transient absorption spectrum measurement system according to some embodiments of the present application is shown.

[0029] Figure 2 The structural schematic diagram of a micro-transient absorption spectrum measurement system according to some embodiments of the present application is shown.

[0030] Figure 3 The structural schematic diagram of a micro-transient absorption spectrum measurement system according to some embodiments of the present application is shown. DETAILED DESCRIPTION

[0031] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments may, however, be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the description. Repetitive descriptions of like elements will be omitted for sake of brevity.

[0032] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. However, one skilled in the relevant art will recognize that the

[0033] The flow charts shown in the drawings are only exemplary and do not necessarily include all of the contents and operations / steps, nor do they have to be executed in the order described. For example, some operations / steps can be further broken down, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0034] The terms "first", "second", and the like in the description and in the claims of the present application and above-described drawings are used to distinguish different objects, and are not used to describe a particular order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device including a series of steps or units is not limited to the listed steps or units, but can optionally further include steps or units not listed, or can optionally further include other steps or units inherent to the process, method, product, or device.

[0035] The conventional micro-transient absorption spectroscopy system is mainly based on a microscope objective to focus the probe light into a micron-level light spot, so as to realize micron-level spatial resolution. This method has the following technical problems:

[0036] 1. Since the general microscope objective is a transmission optical element, a corresponding optical antireflection film needs to be evaporated, so that only light in a relatively narrow waveband can pass through the microscope objective, and light in other wavebands will have a large loss or even cannot pass through the microscope objective when passing through the microscope objective. Moreover, when the white light of a wide spectral waveband passes through the transmission optical element, dispersion will be introduced, thereby reducing the time resolution in the transient absorption spectroscopy measurement.

[0037] 2. If a micron-level focused light spot is to be obtained, the working distance of the microscope objective required is very short. The working distance of an ordinary microscope objective is in the order of millimeters, and the working distance of a long-working-distance microscope objective is in the order of tens of millimeters. This results in that the distance between the microscope objective and the measurement sample is very close, thereby limiting the application in many occasions, such as a low-temperature environment, a vacuum environment, and the like.

[0038] 3. The entrance aperture of most microscope objectives is small, which requires that the diameter of the incident light cannot be too large. Therefore, before the light passes through the microscope objective, it needs to be reduced to a suitable size so as to completely pass through the microscope objective.

[0039] 4. The microscope objective is expensive, and the unit price is generally tens of thousands to hundreds of thousands of yuan.

[0040] The inventors of the present application find that a micro-transient absorption spectroscopy measurement system can be built based on an off-axis parabolic mirror. Compared with the conventional method of realizing micro-detection by using a microscope objective, the off-axis parabolic mirror overcomes a series of problems brought by the microscope objective, is suitable for an incident light beam with a large light spot area and a wide spectral range, and is inexpensive, so that the cost can be significantly reduced.

[0041] Off Axis Parabolic Mirror (OAP) is one of the common elements for building terahertz and infrared optical path. Based on the principle of geometric parabolic mirror, it can focus the collimated light beam / THz wave to the focal point, and also can convert the THz wave or infrared light emitted by point light source into parallel transmission light beam. The off-axis parabolic mirror is made of aluminum and processed by precision metal cutter, so it works by reflection and can eliminate the phase delay and absorption loss of transmission optical elements.

[0042] The micro-transient absorption spectrum measurement system according to the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0043] Figure 1 The structure diagram of the micro-transient absorption spectrum measurement system according to the example embodiments of the present application is shown.

[0044] Referring to Figure 1 , the micro-transient absorption spectrum measurement system of the example embodiments includes a measurement light source 110, a first half-transmission half-reflection mirror 120, an excitation light path 130, a probe light path 140, a measurement assembly 150, and an imaging assembly 160.

[0045] As shown in Figure 1 , the first half-transmission half-reflection mirror 120 splits the measurement light beam emitted by the measurement light source 110 into a horizontal light beam and a vertical light beam.

[0046] The excitation light path 130 includes an optical parametric amplifier 131 and a first focusing lens 132. The vertical light beam obtained by splitting by the first half-transmission half-reflection mirror 120 is changed in wavelength by the optical parametric amplifier 131 and focused on the sample to be measured 200 by the first focusing lens 132 to excite the sample to be measured 200.

[0047] The probe light path 140 includes a second focusing lens 141, a nonlinear crystal 142, a first band-pass filter 143, a first off-axis parabolic mirror 144, and a second off-axis parabolic mirror 145. The horizontal light beam is focused on the nonlinear crystal 142 by the second focusing lens 141 to generate supercontinuum light. The supercontinuum light is filtered by the first band-pass filter 143 to form probe light, and the probe light is reflected by the first off-axis parabolic mirror 144 to form parallel probe light. The parallel probe light is reflected by the second off-axis parabolic mirror 145 to form focused probe light and focus on the sample to be measured 200.

