A transient spectroscopy system for measuring the characteristics of amplified stimulated emission

Abstract

The present invention relates to an instantaneous spectroscopy system for measuring amplified stimulated emission characteristics, and belongs to the field of time-resolved nonlinear optical spectroscopy. The present invention is composed of a pump laser generation and adjustment part, a disturbance laser generation and adjustment part, and a sample excitation and signal collection part to be measured. A beam of femtosecond laser is used to excite one end of a solution sample in an optical fiber or one side of a thin film sample, and another beam of femtosecond laser is used to irradiate the sample in the same direction after a certain delay time to disturb the sample, so as to explore the threshold conditions and various disturbance factors that can cause the sample to produce amplified stimulated emission. The present invention is aimed at studying some potential chiral materials, and a variety of amplified stimulated emission characteristics research methods can be realized by this system. The use of this system can more comprehensively and deeply explore the amplified stimulated emission characteristics of various substances.

Description

Technical Field

[0001] The invention belongs to the field of time-resolved nonlinear optical spectroscopy, and in particular relates to an instantaneous spectroscopy system for measuring amplified stimulated emission characteristics. Background Art

[0002] Under the action of light, three processes occur between the ground state and the excited state: absorption, stimulated emission and spontaneous emission. For stimulated emission, it is a transition state between laser and spontaneous emission light, which is inherent in all laser systems. When the number of particles is reversed, the photons of spontaneous emission induce more excited states to transition to the ground state, thereby amplifying spontaneous emission. Particle population inversion is generally easier to achieve in samples of multi-level systems. Take the three-level system as an example. The excitation light excites electrons from the ground state to the excited state energy level. The excited state energy level has a short lifetime, and the electrons will relax to the metastable state energy level in a very short time. Therefore, the metastable state energy level and the ground state energy level achieve a particle population inversion. At this time, under the action of a photon with an energy size equal to the energy difference between the metastable state energy level and the stable state energy level (the same size as the spontaneous radiation photon), the electrons jump from the metastable state energy level to the ground state energy level and emit a second photon of the same energy. After that, these two photons continue to act to excite more identical photons. This "avalanche-like" stimulated radiation generates photons, which have properties similar to lasers, but do not have the coherence of real lasers. After that, it can become a real laser by introducing resonant feedback and other methods. Therefore, exploring materials with the potential to be used as laser resonators has become one of the research hotspots, and the research on the stimulated emission characteristics of materials is also increasing.

[0003] In 2014, low-threshold and stable room-temperature amplified spontaneous emission in perovskite thin films was first reported. Since then, a large number of studies have explored the amplified spontaneous emission and lasers of thin films and low-dimensional materials, and lowered the threshold and increased the gain. The common research method is to use a continuous laser to emit continuous laser light, which is converted into strip light after passing through a cylindrical lens to excite the material to study the amplified spontaneous emission characteristics of the material, especially the threshold problem of the material producing amplified spontaneous emission characteristics. Based on the principle of amplified spontaneous emission, we have developed a new system that uses a beam of adjustable laser-induced radiation to replace spontaneous emission photons to stimulate more photons, turning amplified spontaneous emission into amplified stimulated emission. The system uses two femtosecond lasers with ultrashort pulses. The first laser excites the sample to a high energy state. The particles in the high energy state will transition to other energy levels over time. The second laser reaches the sample at different time intervals from the first laser to perturb it, and stimulated emission signals of different intensities can be obtained, and finally the kinetic information related to stimulated emission is measured. In addition, the excitation frequency and excitation power of the two laser beams can also be adjusted; the excitation light frequency can be adjusted through an optical parametric amplifier, and the excitation power can be adjusted through an attenuator, etc., to explore the frequency and power at which the amplified spontaneous emission phenomenon occurs, so as to study the amplified stimulated emission properties of the material more carefully and clearly. By adjusting the relative time between the two laser beams, amplified stimulated emission signals of different intensities are obtained, and finally the kinetic information related to amplified stimulated emission is measured. Summary of the invention

[0004] The present invention provides an instantaneous spectroscopy system for measuring amplified stimulated emission characteristics, which uses two beams of femtosecond light, one for excitation and the other for disturbance, to explore the amplified stimulated emission threshold conditions of solution samples or thin film samples in optical fibers.

