Method and system for evaluating laser damage resistance of cerium-doped barium borosilicate optical glass

Abstract

The present application belongs to the technical field of material performance evaluation, and relates to a method and system for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass evaluates the sample from six dimensions, i.e. the laser damage threshold, the transmittance under a preset wavelength band and a preset working condition, the crack evolution under different shot numbers and different delay times, the damage size evolution, the plasma evolution, and the shock wave evolution, to obtain an evaluation result, and based on the evaluation result, a target sample with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance is screened out. The present application also provides a system for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass, which adopts a pump-probe technology and a time-resolved imaging system with a double-viewing-angle transient capture function to evaluate the plasma dynamics, the shock wave propagation, and the crack evolution process in the laser ablation process of the cerium-doped glass.

Description

Technical Field

[0001] This invention relates to the field of material performance evaluation technology, and in particular to a method and system for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass. Background Technology

[0002] Silicate glass is currently the most commonly used and irreplaceable optical window material in military applications. It is the most widely used optical component in laser systems and optoelectronic detection devices, and has important applications in high-power lasers, deep space probes, optoelectronic detection, and countermeasures. In practical military applications, optical windows are inevitably exposed to radiation environments, such as in space laser optical systems, space telescopes, and laser inertial confinement fusion (LICF) devices. When conventional glass systems are exposed to ionizing radiation, radiation-induced darkening (RID) occurs, which generates color centers, leading to transmission loss and reduced beam quality.

[0003] Current strategies for addressing these problems include transitioning metal ions to glass doping (… , , etc.) or rare earth ions ( , , (etc.) to enhance radiation resistance. Among these ions, cerium (Ce) is considered one of the most effective dopants in optical and photonic devices due to its broad spectral response and bivalent synergistic effect, especially suitable for aluminosilicate and borosilicate glasses.

[0004] It is worth noting that cerium doping can enhance radiation resistance and significantly improve ultraviolet (UV) absorption in the glass matrix. However, this UV absorption can simultaneously lead to laser-induced damage in the glass matrix. and Ions have different ultraviolet absorption mechanisms: Ions pass through Orbital electron transition ( It absorbs ultraviolet light in the 280-350nm range, while The ions then undergo ligand-metal charge transfer (LMCT) transitions between the oxoanion and the Ce cation. Ce doped glass absorbs a wide spectrum of ultraviolet light, and these properties make it a key material for laser applications. Its effectiveness lies in (1) the inherent absorption characteristics in the ultraviolet spectrum, which makes it very suitable as an optical filter for laser protection, detector protection and stray light attenuation; (2) excellent resistance to radiation-induced darkening. However, these properties can also cause damage to the glass substrate.

[0005] When laser systems are exposed to ionizing radiation for extended periods, cerium-doped barium borosilicate optical glass (cerium-doped glass) is often the preferred material. Examples of its applications include NASA's Laser Communications Relay Demonstration (LCRD) project and the optical window of the European Space Agency's (ESA) Probe-V satellite. However, the strong absorption of ultraviolet light by cerium-doped glass may make it more susceptible to laser-induced damage under high-power ultraviolet laser irradiation; ultraviolet laser radiation causes significant heat accumulation on the front surface of cerium-doped glass, leading to surface melting due to a self-focusing effect caused by localized temperature increases and refractive index changes.

[0006] Researching the damage caused by lasers to cerium-doped glasses, revealing its mechanism and evolution, has important practical value for improving the long-term stable operation of laser systems, and is of great scientific significance in fields such as inertial confinement fusion, radiation hardening, and space laser weapons.

[0007] Existing technologies for evaluating the damage to cerium-doped glasses in ionizing radiation environments typically employ methods such as transmittance change detection, chromaticity shift assessment, dose threshold assessment, white light density increment, and density and structure change analysis to assess the material's damage resistance. These evaluation methods all rely on purely numerical assessments, lack direct correlation between results, and fail to provide a visual representation of the damage to Ce-doped glasses. Furthermore, they lack in-situ observation of transient phenomena such as crack evolution, plasma generation, and shock wave propagation, fundamentally hindering the practical application of these materials. Summary of the Invention

[0008] The purpose of this invention is to provide a method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass. The method evaluates samples from six dimensions: laser damage threshold, transmittance under preset wavelength and conditions, crack evolution under different laser strikes and delay times, damage size evolution, plasma evolution, and shock wave evolution. Based on the evaluation results, target samples with the highest laser damage threshold, highest visible light transmittance, and strongest radiation resistance are selected. This invention also provides a laser damage evaluation system for cerium-doped barium borosilicate optical glass, employing pump detection technology and a time-resolved imaging system with dual-view transient capture capabilities to evaluate plasma dynamics, shock wave propagation, and crack evolution during laser ablation of cerium-doped glass.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass, comprising the following steps: Samples of N cerium-doped barium borosilicate optical glasses with different doping concentrations were prepared; The samples were evaluated from six dimensions: laser damage threshold, transmittance under preset wavelength and preset working conditions, crack evolution under different firing times and different delay times, damage size evolution, plasma evolution, and shock wave evolution. Based on the evaluation results, the target samples with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance were selected.