[0048] The nonlinear crystal 142 can be configured as any nonlinear crystal required for measuring micro-transient absorption spectrum. Optionally, the nonlinear crystal 142 is a sapphire crystal. Due to the optical nonlinear effect, the horizontal light beam will generate supercontinuum white light after passing through the sapphire crystal.

[0049] The measurement assembly 150 includes a collimating lens 151 and a spectrometer 152. The focused probe light, after passing through the sample 200 to be measured, is collimated by the collimating lens 151 into parallel measurement light and enters the spectrometer 152 to measure the spectrum.

[0050] The imaging assembly 160 includes a microscope objective 161, a second half-mirror 162, an imaging light source 163, an imaging lens 164, and a CCD 165.

[0051] The imaging light beam emitted by the imaging light source 163 passes through the second half-mirror 162 and enters the microscope objective 161. The microscope objective 161 focuses the received incident light on the sample 200 to be measured. The sample 200 to be measured reflects the light beam, which passes through the microscope objective 161, the second half-mirror 162, and the imaging lens 164 in turn, and is finally imaged on the CCD 165.

[0052] Through the setting state of the imaging assembly 160, the surface of the sample 200 to be measured can be observed. When the probe light is focused on the surface of the sample 200 to be measured by the first off-axis parabolic mirror 144 and the second off-axis parabolic mirror 145, the microscope objective 161 can observe the focal spot of the probe light while observing the surface of the sample 200 to be measured, so as to determine the shape and size of the focal spot.

[0053] Optionally, taking the focal length of the second off-axis parabolic mirror 145 as an example, the focal length is 76 mm and the diameter is 50 mm. In actual application, an ultraviolet enhancement aluminum film is coated on the surface of the off-axis parabolic mirror. According to the focal spot radius formula, the focal spot size of the probe light after passing through the second off-axis parabolic mirror 145 can be calculated, that is, the focal spot radius of the second off-axis parabolic mirror 145 is:

[0054]

[0055] Wherein, r is the focal spot radius, λ is the wavelength of the incident light, f is the focal length, and R is the spot radius of the incident light.

[0056] The off-axis parabolic mirror and the conventional microscope objective can be compared. The specific comparison results are shown in the following table:

[0057]

[0058] As can be seen from the table, the off-axis parabolic mirror significantly overcomes the shortcomings of the short working distance and small entrance pupil diameter of the microscope objective. And the reflectivity in the wavelength range of 350nm-980nm is greater than 75%. Moreover, the transmittance of the microscope objective gradually decreases beyond the visible light range. If a higher transmittance in the ultraviolet or infrared wavelength range is required, the microscope objective needs to be replaced.

[0059] In addition, the off-axis parabolic mirror does not introduce optical dispersion, while the microscope objective is a transmissive optical element. When white light passes through the microscope objective, different wavelengths of light will introduce dispersion due to the difference in refractive index. Therefore, compared with the microscope objective, the off-axis parabolic mirror is very suitable for focusing white light, which is a wide-spectrum light source, to realize the measurement of micro-transient absorption spectroscopy.

[0060] Optionally, the measurement light source 110 is configured as a commercial femtosecond laser.

[0061] It can be understood that the corresponding relationship between the horizontal light beam, the vertical light beam and the excitation light path and the probe light path can be transposed according to the setting state of the light path, and the present application does not make specific corresponding limitations.

[0062] Figure 2 A structural schematic diagram of a micro-transient absorption spectroscopy measurement system according to some embodiments of the present application is shown.

[0063] Referring to Figure 2 The micro-transient absorption spectroscopy measurement system of some embodiments includes a measurement light source 110, a first half-transmission half-reflection mirror 120, an excitation light path 130, a probe light path 140, a measurement assembly 150, an imaging assembly 160 and a flip mirror holder 170.

[0064] As Figure 2 shown, the first half-transmission half-reflection mirror 120 receives the measurement light beam emitted by the measurement light source 110 and splits it into a horizontal light beam and a vertical light beam.

[0065] The excitation light path 130 includes an optical parametric amplifier 131, a first focusing lens 132, a chopper 133 and a first mirror array 134. After the vertical light beam passes through the commercial optical parametric amplifier 131, the wavelength of the light beam changes. By setting the parameters, the required wavelength of light in the experiment can be obtained. This femtosecond laser acts as a pump laser. After the pump laser passes through the chopper 133, it enters the surface of the sample to be measured 200 after passing through the first mirror array 134 and the first focusing lens 132, and excites the sample.

