A wide-spectrum defect diagnosis system based on multi-pulse timing control
By using a multi-pulse timing-controlled broadband defect diagnostic system, combined with pump light, dump light, and push light, ultra-high spatiotemporal resolution detection of defect states in semiconductor materials was achieved. This solves the problem of insufficient defect state resolution in existing technologies and improves the design and manufacturing capabilities of optoelectronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2026-03-10
- Publication Date
- 2026-07-07
Smart Images
Figure CN121830683B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of ultrafast laser spectroscopy technology, specifically relating to a broadband defect diagnosis system based on multi-pulse timing modulation, and particularly to a dynamic diagnosis system for semiconductor material defects based on multi-pulse timing modulation and broadband detection. Background Technology
[0002] In the research and manufacturing of semiconductor optoelectronic devices, the existence of surface defect states is one of the core bottlenecks restricting the improvement of material performance. These defect states, acting as non-radiative recombination centers, not only accelerate the wasteful dissipation of charge carriers but also significantly reduce the luminous efficiency, stability, and lifespan of optoelectronic devices. Current mainstream defect characterization techniques mainly rely on chemical analysis or static structural observation, such as identifying surface chemical bonding states through X-ray photoelectron spectroscopy or capturing local distortions in crystal structures using transmission electron microscopy. However, these methods only provide static chemical or morphological information about defects and lack effective analysis of the dynamic interactions between defect states and material band structures, energy distribution, and the competition mechanism of charge carrier capture-escape. While traditional transient absorption spectroscopy can track the macroscopic relaxation behavior of charge carriers, it struggles to distinguish the dynamic differences between free charge carriers and defect-bound charge carriers, leaving the depth, density, and impact on device performance of defect states in a "black box" state for a long time.
[0003] In recent years, with the widespread application of soft lattice semiconductors such as quantum dots and perovskites in displays, photovoltaics, and sensors, the demand for accurate diagnosis of defect states has become increasingly urgent. Especially in quantum dot light-emitting diodes (LEDs), surface defect states directly determine carrier injection efficiency and nonradiative recombination rate. However, existing technologies cannot provide quantitative data on the energy distribution of defect states, making interface engineering optimization strategies largely reliant on empirical trial and error, resulting in low efficiency and a lack of universality. For example, although surface passivation and core-shell coating can partially suppress defect states, the lack of clarity regarding their physical properties makes it difficult to specifically control the defect depth and distribution density, leading to a significant ceiling on device performance improvement. Summary of the Invention
[0004] The purpose of this invention is to provide a broadband defect diagnostic system based on multi-pulse timing modulation. This diagnostic system consists of a pump-excitation photonics system, a probe light generation and detection subsystem, and a dump / push light modulation subsystem. It can achieve ultra-high spatiotemporal resolution detection of defect states in semiconductor materials such as perovskite and quantum dots, and accurately analyze the entire process of defect capture, vibrational coupling, and non-radiative recombination.
[0005] The broadband defect diagnostic system based on multi-pulse timing modulation described in this invention is an advanced semiconductor defect diagnostic system that focuses on the combined application of multi-pulse timing modulation and broadband detection technologies. This system uses an adjustable pump source to excite charge carriers in semiconductor materials, and then utilizes dump / push light technology for selective manipulation, precisely influencing and controlling defect states. Furthermore, the system can simultaneously analyze electronic transitions and charge carrier transport processes, enabling ultra-high spatiotemporal resolution dynamic detection of defect states in semiconductor materials. This system not only supports multi-pulse coordinated timing control but also possesses broadband spectral response capabilities and can perform vibrational-electronic coupling modeling analysis. Therefore, it provides a precise diagnostic tool for the field of optoelectronic device defect engineering, helping to deeply understand the impact of defects on device performance and thus optimize the design and manufacturing processes of optoelectronic devices.