[0010] As one possible approach, firstly, based on the laser damage threshold at the same wavelength and the transmittance under preset bands and preset working conditions, samples to be evaluated are selected from N samples. Then, the crack evolution, damage size evolution, plasma evolution, and shock wave evolution of the sample to be evaluated are carried out under different number of shocks and different delay times to obtain the target sample and its corresponding evaluation results.

[0011] As one possible approach, the laser damage threshold of the sample to be evaluated is the highest, and the transmittance under the preset wavelength and preset operating conditions is greater than or equal to the transmittance threshold.

[0012] As one possible approach, the evaluation of crack evolution under different bursts and different delay times includes the following steps: Obtain a set of damage images of the sample to be evaluated. The set of damage images includes the initial transient damage image of the side, the initial and final transient damage image of the side, the initial transient damage image of the front surface, the initial and final transient damage image of the front surface, and the transient damage image of the side, the final damage image of the side, the transient damage image of the front surface, and the final damage image of the front surface at different times and delay times after the initial damage. The initial damage region and the time of its occurrence are determined based on the initial transient damage image of the side surface, the initial transient damage image of the side surface, the initial transient damage image of the front surface, and the initial transient damage image of the front surface. The initial damage region includes the core damage region and the initial radial crack. Based on the transient damage images of the front surface, the final damage images of the front surface, the transient damage images of the side surface, and the final damage images of the side surface under different occurrences and delay times after the initial damage, the size changes of the core damage region, the size changes of the initial radial crack, the propagation path of the initial radial crack, as well as the size changes of the newly added radial crack and the propagation path of the newly added radial crack are dynamically deduced.

[0013] As one possible implementation, the evaluation of damage size evolution under different bursts and different delay times includes: The maximum radial dimension D and maximum damage depth H of the damage pit are obtained from the final damage images of the front surface and the side surface at each shot and at each delay time. The ratio between the maximum damage depth H and the maximum radial dimension D is further calculated. Based on this, the changes of the maximum radial dimension D, the maximum damage depth H, and the ratio between the maximum damage depth H and the maximum radial dimension D are dynamically deduced.

[0014] As one possible implementation, the evaluation of damage size evolution under different bursts and different delay times also includes: The area of ​​the core damage region is obtained from the final state damage image of the front surface at each shot and each delay time. and the total area of ​​the damage pit And further calculate the area ratio Based on this, the area of ​​the core damage region is dynamically estimated. Total area of ​​the damage pit Area ratio The changes.

[0015] As one possible approach, plasma evolution analysis specifically includes: A set of transient damage images of the side at different delay times after a specific number of shots was obtained, where the specific number of shots refers to the first time plasma appears; The start and end points of the plasma appearance delay time were determined based on the set of lateral transient damage images; Within the range of the start and end points, the plasma intensity change is determined and divided into different stages, including the plasma initiation stage, the plasma enhancement stage, and the plasma decay stage; The radiation resistance of the sample to plasma is evaluated based on the peak intensity and duration of the plasma enhancement phase.

[0016] As one possible implementation method, shock wave evolution analysis specifically includes: Determine the occurrence and delay time of the first occurrence of the shock wave, and further mark the initial shock wave and the secondary shock waves surrounded by the initial shock wave; Analyze the propagation paths of the initial shock wave and the secondary shock wave as the delay time increases; The time for the secondary shock wave to completely dissipate is obtained, and the radiation resistance of the sample to the shock wave is evaluated based on the complete dissipation time. Calculate the relationship between the propagation distance of the initial shock wave and the number of waves, as well as the relationship between the propagation distance and the delay time. The propagation distance is the vertical distance from the peak of the initial shock wave to the front surface of the target sample. The radiation resistance of the sample to shock waves is evaluated based on the transmission distance.