[0066] The chopper 133 is arranged between the optical parametric amplifier 131 and the first mirror array 134, and is configured to modulate the continuous light beam into a light beam with a fixed frequency. The first mirror array 134 is configured to reflect the light beam modulated by the chopper 133 to the first focusing lens 132.

[0067] According to the arrangement state of the light path, the first mirror array 134 can be configured to have any number of mirrors to reflect and transmit the excitation light beam. Optionally, the first mirror array 134 includes three mirrors.

[0068] The probe light path 140 includes a second focusing lens 141, a nonlinear crystal 142, a first band-pass filter 143, a first off-axis parabolic mirror 144, a second off-axis parabolic mirror 145, and an optical delay component 146.

[0069] The horizontal light beam is first incident into the optical delay component 146, and is focused by the second focusing lens 141 to the nonlinear crystal 142 after being delayed by the optical delay component 146 to generate supercontinuum light. The supercontinuum light is filtered by the first band-pass filter 143 to form probe light, and the probe light is reflected by the first off-axis parabolic mirror 144 to form parallel probe light. The parallel probe light is reflected by the second off-axis parabolic mirror 145 to form focused probe light and focus on the sample 200 to be measured.

[0070] The optical delay component 146 can be configured as any optical component that can delay the time of incidence of the horizontal light beam. By adjusting the optical delay component 146, the time delay between the excitation light path and the probe light path can be changed, so that the transient absorption spectrum at different times can be obtained.

[0071] Optionally, the optical delay component 146 includes a second mirror array 1461 and a driver 1462. The optical delay component 146 is arranged between the first half-transmission half-reflection mirror 120 and the second focusing lens 141, and the driver 1462 is coupled with the second mirror array 1461 to conveniently adjust the position state of the second mirror array 1461. By adjusting the driver 1462, the delay effect of the optical delay component 146 can be conveniently adjusted. According to the requirements of the measurer, the transient absorption spectrum at different times can be obtained by adjustment.

[0072] The imaging component 160 includes a microscope objective 161, a second half-transmission half-reflection mirror 162, an imaging light source 163, an imaging lens 164, a CCD 165, and an imaging mirror 166.

[0073] The imaging light beam emitted by the imaging light source 163 enters the microscopic objective 161 after passing through the second half-transmission half-reflection mirror 162 and the imaging reflection mirror 166, and the microscopic objective 161 focuses the received incident light on the sample 200 to be measured. The sample 200 to be measured reflects the light beam, which passes through the microscopic objective 161, the imaging reflection mirror 166, the second half-transmission half-reflection mirror 162 and the imaging lens 164 in sequence, and is finally imaged on the CCD 165.

[0074] The flip frame 170 is coupled to the imaging assembly 160, and the imaging assembly 160 can be moved into or out of the light path by moving the flip frame 170. When the imaging assembly 160 is moved into the light path, the measurement assembly 150 can be moved out of the light path, so that the imaging and measurement functions of the micro-transient absorption spectrum measurement system do not interfere with each other. Similarly, when the imaging assembly 160 is moved out of the light path, the measurement assembly 150 can be moved into the light path.

[0075] The measurement assembly 150 includes a collimating lens 151, a spectrometer 152 and a second band-pass filter 153. After the focused probe light passes through the sample 200 to be measured, it is collimated into parallel measurement light by the collimating lens 151, and then enters the spectrometer 152 after being filtered by the second band-pass filter 153 to measure the spectrum.

[0076] Figure 3 A structural schematic diagram of a micro-transient absorption spectrum measurement system according to another embodiment of the present application is shown.

[0077] Referring to Figure 3 , the micro-transient absorption spectrum measurement system of another embodiment includes a light source 110, a first half-transmission half-reflection mirror 120, an excitation light path 130, a probe light path 140, a measurement assembly 150, an imaging assembly 160 and a flip frame 170.

[0078] Unlike the micro-transient absorption spectrum measurement system shown in Figure 2 , the probe light path 140 includes a second focusing lens 141, a nonlinear crystal 142, a first band-pass filter 143, a first off-axis parabolic mirror 144, a second off-axis parabolic mirror 145, a light delay assembly 146 and a beam expansion collimating assembly 147.

[0079] The beam expansion collimating assembly 147 includes a third off-axis parabolic mirror 1471 and a fourth off-axis parabolic mirror 1472, and is arranged between the first off-axis parabolic mirror 144 and the second off-axis parabolic mirror 145. The probe light passes through the first off-axis parabolic mirror 144, the third off-axis parabolic mirror 1471, the fourth off-axis parabolic mirror 1472 and the second off-axis parabolic mirror 145 in sequence to be focused on the sample 200 to be measured.