[0006] This invention discloses a spectral diagnostic system based on ultrafast laser synergistic modulation, which overcomes the limitations of existing technologies through the temporal coupling and dynamic perturbation of multi-band laser pulses. The system uses ultraviolet light to simulate the operating conditions of carriers being trapped in defect states, and infrared light to selectively re-excite the bound carriers. Combined with high-precision time delay control and multi-channel synchronous signal acquisition, it achieves dynamic analysis of the energy depth and distribution density of defect states. Specifically, after the pump light excites carriers to the conduction band, ultraviolet light selectively unloads them into defect states, simulating the carrier trapping process in actual device operation. Infrared light acts as a dynamic perturbation source, re-exciting carriers from defect states at different depths to the conduction band through photon energy scanning. Combined with the synergistic analysis of transient absorption signals and full-spectrum responses, the depth distribution and density characteristics of defect states are quantified. This method can not only capture the femtosecond-level transient behavior of carriers escaping from defect states in real time, but also adapt to the band structure differences of different semiconductor systems through wide spectral coverage, providing a universal solution for defect state research in materials such as perovskites and quantum dots.
[0007] The present invention discloses a broadband defect diagnosis system based on multi-pulse timing modulation, comprising a wavelength-tunable pulsed laser, a pump-excitation photonics system, a probe light generation and detection subsystem, and a dump / push light modulation subsystem. The pump-excitation photonics system consists of a first output port of the pulsed laser, a first mirror, a second mirror, a first achromatic lens, a first chopper, a second achromatic lens, a third mirror, a fourth mirror, a third achromatic lens, and a sample. The probe light generation and detection subsystem consists of a second output port of the pulsed laser, a sixth mirror, a seventh mirror, an eighth mirror, a ninth mirror, a tenth mirror, an eleventh mirror, a twelfth mirror, a thirteenth mirror, a fourteenth mirror, a fifteenth mirror, and a third... The system consists of a backlight reflector, a fourth backlight reflector, an eighteenth reflector, a nineteenth reflector, a BBO crystal (β-phase barium borate), a first beam splitter, a second beam splitter, a first sapphire crystal, a second sapphire crystal, a second displacement stage, a fourth achromatic lens, a fifth achromatic lens, a monochromator, a photomultiplier tube, a lock-in amplifier, a sixth lens, a spectrometer, a computer, and a sample. The Dump / push light control subsystem consists of the third output port of the pulsed laser, the twentieth reflector, the twenty-first reflector, the twenty-second reflector, the twenty-third reflector, the twenty-fourth reflector, the twenty-fifth reflector, the fifth reflector, a first displacement stage, a first achromatic lens, a first chopper, a second achromatic lens, a third achromatic lens, and a sample.
[0008] The samples included perovskite, quantum dots, and other semiconductor materials.
[0009] The pump light, dump light, push light, and probe light all come from a wavelength-tunable pulsed laser.
[0010] In the pump photonics system, the first achromatic lens, the first chopper, and the second achromatic lens are arranged along the optical axis. The first and second achromatic lenses are a lens group with matched focal lengths (the distance between the two lenses is the sum of their focal lengths). The first chopper is a frequency-tunable pulse modulation component located between the first and second achromatic lenses, which precisely adjusts the time distribution of the pump light output from the first output port.
[0011] First, a wavelength-tunable pulsed laser emits pump light with a wavelength of 300~1030nm and a power of 200mW~2W through the first output port. The pump light is spatially collimated by the first and second reflecting mirrors to form a collimated beam. The collimated beam is then converted into parallel light by the first and second achromatic lenses. The first chopper modulates the pulse time sequence of the beam with an adjustable frequency of 1Hz~10kHz to precisely control the timing relationship between the pump light and the probe light. After secondary reflection by the third and fourth reflecting mirrors, the modulated parallel light is finally focused onto the sample by the third achromatic lens to form an excitation spot with a diameter of about 50μm, which excites the charge carriers in the sample to the conduction band, laying the foundation for defect state detection.
[0012] In the probe light generation and detection subsystem, the lock-in amplifier is used for high signal-to-noise ratio signal extraction, and the spectrometer enables wide-spectrum detection.