[0017] In a second aspect, the present invention provides a laser damage evaluation system for cerium-doped barium borosilicate optical glass, comprising: a pump-probe shadow imaging module and a laser damage evaluation module; Among them, the pump-probe shadow imaging module is used to acquire the laser damage threshold, transmittance under preset band and preset working conditions of N cerium-doped barium borosilicate optical glass samples with different doping concentrations, as well as the damage image set of the target sample. The damage image set consists of the initial transient damage image of the side, the initial and final transient damage image of the side, the initial transient damage image of the front surface, the initial and final transient damage image of the front surface, and the transient damage image of the front surface, the final damage image of the front surface, the transient damage image of the side, and the final damage image of the side after different number of shots and delay times. The laser damage resistance evaluation module evaluates samples from six dimensions: laser damage threshold, transmittance under preset wavelength and preset working conditions, crack evolution under different firing times and different delay times, damage size evolution, plasma evolution, and shock wave evolution. Based on the evaluation results, the target sample with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance is selected.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: Traditional methods focus only on the final damage state and fail to reveal the spatiotemporal patterns of damage evolution. This invention proposes a method for constructing a multi-dimensional dynamic evaluation system. By tracking the changes in damage morphology under different shock waves over time and combining this with transient characteristic analysis of plasma and shock waves, a comprehensive performance evaluation model is established. This method overcomes the limitations of purely numerical assessment, enabling in-situ visual monitoring of the damage process and a quantitative description of the damage dynamics. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 A flowchart of a laser damage evaluation method for cerium-doped barium borosilicate optical glass provided in an embodiment of the present invention; Figure 2 A schematic diagram of a time-resolved pump-probe shadow imaging system provided in an embodiment of the present invention; Figure 3 The 355nm laser damage threshold of the sample in this embodiment of the invention was tested using the 1-on-1 method; Figure 4 The 355nm laser damage threshold of the sample in the embodiment of the present invention and A graph showing the relationship between doping concentration; Figure 5These are transient and final images of the G2 sample from the side (SV) and front (TV) at different firing times and delay times in this embodiment of the invention. Figure 6 In this embodiment of the invention, the G2 sample was tested at a pump laser energy density of 14.8. The relationship between the maximum radial dimension D of the damage pit, the damage depth H, and the diameter-to-depth ratio D / H and the number of irradiations is shown in the figure. Figure 7 In this embodiment of the invention, the G2 sample was tested at a pump laser energy density of 14.8. At that time, the area of ​​the core damage region Total area of ​​damage pits and area ratio Relationship between irradiation frequency and number of exposures; Figure 8 This is a time series diagram of the damage transient process of sample G2 under different irradiation pulse numbers in an embodiment of the present invention; Figure 9 These are transient damage images of the G2 sample after 5 pump laser irradiations at different delay times for different damage events, as shown in this embodiment of the invention. Figure 10 This is the final state image of sample G2 in the transient image in this embodiment of the invention; Figure 11 This is a graph showing the relationship between the shock wave transmission distance and the number of irradiations for the G2 sample under different delay times in an embodiment of the present invention. Detailed Implementation

[0020] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0021] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0022] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0023] See Figure 1 In a first aspect, embodiments of the present invention provide a method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass, comprising the following steps: S10. Prepare N cerium-doped barium borosilicate optical glass samples with different doping concentrations; S20. The samples were evaluated from six dimensions: laser damage threshold, transmittance under preset wavelength and preset working conditions, crack evolution under different firing times and different delay times, damage size evolution, plasma evolution, and shock wave evolution, to obtain the evaluation results. S30. Based on the evaluation results, target samples with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance were selected.

[0024] Among them, the cerium-doped barium borosilicate optical glass sample can be prepared by high-temperature melting method. As an example, the specific process of the sample is as follows: by As a matrix, different concentrations of (e.g., x = 0 mol%, 0.25 mol%, 0.5 mol%, 0.75 mol%, 1 mol%), combined with As a reducing agent to prevent Oxidation. After the raw materials are mixed and ground, they are melted in an alumina crucible at 1200℃ to 1500℃, quenched and shaped, and then annealed at 650℃ for 20 hours to relieve stress. Finally, they are polished to the design size.

[0025] The laser damage threshold refers to the maximum laser power that a medium can withstand per unit area when the high concentration of laser energy causes local deformation or even complete damage to the interior or surface of the medium. Specifically, it can be achieved by combining a 1-on-1 test method with damage morphology observation, and is used to measure the material's ability to resist laser thermomechanical damage.

[0026] Transmittance refers to the phenomenon of incident light exiting an object after refraction. It is usually characterized by the ratio of the transmitted light flux to the incident light flux. Specifically, the transmittance can be measured in a preset wavelength range using an ultraviolet-visible spectrophotometer. Among them, crack evolution and damage size evolution refer to the evolution of damage morphology under different laser firing times and delays recorded by high-speed microscopy imaging. Crack evolution analysis involves the changes in the geometric features of the damaged area, and specifically, a high-speed microscopic imaging system can be used to record the crack propagation path.