[0005] The technical scheme adopted by the present invention is that it consists of a pump laser generating and regulating part I, a disturbance laser generating and regulating part II and a sample excitation and signal collection part III; the pump laser generating and regulating part I, the disturbance laser generating and regulating part II and the sample excitation and signal collection part III are all placed on the same optical platform except for a spectrometer, an oscilloscope, a phase-locked amplifier and a computer; the disturbance laser generating and regulating part II is located at the rear right front of the pump laser generating and regulating part I, and half surrounds the pump laser generating and regulating part I; the sample excitation and signal collection part III is located at the front left of the pump laser generating and regulating part I and the disturbance laser generating and regulating part II, and the beam splitter of the pump laser generating and regulating part I is connected to the total reflection mirror 4 of the disturbance laser generating and regulating part II through an optical path; the dichroic mirror 1 of the sample excitation and signal collection part III is located at the pump laser generating and regulating part I In front of the quarter wave plate one in the sample excitation and signal collection part III, the dichroic mirror one and the quarter wave plate one are located on the same horizontal center line, and the quarter wave plate one and the dichroic mirror one are connected through an optical path; the dichroic mirror one of the sample excitation and signal collection part III to be tested is located on the left of the total reflection mirror eight in the disturbance laser generation and adjustment part II, and the dichroic mirror one and the total reflection mirror eight are located on the same horizontal center line, and the total reflection mirror eight is connected to the dichroic mirror one through an optical path; the electric control displacement stage signal output port b and the chopper signal output port a of the pump laser generation and adjustment part I are respectively connected to the computer signal input port o and the phase-locked amplifier signal input port k of the sample excitation and signal collection part III to be tested through cables, and the femtosecond laser signal output port c of the pump laser generation and adjustment part I are respectively connected to the oscilloscope signal input port d and the CCD signal input port h of the sample excitation and signal collection part III to be tested through cables.

[0006] The pump laser generating and regulating part I of the present invention is composed of a femtosecond laser, a beam splitter, an optical parametric amplifier 1, a total reflection mirror 1, an electrically controlled displacement stage, a chopper, a total reflection mirror 2, a total reflection mirror 3, a Glan prism 1 and a quarter wave plate 1, wherein the electrically controlled displacement stage is provided with an output port b, and the chopper is provided with an output port a; the femtosecond laser, the beam splitter, the optical parametric amplifier 1 and the total reflection mirror 1 are arranged in sequence from left to right; the electrically controlled displacement stage, the chopper, the total reflection mirror 2 and the total reflection mirror 1 are arranged in sequence from front to back; the total reflection mirror 3, the Glan prism 1 and the quarter wave plate 1 are arranged in sequence from back to front, and the total reflection mirror 3, the Glan prism 1 and the quarter wave plate 1 are located on the same horizontal center line.

[0007] The beam splitter described in the present invention is a 9:1 beam splitter, which can make the ratio of the intensity of transmitted and reflected light be 9:1.

[0008] The disturbance laser generating and regulating part II described in the present invention is composed of a total reflection mirror four, an optical parametric amplifier two, a total reflection mirror five, a total reflection mirror six, a total reflection mirror seven, a Glan prism two, a quarter wave plate two and a total reflection mirror eight, wherein the total reflection mirror four, the optical parametric amplifier two and the total reflection mirror five are arranged from left to right, and the total reflection mirror four, the optical parametric amplifier two and the total reflection mirror five are located on the same horizontal center line; the total reflection mirror six is ​​located in front of the total reflection mirror five, and the total reflection mirror seven is located on the left of the total reflection mirror six; the total reflection mirror seven, the Glan prism two, the quarter wave plate two and the total reflection mirror eight are arranged from front to back, and the total reflection mirror seven, the Glan prism two, the quarter wave plate two and the total reflection mirror eight are located on the same horizontal center line.