[0013] First, the 1030nm probe light output from the second laser output port is collimated by the sixth, seventh, and eighth reflecting mirrors before being incident on the BBO crystal for phase matching and frequency doubling, generating a 515nm second harmonic, thus forming a dual-band probe light of 515nm and 1030nm. The first beam splitter separates the dual-band probe light into two paths: the 515nm probe light is incident on the second sapphire crystal via the thirteenth and fourteenth reflecting mirrors, generating a supercontinuum probe light of 280~515nm; the 1030nm probe light is incident on the first sapphire crystal via the ninth reflecting mirror, generating a supercontinuum probe light of 515~1030nm. The 280~515nm supercontinuum probe light passes through the fifteenth reflecting mirror, and the 515~1030nm supercontinuum probe light passes through the tenth reflecting mirror and... The eleventh mirror and the pump light are ultimately combined in a mutually perpendicular direction at the twelfth mirror. The light is then transmitted from the twelfth mirror to the third and fourth return mirrors on the second displacement stage. A 0-10 ns time delay between the probe and pump light is adjusted with a 0.1 μm step precision, thus accurately matching the detection timing with the carrier dynamics. The delayed probe light is reflected by the eighteenth mirror, focused by the fourth achromatic lens, and then incident on the sample. The probe light passing through the sample is split into two paths by the nineteenth mirror and the second beam splitter: one path is coupled to the monochromator through the fifth achromatic lens, where a specific wavelength (wavelength range 200-2000 nm) is selected. This signal is then converted into an electrical signal by a photomultiplier tube and fed into a lock-in amplifier to extract a high signal-to-noise ratio (SNR) signal (system sensitivity 10). -4One path is the time-resolved absorption signal; the other path is coupled to the spectrometer via the sixth achromatic lens to acquire the full-band transient absorption spectrum; the two output signals of the lock-in amplifier and the spectrometer are synchronously connected to the computer through the data interface to ensure real-time acquisition and analysis of the signal; then the spectral dynamics processing software in the computer is used to correlate the time-spectral dimension data in real time to construct the defect state dynamics map.
[0014] The Dump / push optical control subsystem consists of a pulsed laser, where the twentieth and twentieth mirrors form an ultraviolet light reflector group, and the twentieth and twentieth mirrors form an infrared light reflector group.
[0015] The ultraviolet pulse light (UV, 200~400nm) output from the third output port of the laser, which serves as the drain light, or the infrared pulse light (IR, 1.5~5μm) which serves as the push light, is collimated by the ultraviolet light reflecting mirror group or the infrared light reflecting mirror group, and then incident on the first and second return light reflecting mirrors in the first displacement stage. The time delay between the pulse light and the pump light is adjusted by 0~1μs through the precise control of the first displacement stage. The adjusted pulse light passes through the twenty-fourth and twenty-fifth reflecting mirrors, and then through the first and second achromatic lenses to be adjusted into parallel light. Finally, the fifth reflecting mirror and the third achromatic lens achieve coaxial focusing with the pump / probe light onto the sample.
[0016] UV light, acting as a dump (beam absorption) light, achieves excited-state quenching through electronic state transitions. After pumping carriers, it selectively removes free carriers from the conduction band, retaining only carriers trapped in defect states and reducing background signal interference. IR light, acting as a push (carrier excitation) light, drives energy states through vibrational mode resonance. It scans defect states at different depths with tunable photon energy, re-exciting bound carriers back to the conduction band. In the defect state characterization of quantum dots and perovskite materials, by adjusting the dump light energy and time delay, selective retention and separation of defect states at different depths can be achieved (e.g., carriers in shallow defect states can be preferentially removed by dump light of specific energies). Combining the scanning push light energy with differential signal analysis (comparing the signal difference with and without dump / push effects), not only can the energy level difference between defect states and the conduction band be accurately measured, but the defect state density distribution can also be quantified through signal amplitude changes, and carrier trapping and recombination dynamics can be analyzed. The method described in this invention significantly enhances the ability to distinguish surface / bulk defect state energy levels, spatial distribution, and carrier transport paths through dual temporal and energy regulation, providing key physical information for material interface engineering and defect control.
[0017] Pump, probe, dump, and push beams are coaxially focused onto the sample through a third and a fourth achromatic lens, ensuring precise spatiotemporal matching of the multiple beams. The pump beam excites charge carriers in the sample to the conduction band, the dump beam selectively removes free charge carriers while retaining defect-state charge carriers, the push beam re-excites defect-state charge carriers back to the conduction band, and the dual-band probe beam captures the transient absorption signal of the sample. Combined with temporal modulation and broadband spectral analysis, the depth and density of defect states are quantitatively analyzed.