[0027] Among them, plasma evolution and shock wave evolution refer to capturing the propagation characteristics of plasma plumes and shock waves using time-resolved spectrometers and shadow imaging technology. Plasma evolution analysis focuses on changes in the luminescence intensity of ionized gas, which can be achieved by simultaneously acquiring plasma radiation signals using a spectrometer and a high-speed camera. Shock wave evolution analysis focuses on the propagation characteristics of stress waves, which can be achieved by capturing the trajectory of the shock wave front using shadow imaging technology.

[0028] Specifically, by preparing sample groups with different cerium doping concentrations, a fundamental correlation between material properties and composition was established. During laser irradiation, a pump-probe shadow imaging system was used to simultaneously acquire transient image sequences of the damaged area. For crack evolution, a crack growth rate model was established by comparing the radial propagation and depth changes of the damage pit under different laser irradiation cycles. Damage size evolution was revealed by calculating the ratio of damage depth to radial size, showing the evolution law of damage morphology. Plasma evolution analysis quantified the material's resistance to ionizing radiation through time integration of spectral intensity. Shock wave evolution was evaluated by measuring the wavefront propagation velocity to assess the material's buffering performance against mechanical stress. Finally, a multi-dimensional data fusion algorithm was used to select the sample with the best performance in the three core indicators of damage threshold, transmittance, and radiation resistance.

[0029] Compared to existing technologies, traditional methods employing a single evaluation system or purely numerical assessment lack direct correlation between evaluation results and do not intuitively represent the damage results of cerium-doped glass. Furthermore, traditional methods only focus on the final damage state and cannot quantify and reveal the spatiotemporal laws of damage evolution. This invention employs a six-dimensional evaluation system, using multi-dimensional quantification (such as laser damage threshold, transmittance, and dynamic damage evolution) to avoid the one-sidedness of single-index evaluation and ensure a comprehensive assessment of material properties. Moreover, the evaluation method of this invention includes dynamic in-situ observation of the material damage process, resulting in intuitive and reliable evaluation results. This ensures a comprehensive assessment of material properties while deepening the in-situ dynamic monitoring of the entire laser damage process, contributing to further improvements in material design.

[0030] Through the above technical solutions, this application solves the technical problem that traditional evaluation methods cannot fully reflect the dynamic damage process. By multi-dimensional dynamic monitoring, the damage resistance of materials under laser irradiation is accurately quantified. Through time-series analysis of damage evolution under different laser irradiation cycles, the interaction mechanism between crack propagation and stress propagation is revealed. By efficiently and effectively screening samples with optimal overall performance, a reliable basis is provided for material selection in high-power laser devices. This method can effectively guide the composition optimization of cerium-doped glasses, improving their service reliability in space laser systems and inertial confinement fusion devices.

[0031] As one possible approach, firstly, based on the laser damage threshold at the same wavelength and the transmittance under preset bands and preset working conditions, samples to be evaluated are selected from N samples. Then, the crack evolution, damage size evolution, plasma evolution, and shock wave evolution of the sample to be evaluated are carried out under different number of shocks and different delay times to obtain the target sample and its corresponding evaluation results.

[0032] The preset band refers to the frequency or wavelength range that is pre-set in the device or system. As an example, the preset band can be the 200-380nm band, the 400-1500nm band, or other required bands.

[0033] Among them, the preset operating conditions refer to the typical working conditions or operating modes of the system or equipment in a pre-set manner. As an example, the preset operating conditions are to set the incident laser with an input wavelength of 355nm.

[0034] Among them, the samples to be evaluated refer to the samples that meet the requirements of the two parameters after being evaluated by laser damage threshold and transmittance tests.

[0035] The term "times" refers to the number of times a laser pulse is repeatedly applied. This can be precisely controlled using a digital delay generator (DG645) to simulate the cumulative effect of continuous laser irradiation in practical applications.

[0036] The delay time refers to the time interval between the pump laser and the probe laser peak. Specifically, it can be achieved by using a high-speed photodetector in conjunction with a delay circuit to capture the transient process of damage development.