[0009] The sample excitation and signal collection part III of the present invention is composed of a dichroic mirror 1, a total reflection mirror 9, a movable optical path panel A and a movable optical path panel B, a spectrometer, an oscilloscope, a phase-locked amplifier and a computer, wherein the total reflection mirror 9 is located in front of the dichroic mirror 1 and is located on the same horizontal center line; the spectrometer includes a photomultiplier tube and a CCD; the photomultiplier tube is provided with a signal output port q and a signal output port g; the CCD is provided with a signal input port h and a signal output port i; the oscilloscope is provided with a signal input port d, a signal output port e and a signal input port f; the phase-locked amplifier The amplifier is provided with a signal input port j, a signal output port l, and a signal input port k; the computer is provided with a signal input port m, a signal input port n, a signal input port o, and a signal input port p; the photomultiplier tube signal output port q is connected to the phase-locked amplifier signal input port j; the photomultiplier tube signal output port g is connected to the oscilloscope signal input port f; the CCD signal output port i is connected to the computer signal input port m; the oscilloscope signal output port e is connected to the computer signal input port n; the phase-locked amplifier signal output port l is connected to the computer signal input port p.

[0010] The movable optical path panel A described in the present invention is composed of an objective lens 1, a tubular microcavity such as an optical fiber or a capillary, an objective lens 2 and a dichroic mirror 2. The objective lens 1, the tubular microcavity such as an optical fiber or a capillary, the objective lens 2 and the dichroic mirror 2 are arranged from right to left, and the objective lens 1, the tubular microcavity such as an optical fiber or a capillary, the objective lens 2 and the dichroic mirror 2 are located on the same horizontal center line.

[0011] The movable optical path panel B described in the present invention is composed of a cylindrical mirror, a concave mirror, a sample stage, a lens, a filter and a total reflector ten, wherein the cylindrical mirror, the concave mirror and the sample stage are arranged from right to left, and the cylindrical mirror and the concave mirror are arranged perpendicular to the sample stage; the sample stage, the lens, the filter and the total reflector ten are arranged from back to front, and the sample stage, the lens, the filter and the total reflector ten are located on the same horizontal center line.

[0012] The advantage of the present invention is that a femtosecond laser is used to excite one end of the solution sample in the optical fiber or one side of the thin film sample, and another femtosecond laser is used to irradiate the sample in the same direction after a certain delay time to disturb the sample, so as to explore the threshold conditions and various disturbance factors that can cause the sample to produce amplified stimulated emission. The wavelength of the excitation light beam can be adjusted by TOPAS, and the threshold wavelength that can produce amplified stimulated emission is explored when other conditions remain unchanged; the excitation light power can be adjusted by using attenuation plates and other methods to explore the minimum power (laser light intensity) that can produce amplified stimulated emission; after the first laser excites the sample to reach a high energy level, the delay time of the two beams of light can be adjusted by an electrically controlled displacement stage, and the second beam of light is used to disturb the sample to explore the delay time range that can produce amplified stimulated emission; the present invention also places a detachable polarization device on the two beams of light path, which can convert the laser into circularly polarized light, and can be used to study some potential chiral materials. There are also a variety of amplified stimulated emission characteristics research methods that can be implemented by this system, and the use of this system can more comprehensively and deeply explore the amplified stimulated emission characteristics of various substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0014] Figure 2 It is a schematic diagram of the structure of the pump laser generating and regulating part I of the present invention;

[0015] Figure 3 It is a schematic diagram of the structure of the disturbance laser generating and regulating part II of the present invention;

[0016] Figure 4 It is a schematic diagram of the structure of the sample excitation and signal collection part III of the present invention. DETAILED DESCRIPTION