[0018] The core innovation of this invention lies in combining dynamic perturbation with high-sensitivity detection, achieving for the first time a multi-dimensional analysis of the physical properties of defect states. Through the coordinated design of a beam splitter and a spectrometer, the system described in this invention can simultaneously acquire transient absorption kinetic curves and full-spectrum response data. Combined with high signal-to-noise ratio signal extraction using a lock-in amplifier, the detection sensitivity for low-concentration defect states is significantly improved. Furthermore, the independent optical path design for ultraviolet and infrared light, along with a coaxial focusing mechanism, ensures precise spatiotemporal matching of multi-band lasers, avoiding data distortion caused by optical path crosstalk in traditional technologies. This technological breakthrough not only provides crucial theoretical support for the interface engineering optimization of semiconductor materials (e.g., guiding surface ligand design or passivation layer thickness control through defect depth data), but also directly relates to device performance parameters (such as external quantum efficiency and carrier mobility), driving a paradigm shift in optoelectronic devices from empirical optimization to rational design. At the application level, this technology is not only applicable to optoelectronic devices such as quantum dot light-emitting diodes and perovskite solar cells, but can also be extended to fields such as photocatalysis and energy storage, providing a novel research tool for revealing the role of defect states in processes such as charge separation and interfacial reactions, possessing broad scientific value and industrialization potential. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the broadband defect diagnosis system based on multi-pulse timing modulation described in this invention. Detailed Implementation
[0020] Example 1
[0021] Figure 1In the middle, the first achromatic lens (4) is Sorebo AC127-050-A-ML with a focal length of 5cm; the first chopper (5) is Beijing Zhuoli Hanguang Model-300CD; the second achromatic lens (6) is Sorebo AC127-075-A-ML with a focal length of 7.5cm; the third achromatic lens (9) is Sorebo AC127-050-A-ML with a focal length of 5cm; BBO crystal (2 4) is a BBO phase-matched frequency-doubling crystal from Kangguan Optoelectronics; the first beam splitter (25) is an Everix from Edmund Optics; the ninth reflector (26) is a GCC-10222 concave reflector from Daheng Optoelectronics; the first sapphire crystal (27) is an SAP from Jingtai Crystal; the tenth reflector (28) is a GCC-10222 concave reflector from Daheng Optoelectronics; the fourteenth reflector (32) is a GCC-10222 concave reflector from Daheng Optoelectronics. The mirrors are as follows: the fifteenth mirror (34) is a GCC-10222 concave mirror from Daheng Optoelectronics; the fourth achromatic lens (39) is an AC127-050-A-ML from Sorebo, with a focal length of 5cm; the second beam splitter (42) is an Everix from Edmund Optics; the fifth achromatic lens (43) is an AC127-075-A-ML from Sorebo, with a focal length of 7.5cm; the monochromator (44) is an MS260i from Ivantis; the photomultiplier tube (45) is an R928 from Hamamatsu; the lock-in amplifier (46) is an SR830 from Stanford; the computer (47) is a Precision7920Tower from Dell; the sixth achromatic lens (48) is an AC127-050-A-ML from Sorebo, with a focal length of 5cm; the spectrometer (49) is a QE65Pro from Ocean Optics; and the wavelength-tunable pulsed laser (1) is a Light The conversion of the PHAROS. The first reflector (2), the second reflector (3), the third reflector (7), the fourth reflector (8), the fifth reflector (20), the sixth reflector (21), the seventh reflector (22), the eighth reflector (23), the eleventh reflector (29), the twelfth reflector (30), the thirteenth reflector (31), the eighteenth reflector (38), the nineteenth reflector (41), the twentieth reflector (11), the twenty-first reflector (12), the twenty-second reflector (13), the twenty-third reflector (14), the twenty-fourth reflector (18), and the twenty-fifth reflector (19) are GMH12-100-AG plane reflectors of Hengyang Optics; the first backlight reflector (16) and the second backlight reflector (17) are HR1015-F01 of Sorebo; the third backlight reflector (35) and the fourth backlight reflector (36) are HR1015-M01 of Sorebo.