[0080] By adding the beam expanding collimating assembly 147 in the probe light path 140, the size of the light spot incident on the second off-axis parabolic mirror 145 can be increased, so that a smaller size of the focal spot on the sample under test 200 can be further obtained.

[0081] The exemplary embodiments of this application are specifically shown and described above. It is to be understood that this application is not limited to the details of the foregoing description, nor to the precise construction or the implementation method described herein; rather, this application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A micro-area transient absorption spectroscopy measurement system, characterized in that: include: Measuring light sources; a first semi-transparent and semi-reflective mirror, configured to receive the measuring light beam emitted by the measuring light source and split the beam into a horizontal light beam and a vertical light beam; An excitation optical path includes an optical parametric amplifier and a first focusing lens. After the wavelength of the vertical light beam is changed by the optical parametric amplifier, the first focusing lens focuses the vertical light beam on the sample to be measured and excites the sample to be measured. A detection optical path includes a second focusing lens, a nonlinear crystal, a first bandpass filter, a first off-axis parabolic reflector, and a second off-axis parabolic reflector. The horizontal light beam is focused on the nonlinear crystal by the second focusing lens to generate supercontinuum light. The supercontinuum light is filtered by the first bandpass filter to form detection light. The detection light is reflected by the first off-axis parabolic reflector to form parallel detection light. The parallel detection light is reflected by the second off-axis parabolic reflector to form focused detection light and is focused on the sample to be measured. The detection optical path further includes: a beam expansion and collimation component, including a third off-axis parabolic reflector and a fourth off-axis parabolic reflector, which is arranged between the second off-axis parabolic reflector and the sample to be measured, and the detection light is adjusted by the first off-axis parabolic reflector, the second off-axis parabolic reflector, the third off-axis parabolic reflector and the fourth off-axis parabolic reflector in sequence and then focused on the sample to be measured; The measuring component includes a collimating lens and a spectrometer. After the focused detection light passes through the sample to be measured, it is collimated by the collimating lens to become parallel measuring light and enters the spectrometer to measure the spectrum.

2. The micro-area transient absorption spectroscopy measurement system according to claim 1, characterized in that: Also includes: Imaging assembly, including microscope objective lens, second semi-transparent and semi-reflective mirror, imaging light source, imaging lens and CCD; Among them, the imaging light beam emitted by the imaging light source enters the microscope objective lens after passing through the second semi-transparent and semi-reflective mirror, and the microscope objective lens focuses the received incident light on the sample to be tested. The sample to be tested reflects the light beam and passes through the microscope objective lens, the second semi-transparent and semi-reflective mirror and the imaging lens in sequence, and is imaged on the CCD.

3. The micro-area transient absorption spectroscopy measurement system according to claim 2, characterized in that: Also includes: A flip mirror frame is provided, to which the imaging assembly is coupled, and the imaging assembly can be moved into or out of the optical path by moving the flip mirror frame.

4. The micro-area transient absorption spectroscopy measurement system according to claim 1, characterized in that: The excitation light path further includes: A chopper is provided between the optical parametric amplifier and the first focusing lens, and is used for modulating a continuous light beam into a light beam with a fixed frequency.

5. The micro-area transient absorption spectroscopy measurement system according to claim 1, characterized in that: The excitation light path further includes: The first reflector array is arranged between the optical parametric amplifier and the first focusing lens. After the wavelength of the vertical light beam is changed by the optical parametric amplifier, the vertical light beam is reflected to the first focusing lens via the first reflector array.

6. The micro-area transient absorption spectroscopy measurement system according to claim 1, characterized in that: The detection optical path also includes: The optical delay component includes a second reflector array, which is arranged between the first semi-transparent and semi-reflective mirrors and the second focusing lens.

7. The micro-area transient absorption spectroscopy measurement system according to claim 6, characterized in that: The optical delay component further includes a driver coupled to the second reflector array for adjusting a position of the second reflector array.

8. The micro-area transient absorption spectroscopy measurement system according to claim 1, characterized in that: The measuring component further comprises: The second bandpass filter is used for the focused detection light to pass through the sample to be measured and then be collimated by the collimating lens into parallel measurement light. The parallel measurement light is filtered by the second bandpass filter and then enters the spectrometer to measure the spectrum.

9. The micro-area transient absorption spectroscopy measurement system according to any one of claims 1 to 8, characterized in that: The focal spot radius of the first off-axis parabolic reflector and / or the second off-axis parabolic reflector is: Where r is the focal spot radius, λ is the wavelength of the incident light, f is the focal length, and R is the spot radius of the incident light.

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