[0017] like Figure 1As shown, it is composed of a pump laser generating and regulating part I, a disturbance laser generating and regulating part II and a sample excitation and signal collection part III; except for a spectrometer 31, an oscilloscope 34, a phase-locked amplifier 35 and a computer 36, the pump laser generating and regulating part I, the disturbance laser generating and regulating part II and the sample excitation and signal collection part III are all placed on the same optical platform; the disturbance laser generating and regulating part II is located at the rear right front of the pump laser generating and regulating part I, and half surrounds the pump laser generating and regulating part I; the sample excitation and signal collection part III is located at the front left of the pump laser generating and regulating part I and the disturbance laser generating and regulating part II, and the beam splitter 2 of the pump laser generating and regulating part I is connected to the full reflection mirror 4 11 of the disturbance laser generating and regulating part II through an optical path; the dichroic mirror 19 of the sample excitation and signal collection part III is located in front of the quarter wave plate 10 in the pump laser generating and regulating part I , and the dichroic mirror 19 and the quarter wave plate 10 are located on the same horizontal center line, and the quarter wave plate 10 and the dichroic mirror 19 are connected through an optical path; the dichroic mirror 19 of the sample excitation and signal collection part III to be tested is located on the left of the total reflection mirror 8 18 in the disturbance laser generation and adjustment part II, and the dichroic mirror 19 and the total reflection mirror 8 18 are located on the same horizontal center line, and the total reflection mirror 8 18 and the dichroic mirror 19 are connected through an optical path; the signal output port b of the electric control displacement stage 5 and the signal output port a of the chopper 6 of the pump laser generation and adjustment part I are respectively connected to the signal input port o of the computer 36 and the signal input port k of the phase-locked amplifier 35 of the sample excitation and signal collection part III to be tested through cables, and the signal output port c of the femtosecond laser 1 of the pump laser generation and adjustment part I are respectively connected to the signal input port d of the oscilloscope 34 and the signal input port h of the CCD 33 of the sample excitation and signal collection part III to be tested through cables.

[0018] like Figure 2 As shown, the pump laser generation and adjustment part I is composed of a femtosecond laser 1, a beam splitter 2, an optical parametric amplifier 13, a total reflection mirror 14, an electrically controlled displacement stage 5, a chopper 6, a total reflection mirror 27, a total reflection mirror 38, a Glan prism 19 and a quarter wave plate 10, wherein the electrically controlled displacement stage 5 is provided with an output port b, and the chopper 6 is provided with an output port a; the femtosecond laser 1, the beam splitter 2, the optical parametric amplifier 13, and the total reflection mirror 14 are arranged in sequence from left to right; the electrically controlled displacement stage 5, the chopper 6, the total reflection mirror 27 and the total reflection mirror 14 are arranged in sequence from front to back; the total reflection mirror 38, the Glan prism 19 and the quarter wave plate 10 are arranged in sequence from back to front, and the total reflection mirror 38, the Glan prism 19 and the quarter wave plate 10 are located on the same horizontal center line.

[0019] The beam splitter 2 is a 9:1 beam splitter, which can make the ratio of the intensity of transmitted and reflected light be 9:1.

[0020] like Figure 3 As shown, the disturbance laser generation and adjustment part II is composed of a total reflection mirror four 11, an optical parametric amplifier two 12, a total reflection mirror five 13, a total reflection mirror six 14, a total reflection mirror seven 15, a Glan prism two 16, a quarter wave plate two 17 and a total reflection mirror eight 18, wherein the total reflection mirror four 11, the optical parametric amplifier two 12 and the total reflection mirror five 13 are arranged from left to right, and the total reflection mirror four 11, the optical parametric amplifier two 12 and the total reflection mirror five 13 are located on the same horizontal center line; the total reflection mirror six 14 is located in front of the total reflection mirror five 13, and the total reflection mirror seven 15 is located on the left of the total reflection mirror six 14; the total reflection mirror seven 15, the Glan prism two 16, the quarter wave plate two 17 and the total reflection mirror eight 18 are arranged from front to back, and the total reflection mirror seven 15, the Glan prism two 16, the quarter wave plate two 17 and the total reflection mirror eight 18 are located on the same horizontal center line.