[0022] like Figure 1As shown, the broadband defect diagnosis system based on multi-pulse timing modulation of the present invention consists of three parts: a pump excitation photonics system, a probe light generation and detection subsystem, and a dump / push light modulation subsystem.
[0023] The pump photonic system consists of a first output port (1) of a pulsed laser, a first reflector (2), a second reflector (3), a first achromatic lens (4), a first chopper (5), a second achromatic lens (6), a third reflector (7), a fourth reflector (8), a third achromatic lens (9), and a sample (40). The first achromatic lens (4), the first chopper (5), and the second achromatic lens (6) are arranged on the same optical axis. The first achromatic lens (4) and the second achromatic lens (6) are a lens group with matching focal lengths (the distance between the two lenses is the sum of the focal lengths of the two lenses). The first chopper (5) is a frequency-tunable pulse modulation component located between the first achromatic lens (4) and the second achromatic lens (6), which precisely adjusts the time distribution of the pump light output from the first output port (1).
[0024] First, a wavelength-tunable pulsed laser emits pump light with a wavelength of 300~1030nm and a power of 200mW~2W through the first output port (1). The light passes through the first reflector (2) and the second reflector (3) for spatial collimation adjustment to form a collimated beam. The collimated beam is then converted into parallel light through the first achromatic lens (4) and the second achromatic lens (6). The first chopper (5) modulates the pulse time sequence of the beam with an adjustable frequency of 1Hz~10kHz to precisely control the timing relationship between the pump light and the probe light. After secondary reflection by the third reflector (7) and the fourth reflector (8), the modulated parallel light is finally focused onto the sample (40) through the third achromatic lens (9) to form an excitation spot with a diameter of about 50μm, which excites the charge carriers in the sample (40) to the conduction band, laying the foundation for defect state detection.
[0025] The detection light generation and detection subsystem consists of the second output port (50) of the pulsed laser, the sixth reflector (21), the seventh reflector (22), the eighth reflector (23), the ninth reflector (26), the tenth reflector (28), the eleventh reflector (29), the twelfth reflector (30), the thirteenth reflector (31), the fourteenth reflector (32), the fifteenth reflector (34), the third return reflector (35), the fourth return reflector (36), the eighteenth reflector (38), and the nineteenth reflector (41), BBO. The system consists of a crystal (24), a first beam splitter (25), a second beam splitter (42), a first sapphire crystal (27), a second sapphire crystal (33), a second displacement stage (37), a fourth achromatic lens (39), a fifth achromatic lens (43), a monochromator (44), a photomultiplier tube (45), a lock-in amplifier (46), a sixth lens (48), a spectrometer (49), a computer (47), and a sample (40). The lock-in amplifier (46) is used for high signal-to-noise ratio signal extraction, and the spectrometer (49) realizes wide-spectrum detection.
[0026] First, the 1030nm probe light output from the second output port (50) of the laser is collimated by the sixth mirror (21), the seventh mirror (22) and the eighth mirror (23), and then incident on the BBO crystal (24) to achieve phase matching and frequency doubling, generating a 515nm second harmonic, forming a dual-band probe light of 515nm and 1030nm; the first beam splitter (25) separates the dual-band probe light into two paths: the 515nm probe light passes through the thirteenth mirror (31) and the fourteenth mirror (23). The mirror (32) is incident on the second sapphire crystal (33), generating a supercontinuum probe light of 280~515nm; the 1030nm probe light is incident on the first sapphire crystal (27) via the ninth mirror (26), generating a supercontinuum probe light of 515~1030nm; the 280~515nm supercontinuum probe light passes through the fifteenth mirror (34), and the 515~1030nm supercontinuum probe light passes through the tenth mirror (28) and the eleventh mirror in sequence. (29) Finally, the two beams are spatially combined in mutually perpendicular directions at the twelfth mirror (30); then the beams are transmitted from the twelfth mirror (30) to the third and fourth return mirrors (35) and the fourth return mirror (36) on the second displacement stage (37). The time delay of the probe light and the pump light is adjusted by a step precision of 0.1 μm to achieve precise matching of the detection time and the carrier dynamics process; the delayed probe light is reflected by the eighteenth mirror (38) and then focused by the fourth achromatic lens (39) and incident into the sample (40). The probe light passing through the sample (40) is split into two paths after passing through the nineteenth mirror (41) and the second beam splitter (42): one path is coupled to the monochromator (44) through the fifth achromatic lens (43) to select the light signal of a specific wavelength (wavelength range 200~2000nm), and then converted into an electrical signal by the photomultiplier tube (45) and connected to the lock-in amplifier (46) to extract the high signal-to-noise ratio (the system sensitivity is 10). -4 The time-resolved absorption signal is obtained from the sixth achromatic lens (48) and the other path is coupled to the spectrometer (49) to obtain the full-band transient absorption spectrum. The two output signals of the lock-in amplifier (46) and the spectrometer (49) are synchronously connected to the computer (47) through the data interface to ensure real-time acquisition and analysis of the signal. Then, the spectral dynamics processing software in the computer (47) is used to associate the time-spectral dimension data in real time to construct the defect state dynamics map.