[0021] like Figure 4 As shown, the sample excitation and signal collection part III is composed of a dichroic mirror 19, a total reflection mirror 9 20, a movable optical path panel A and a movable optical path panel B, a spectrometer 31, an oscilloscope 34, a phase-locked amplifier 35 and a computer 36, wherein the total reflection mirror 9 20 is located in front of the dichroic mirror 19 and is located on the same horizontal center line; the spectrometer 31 includes a photomultiplier tube 32 and a CCD 33; the photomultiplier tube 32 is provided with a signal output port q and a signal output port g; the CCD 33 is provided with a signal input The oscilloscope 34 is provided with a signal input port d, a signal output port e, and a signal input port f; the lock-in amplifier 35 is provided with a signal input port j, a signal output port l, and a signal input port k; the computer 36 is provided with a signal input port m, a signal input port n, a signal input port o, and a signal input port p; the signal output port q of the photomultiplier tube 32 is connected to the signal input port j of the lock-in amplifier 35; the signal output port g of the photomultiplier tube 32 is connected to the signal input port f of the oscilloscope 34; the signal output port i of the CCD 33 is connected to the signal input port m of the computer 36; the signal output port e of the oscilloscope 34 is connected to the signal input port n of the computer 36; the signal output port l of the lock-in amplifier 35 is connected to the signal input port p of the computer 36.

[0022] The movable optical path panel A described in the present invention is composed of an objective lens 1 21, a tubular microcavity 22 such as an optical fiber or a capillary, an objective lens 23 and a dichroic mirror 24. The objective lens 1 21, the tubular microcavity 22 such as an optical fiber or a capillary, the objective lens 23 and the dichroic mirror 24 are arranged from right to left, and the objective lens 1 21, the tubular microcavity 22 such as an optical fiber or a capillary, the objective lens 23 and the dichroic mirror 24 are located on the same horizontal center line.

[0023] The movable optical path panel B described in the present invention is composed of a cylindrical mirror 25, a concave mirror 26, a sample stage 27, a lens 28, a filter 29 and a total reflector 10 30, wherein the cylindrical mirror 25, the concave mirror 26 and the sample stage 27 are arranged from right to left, and the cylindrical mirror 25 and the concave mirror 26 are arranged perpendicular to the sample stage 27; the sample stage 27, the lens 28, the filter 29 and the total reflector 10 30 are arranged from back to front, and the sample stage 27, the lens 28, the filter 29 and the total reflector 10 30 are located on the same horizontal center line.

[0024] Working principle:

[0025] The femtosecond laser 1 outputs a femtosecond laser pulse with a high single pulse energy, which is divided into two beams after passing through the beam splitter 2. One beam of light passes through the optical parametric amplifier 1 3 and is used as pump light; the other beam of light passes through the total reflection mirror 4 11 and enters the optical parametric amplifier 2 12 and is used as disturbance light. The femtosecond laser pulse output by the femtosecond laser 1 passes through the beam splitter 2 and enters the optical parametric amplifier 3, passes through the total reflection mirror 1 4, the electric control displacement stage 5, the chopper 6, the total reflection mirror 2 7, the total reflection mirror 3 8, the Glan prism 1 9, the quarter wave plate 10, and then passes through the dichroic mirror 19 and transmits the light beam as pump light. The femtosecond laser pulse output by the femtosecond laser 1 is reflected by the beam splitter 2 to form a beam of light, which passes through the total reflection mirror 4 11, the optical parametric amplifier 12, the total reflection mirror 5 13, the total reflection mirror 6 14, the total reflection mirror 7 15, the Glan prism 2 16, the quarter-wave plate 2 17, the total reflection mirror 8 18, and then passes through the dichroic mirror 1 19 to merge with the pump light, and then passes through the total reflection mirror 9 20 to enter the optical path of the movable optical path panel A or B, wherein:

[0026] The movable optical path panel A is used to explore the threshold conditions of amplified stimulated emission of solution samples in optical fibers. The solution sample to be tested is adsorbed in the optical fiber crystal and placed between two objective lenses to keep it level with the optical path. The laser can enter the optical fiber crystal that adsorbs the solution sample to be tested, and the length of the optical fiber crystal can also be adjusted. The movable optical path panel B is used to explore the threshold conditions of amplified stimulated emission of thin film samples. The thin film sample is fixed on the sample stage of the base, and strip light is irradiated on the sample surface, and the signal is collected on the side of the sample. An adsorbable magnetic buckle will be fixed on the optical platform, and the bottom of the movable optical path panels A and B also have magnetic buckles, which are attracted to the magnetic buckles placed on the optical platform to fix the movable optical path panels A and B.

[0027] First, if the reflected light enters the optical path of the movable optical path panel A, after passing through the objective lens 1 21, the tubular microcavity 22 such as the optical fiber or the capillary, the objective lens 2 23 and the dichroic mirror 2 24, the disturbance light passes through the dichroic mirror 2 24, and the pump light is reflected. Since the main function of the pump light is to excite the sample, the state before and after the excitation is different, and the absorption of the disturbance light after passing through the sample is different, the pump light is not detected. The transmitted light enters the spectrometer 31, and is connected to the signal input port f of the oscilloscope 34 through the signal output port g of the photomultiplier tube 32, and the strength of the signal can be observed on the display interface of the oscilloscope 34; the signal output port i of the CCD 33 is connected to the signal input port m of the computer 36, and the stimulated emission of the solution sample in the optical fiber can be observed on the computer display screen.

[0028] Secondly, if the reflected light enters the optical path of the movable optical path panel (B), a slender strip light spot can be obtained through the combination of the cylindrical mirror 25 and the concave mirror 26 to vertically irradiate one end of the thin film sample on the sample stage 27. The light coming out from the side of the sample is reflected by the lens 28, the filter 29 and the total reflection mirror 30, and then enters the monochromator 31. The signal output port g of the photomultiplier tube 32 is connected to the signal input port f of the oscilloscope 34, and the strength of the signal can be observed on the display interface of the oscilloscope 34; the signal output port i of the CCD 33 is connected to the signal input port m of the computer 36, and the stimulated emission of the thin film sample can be observed on the computer display screen.

[0029] Experimental parameters

[0030]

[0031] The present invention mainly utilizes a beam of femtosecond laser to excite one side of a solution sample or a thin film sample in an optical fiber, and another beam of femtosecond laser to irradiate the sample in the same direction after a certain delay time, to disturb the sample, so as to explore the threshold conditions and various disturbance factors that can cause the sample to produce amplified stimulated emission. By changing various conditions (such as the frequency of the excitation beam, the power of the excitation light, and the delay conditions of adjusting the two beams of light, etc.), the threshold wavelength, minimum power (laser light intensity), delay time range, etc. that can produce amplified stimulated emission can be explored. At the same time, this system places a detachable polarization device on the path of the two beams of light to convert the laser into circularly polarized light, which can be used to study some potential chiral materials. There are also a variety of amplified stimulated emission research methods that can be implemented by this system. Using this system can more comprehensively and deeply explore the amplified stimulated emission characteristics of various substances.