[0027] The Dump / push optical control subsystem consists of the third output port (10) of the pulsed laser, the twentieth mirror (11), the twenty-first mirror (12), the twenty-second mirror (13), the twenty-third mirror (14), the twenty-fourth mirror (18), the twenty-fifth mirror (19), the fifth mirror (20), the first displacement stage (15), the first achromatic lens (4), the first chopper (5), the second achromatic lens (6), the third achromatic lens (9), and the sample (40). Among them, the twentieth mirror (11) and the twenty-first mirror (12) are ultraviolet light reflector groups, and the twenty-second mirror (13) and the twenty-third mirror (14) are infrared light reflector groups.
[0028] The ultraviolet pulse light (UV, 200~400nm) output from the third output port (10) of the laser, which is used as a dump light or an infrared pulse light (IR, 1.5~5μm) as a push light, is collimated by the ultraviolet light reflector group or the infrared light reflector group and then incident on the first return reflector (16) and the second return reflector (17) in the first displacement stage (15). The time delay between the pulse light and the pump light is adjusted by 0~1μs through the precise control of the first displacement stage (15). The pulse light after adjustment passes through the twenty-fourth reflector (18) and the twenty-fifth reflector (19), and then passes through the first achromatic lens (4) and the second achromatic lens (6) to be adjusted into parallel light. Finally, the fifth reflector (20) and the third achromatic lens (9) achieve coaxial focusing with the pump / probe light into the sample (40).
[0029] Calculation of initial total carrier density:
[0030]
[0031] In the formula: d is the initial total carrier density; d is the sample thickness; For pump pulse energy; The pump light wavelength; The sample absorption coefficient; The value represents the sample reflectance.
[0032] The correlation formula between transient absorption and defect state carriers:
[0033]
[0034] In the formula: Transient absorption rate; This represents the absorption cross section for defect-state carriers. To detect optical path length; Let be the carrier density of the defect state at time t.
[0035] Defect state energy level depth quantization:
[0036]
[0037] In the formula: The depth of the defect state energy level; The energy at the bottom of the conduction band; The push light excitation threshold frequency.
[0038] Defect state density calculation:
[0039]
[0040] In the formula: The change in carrier density before and after push photoexcitation; To excite the volume; To improve the efficiency of Dump light removal; This represents the push photoexcitation efficiency. All data in the above formulas can be obtained through measurement and processing.
[0041] In the characterization of defect states in quantum dots and perovskite materials, selective retention and separation of defect states at different depths can be achieved by adjusting the energy and time delay of the dump light (e.g., carriers in shallow defect states can be preferentially removed by dump light of specific energies). By combining scanning push light energy with differential signal analysis (comparing the signal difference with and without dump / push effects), and substituting these into the above formula, the energy level difference between defect states and the conduction band, the defect state density distribution, and the carrier trapping and recombination dynamics can be accurately determined. This method, through dual temporal and energy regulation, significantly enhances the resolution of surface / bulk defect state energy levels, spatial distribution, and carrier transport paths, providing crucial physical information for material interface engineering and defect control.