Claims

1. A transient spectroscopy system for measuring amplified stimulated emission characteristics, characterized in that: It consists of a pump laser generating and regulating part I, a disturbance laser generating and regulating part II and a test sample excitation and signal collection part III; except for a spectrometer, an oscilloscope, a phase-locked amplifier and a computer, all the pump laser generating and regulating part I, the disturbance laser generating and regulating part II and the test sample excitation and signal collection part III are placed on the same optical platform; the disturbance laser generating and regulating part II is located at the rear right front of the pump laser generating and regulating part I, and half surrounds the pump laser generating and regulating part I; the test sample excitation and signal collection part III is located at the front left of the pump laser generating and regulating part I and the disturbance laser generating and regulating part II, and the beam splitter of the pump laser generating and regulating part I is connected to the full reflection mirror four of the disturbance laser generating and regulating part II through an optical path; the dichroic mirror one of the test sample excitation and signal collection part III is located at a quarter of the pump laser generating and regulating part I. In front of the wave plate one, the dichroic mirror one and the quarter wave plate one are located on the same horizontal center line, and the quarter wave plate one and the dichroic mirror one are connected through an optical path; the dichroic mirror one of the sample to be tested excitation and signal collection part III is located on the left of the total reflection mirror eight in the disturbance laser generation and adjustment part II, and the dichroic mirror one and the total reflection mirror eight are located on the same horizontal center line, and the total reflection mirror eight and the dichroic mirror one are connected through an optical path; the electric control displacement stage signal output port b and the chopper signal output port a of the pump laser generation and adjustment part I are respectively connected to the computer signal input port o and the phase-locked amplifier signal input port k of the sample to be tested excitation and signal collection part III through cables, and the femtosecond laser signal output port c of the pump laser generation and adjustment part I are respectively connected to the oscilloscope signal input port d and the CCD signal input port h of the sample to be tested excitation and signal collection part III through cables; The pump laser generation and adjustment part I is composed of a femtosecond laser, a beam splitter, an optical parametric amplifier 1, a total reflection mirror 1, an electrically controlled displacement stage, a chopper, a total reflection mirror 2, a total reflection mirror 3, a Glan prism 1 and a quarter wave plate 1, wherein the electrically controlled displacement stage is provided with an output port b, and the chopper is provided with an output port a; the femtosecond laser, the beam splitter, the optical parametric amplifier 1 and the total reflection mirror 1 are arranged in sequence from left to right; the electrically controlled displacement stage, the chopper, the total reflection mirror 2 and the total reflection mirror 1 are arranged in sequence from front to back; the total reflection mirror 3, the Glan prism 1 and the quarter wave plate 1 are arranged in sequence from back to front, and the total reflection mirror 3, the Glan prism 1 and the quarter wave plate 1 are located on the same horizontal center line; The disturbance laser generation and adjustment part II is composed of a total reflection mirror 4, an optical parametric amplifier 2, a total reflection mirror 5, a total reflection mirror 6, a total reflection mirror 7, a Glan prism 2, a quarter wave plate 2 and a total reflection mirror 8, wherein the total reflection mirror 4, the optical parametric amplifier 2 and the total reflection mirror 5 are arranged from left to right, and the total reflection mirror 4, the optical parametric amplifier 2 and the total reflection mirror 5 are located on the same horizontal center line; the total reflection mirror 6 is located in front of the total reflection mirror 5, and the total reflection mirror 7 is located on the left of the total reflection mirror 6; the total reflection mirror 7, the Glan prism 2, the quarter wave plate 2 and the total reflection mirror 8 are arranged from front to back, and the total reflection mirror 7, the Glan prism 2, the quarter wave plate 2 and the total reflection mirror 8 are located on the same horizontal center line; The sample excitation and signal collection part III is composed of a dichroic mirror 1, a total reflection mirror 9, a movable optical path panel A and a movable optical path panel B, a spectrometer, an oscilloscope, a phase-locked amplifier and a computer, wherein the total reflection mirror 9 is located in front of the dichroic mirror 1 and is located on the same horizontal center line; the spectrometer includes a photomultiplier tube and a CCD; the photomultiplier tube is provided with a signal output port q and a signal output port g; the CCD is provided with a signal input port h and a signal output port i; the oscilloscope is provided with a signal input port d, a signal output port e and a signal input port f; the phase-locked amplifier The device is provided with a signal input port j, a signal output port l, and a signal input port k; the computer is provided with a signal input port m, a signal input port n, a signal input port o, and a signal input port p; the photomultiplier tube signal output port q is connected to the lock-in amplifier signal input port j; the photomultiplier tube signal output port g is connected to the oscilloscope signal input port f; the CCD signal