Claims
1. A broadband defect diagnosis system based on multi-pulse timing modulation, characterized in that: It consists of a wavelength-tunable pulsed laser, a pump-excitation photonic system, a probe light generation and detection subsystem, and a dump / push light control subsystem. The pump-excitation photonic system consists of the first output port (1) of the pulsed laser, the first mirror (2), the second mirror (3), the first achromatic lens (4), the first chopper (5), the second achromatic lens (6), the third mirror (7), the fourth mirror (8), the third achromatic lens (9), and the sample (40). The probe light generation and detection subsystem consists of the second output port (50) of the pulsed laser, the sixth mirror (21), the seventh mirror (22), the eighth mirror (23), the ninth mirror (26), the tenth mirror (28), the eleventh mirror (29), the twelfth mirror (30), the thirteenth mirror (31), the fourteenth mirror (32), the fifteenth mirror (34), the third backlight mirror (35), the fourth backlight mirror (36), the eighteenth mirror (38), and the nineteenth backlight mirror (39). The system consists of a mirror (41), a BBO crystal (24), a first beam splitter (25), a second beam splitter (42), a first sapphire crystal (27), a second sapphire crystal (33), a second shift stage (37), a fourth achromatic lens (39), a fifth achromatic lens (43), a monochromator (44), a photomultiplier tube (45), a lock-in amplifier (46), a sixth achromatic lens (48), a spectrometer (49), a computer (47), and a sample (40); the Dump / push light control subsystem consists of the third output port (10) of the pulsed laser, the twentieth mirror (11), the twenty-first mirror (12), the twenty-second mirror (13), the twenty-third mirror (14), the twenty-fourth mirror (18), the twenty-fifth mirror (19), the fifth mirror (20), a first shift stage (15), a first achromatic lens (4), a first chopper (5), a second achromatic lens (6), a third achromatic lens (9), and a sample (40); Among them, the first achromatic lens (4), the first chopper (5), and the second achromatic lens (6) are arranged on the same optical axis. The first achromatic lens (4) and the second achromatic lens (6) are a lens group with matching focal lengths. The first chopper (5) is a frequency-tunable pulse modulation component located between the first achromatic lens (4) and the second achromatic lens (6), which precisely adjusts the time distribution of the pump light output from the first output port (1). The wavelength-tunable pulsed laser emits pump light with a wavelength of 300~1030nm and a power of 200mW~2W through the first output port (1), which passes through the first reflector (2) and the second achromatic lens (6) in sequence. The second mirror (3) is spatially collimated to form a collimated beam. The collimated beam is then converted into parallel light by the first achromatic lens (4) and the second achromatic lens (6). The first chopper (5) modulates the pulse time sequence of the beam with an adjustable frequency of 1Hz to 10kHz to precisely control the timing relationship between the pump light and the probe light. After secondary reflection by the third mirror (7) and the fourth mirror (8), the modulated parallel light is finally focused onto the sample (40) by the third achromatic lens (9) to form an excitation spot, which excites the charge carriers in the sample (40) to the conduction band, laying the foundation for defect state detection. The 20th reflector (11) and the 21st reflector (12) are ultraviolet light reflector groups, and the 22nd reflector (13) and the 23rd reflector (14) are infrared light reflector groups. The laser's third output port (10) outputs ultraviolet pulse light with a wavelength of 200~400nm or infrared pulse light with a wavelength of 1.5~5μm. After being collimated by the ultraviolet light reflector group or the infrared light reflector group, the light is incident on the first return reflector (16) and the second return reflector (17) in the first displacement stage (15). The time delay adjustment of 0~1μs with the pump light is achieved by the precise control of the first displacement stage (15). The pulse light after adjustment passes through the 24th reflector (18) and the 25th reflector (19), and then passes through the first achromatic lens (4) and the second achromatic lens (6) to be adjusted into parallel light. Finally, the fifth reflector (20) and the third achromatic lens (9) achieve coaxial focusing with the pump / probe light and accurately act on the sample (40).