output port i is connected to the computer signal input port m; the oscilloscope signal output port e is connected to the computer signal input port n; the lock-in amplifier signal output port l is connected to the computer signal input port p; The movable optical path panel A is composed of an objective lens 1, a tubular microcavity of an optical fiber or a capillary, an objective lens 2 and a dichroic mirror 2, wherein the objective lens 1, the tubular microcavity of an optical fiber or a capillary, the objective lens 2 and the dichroic mirror 2 are arranged from right to left, and the objective lens 1, the tubular microcavity of an optical fiber or a capillary, the objective lens 2 and the dichroic mirror 2 are located on the same horizontal center line; The movable optical path panel B is composed of a cylindrical mirror, a concave mirror, a sample stage, a lens, a filter and a total reflector ten, wherein the cylindrical mirror, the concave mirror and the sample stage are arranged from right to left, and the cylindrical mirror and the concave mirror are arranged perpendicular to the sample stage; the sample stage, the lens, the filter and the total reflector ten are arranged from back to front, and the sample stage, the lens, the filter and the total reflector ten are located on the same horizontal center line; The femtosecond laser outputs a single pulse energy femtosecond laser pulse, which is divided into two beams after passing through a beam splitter, one of which is used as a pump light after passing through an optical parametric amplifier 1; the other beam passes through a total reflection mirror 4 and enters an optical parametric amplifier 2 and is used as a disturbance light; the femtosecond laser pulse output by the femtosecond laser passes through the beam splitter and enters the optical parametric amplifier, passes through a total reflection mirror 1, an electric-controlled displacement stage, a chopper, a total reflection mirror 2, a total reflection mirror 3, a Glan prism 1, and a quarter-wave plate 1, and then the light beam transmitted through a dichroic mirror 1 is used as a pump light, and the femtosecond laser pulse output by the femtosecond laser is reflected by the beam splitter to produce a beam of light, passes through a total reflection mirror 4, an optical parametric amplifier, a total reflection mirror 5, a total reflection mirror 6, a total reflection mirror 7, a Glan prism 2, a quarter-wave plate 2, and a total reflection mirror 8, enters a dichroic mirror 1 and merges with the pump light, and passes through a total reflection mirror 9 together into the optical path of a movable optical path panel A or B, wherein: The movable optical path panel A is used to explore the threshold conditions of amplified stimulated emission of solution samples in optical fibers. The solution sample to be tested is adsorbed in the tubular microcavity of the optical fiber or capillary and placed between two objective lenses to keep it level with the optical path. The laser enters the tubular microcavity of the optical fiber or capillary that adsorbs the solution sample to be tested, and the length of the tubular microcavity of the optical fiber or capillary can be adjusted; the movable optical path panel B is used to explore the threshold conditions of amplified stimulated emission of thin film samples. The thin film sample is fixed on the sample stage of the base, and strip light is irradiated on the sample surface. Signals are collected on the side of the sample. An adsorbable magnetic buckle is fixed on the optical platform. The bottom of the movable optical path panels A and B also has a magnetic buckle, which is attracted to the magnetic buckle placed on the optical platform to fix the movable optical path panels A and B. First, if the reflected light enters the optical path of the movable optical path panel A, it passes through the objective lens 1, the tubular microcavity of the optical fiber or capillary, the objective lens 2 and the dichroic mirror 2, and the disturbance light passes through the dichroic mirror 2, and the pump light is reflected. Because the pump light acts to excite the sample, the states before and after the excitation are different, and the absorption of the disturbance light after passing through the sample is different, so the pump light is not detected, and the transmitted light enters the spectrometer, and is connected to the oscilloscope signal input port f through the photomultiplier tube signal output port g, and the signal strength is observed on the display interface of the oscilloscope; it is connected to the computer signal input port m through the CCD signal output port i, and the stimulated emission of the solution sample in the optical fiber is observed on the computer display screen; Secondly, if the reflected light enters the optical path of the movable optical path panel B, a slender strip light spot is obtained through the combination of the cylindrical mirror and the concave mirror, and vertically irradiates one end of the thin film sample on the sample stage. The light coming out from the side of the sample is reflected by the lens, the filter and the total reflection mirror ten, and then enters the spectrometer. It is connected to the oscilloscope signal input port f through the photomultiplier tube signal output port g, and the signal strength is observed on the display interface of the oscilloscope; it is connected to the computer signal input port m through the CCD signal output port i, and the stimulated emission of the thin film sample is observed on the computer display screen.

2. The instantaneous spectroscopy system for measuring amplified stimulated emission characteristics according to claim 1, characterized in that: The beam splitter is a 9:1 beam splitter, which makes the ratio of the intensity of transmitted and reflected light be 9:1.

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