2. The broadband defect diagnosis system based on multi-pulse timing modulation as described in claim 1, characterized in that: The 1030nm probe light output from the second output port (50) of the laser is collimated by the sixth mirror (21), the seventh mirror (22) and the eighth mirror (23) and then incident on the BBO crystal (24) to achieve phase matching and frequency doubling, generating a 515nm second harmonic, forming a dual-band probe light of 515nm and 1030nm; the first beam splitter (25) separates the dual-band probe light into two paths: the 515nm probe light is incident on the second sapphire crystal (33) through the thirteenth mirror (31) and the fourteenth mirror (32) to generate a supercontinuum probe light of 280~515nm; The 1030nm probe light is incident on the first sapphire crystal (27) through the ninth mirror (26), generating a supercontinuum probe light of 515~1030nm; the 280~515nm supercontinuum probe light passes through the fifteenth mirror (34), and the 515~1030nm supercontinuum probe light passes through the tenth mirror (28) and the eleventh mirror (29) in sequence, and finally the two are spatially combined in mutually perpendicular directions at the twelfth mirror (30); then it is transmitted from the twelfth mirror (30) to the third backlight mirror (35) and the fourth backlight mirror (36) on the second displacement stage (37), and the time delay of the probe light and the pump light is adjusted by a step precision of 0.1μm to achieve precise matching of the detection time and the carrier dynamics process; the delayed probe light is reflected by the eighteenth mirror (38), and then by the fourth elimination After being focused by the chromatic lens (39), the light is incident on the sample (40). The probe light passing through the sample (40) is split into two paths after passing through the nineteenth mirror (41) and the second beam splitter (42): one path is coupled to the monochromator (44) through the fifth achromatic lens (43), and the light signal with a wavelength range of 200~2000nm is selected. Then, it is converted into an electrical signal by the photomultiplier tube (45) and connected to the lock-in amplifier (46) to extract the time-resolved absorption signal with a high signal-to-noise ratio; the other path is coupled to the spectrometer (49) through the sixth achromatic lens (48) to obtain the transient absorption spectrum of the whole band. The two output signals of the lock-in amplifier (46) and the spectrometer (49) are synchronously connected to the computer (47) through the data interface to ensure the real-time acquisition and analysis of the signal. Then, the spectral dynamics processing software in the computer (47) is used to correlate the time-spectral dimension data in real time to construct the defect state dynamics map.
3. A broadband defect diagnosis system based on multi-pulse timing modulation as described in claim 1 or 2, characterized in that: The focal length of the first achromatic lens (4) is 5cm; the focal length of the second achromatic lens (6) is 7.5cm; the focal length of the third achromatic lens (9) is 5cm; the BBO crystal (24) is a BBO phase-matched frequency-doubling crystal; the ninth mirror (26) is a concave mirror; the tenth mirror (28) is a concave mirror; the fourteenth mirror (32) is a concave mirror; the fifteenth mirror (34) is a concave mirror; the focal length of the fourth achromatic lens (39) is 5cm; the focal length of the fifth achromatic lens (43) is 7.5cm; the focal length of the sixth achromatic lens (48) is 5cm; the first achromatic lens (49) is a concave mirror; the first achromatic lens (49) is a concave mirror; the second achromatic lens (6) is a concave mirror; the third achromatic lens (9) is a concave mirror; the fourth achromatic lens (39) is a concave mirror; the fifth achromatic lens (43) is a concave mirror; the sixth achromatic lens (48) is a concave mirror; the fifth achromatic lens (49) is a concave mirror; the sixth achromatic lens (49) is a concave mirror; the fifth achromatic lens (43) is a concave mirror; the sixth achromatic lens (48) is a concave mirror; the third achromatic lens (49) is a concave mirror; the fourth achromatic lens (49) is a concave mirror; the fifth achromatic lens (43) is a concave mirror; the sixth achromatic lens (49) is a concave mirror; the fifth achromatic lens (49) is a concave mirror; the sixth achromatic lens (49) is a concave mirror; the fifth achromatic lens (49) is a concave mirror; the sixth achromatic lens (49 The following mirrors are planar mirrors: mirror (2), mirror (3), mirror (7), mirror (8), mirror (20), mirror (21), mirror (22), mirror (23), mirror (29), mirror (30), mirror (31), mirror (38), mirror (41), mirror (11), mirror (12), mirror (13), mirror (14), mirror (18), mirror (19).