[0037] Specifically, this approach combines phased screening with dynamic damage evolution analysis. First, preliminary screening is conducted using laser damage thresholds and transmittance indices to exclude samples with insufficient damage resistance. Then, for the screened samples to be evaluated, multi-pulse irradiation and time-resolved imaging techniques are employed to simultaneously record the temporal evolution data of crack propagation, damage size changes, plasma intensity, and shock wave propagation. For example, in crack evolution analysis, a correlation model between crack propagation rate and material fracture resistance is established by comparing the radial crack length and branch number of the damage pit under different irradiation cycles. In plasma evolution analysis, the material's tolerance to plasma thermal shock is quantified by measuring the decay curve of plasma luminescence intensity with delay time under specific irradiation cycles.

[0038] Compared to existing technologies, traditional methods assess damage resistance solely through static parameters such as transmittance reduction or laser damage threshold. This means traditional methods rely on static numerical values ​​to evaluate the final state of material failure, failing to reflect the dynamic damage process after laser absorption. Specifically, they cannot evaluate the intermediate state changes from laser absorption to damage, thus hindering precise screening. This new approach, by introducing a multi-dimensional dynamic evaluation mechanism, achieves, for the first time, quantitative in-situ observation of crack propagation paths, peak plasma intensity, and shock wave propagation distance. For example, existing technologies cannot distinguish the effects of single irradiation and multi-pulse cumulative effects on damage morphology, while this approach, through damage image sequences from different irradiation cycles, can clearly identify the critical point of damage mode transition under repeated irradiation.

[0039] Through the above technical solution, this application solves the problem that traditional evaluation methods cannot capture the transient damage evolution process, significantly improving the comprehensiveness and accuracy of laser damage resistance performance evaluation. The phased screening mechanism effectively narrows the range of test samples, reducing the data processing complexity of subsequent dynamic analysis. Simultaneously, by combining multi-dimensional dynamic observation data, it can reveal key failure modes of materials at different irradiation stages. For example, it was discovered for the first time that when the delay time exceeds 50 microseconds, there is a strong correlation between the propagation path of the secondary shock wave and the distribution of internal defects in the material, providing direct experimental evidence for optimizing the material preparation process.

[0040] As one possible approach, the laser damage threshold of the sample to be evaluated is the highest, and the transmittance under the preset wavelength and preset operating conditions is greater than or equal to the transmittance threshold.

[0041] Among them, the highest laser damage threshold refers to the maximum energy density that a material surface can withstand without damage, as determined by laser irradiation testing. Specifically, it can be achieved by using single-point laser irradiation combined with optical microscopy to observe the damage morphology. This parameter directly reflects the material's ultimate ability to resist laser thermal effects.

[0042] The transmittance threshold refers to the minimum transmittance value allowed for the material within the target wavelength range, which is set in advance. Specifically, it can be achieved by measuring the transmission spectrum curve of the sample using a spectrophotometer under set temperature and humidity conditions. This indicator is used to ensure the optical performance of the material in a specific working environment.

[0043] Specifically, this application proposes a dual screening criterion of using the highest laser damage threshold and the transmittance reaching a threshold under a preset wavelength and operating condition when selecting samples for evaluation. After initial sample preparation, all samples are first subjected to laser damage threshold testing by gradually increasing the laser energy density until surface damage morphology is observed, and the corresponding threshold data for each sample are recorded. Subsequently, the transmittance data of each sample under simulated operating conditions is measured within the target wavelength range. By performing correlation analysis on the two sets of data, candidate samples that simultaneously meet the criteria of having a damage threshold within the maximum range and transmittance not lower than the set threshold are selected as samples to be tested. This screening mechanism avoids the performance imbalance problem caused by screening based on a single index in traditional methods by establishing a coupled evaluation standard for damage resistance and optical performance.

[0044] Compared to existing technologies, traditional evaluation methods typically rely on a single indicator such as transmittance or laser damage threshold for screening. For example, they may select only the sample with the highest damage threshold while ignoring its light transmittance, or focus only on samples that meet the transmittance standard but have insufficient damage resistance. This approach establishes a dual-parameter screening model that simultaneously controls optical performance indicators while ensuring the material's fundamental damage resistance, thus solving the problem of inaccurate comprehensive material performance evaluation caused by the single evaluation dimension in existing technologies.

[0045] Through the above technical solution, this application effectively overcomes the problem of the disconnect between the evaluation of laser damage resistance and optical transmission performance, and achieves synergistic optimization of material damage resistance and functional properties. This dual screening mechanism can accurately exclude samples with excellent damage resistance but substandard transmittance, while preventing materials with acceptable transmittance but insufficient durability from entering the subsequent evaluation stage, significantly improving the screening efficiency of high-performance materials.

[0046] As one possible approach, the evaluation of crack evolution under different bursts and different delay times includes the following steps: Obtain a set of damage images of the sample to be evaluated. The set of damage images includes the initial transient damage image of the side, the initial and final transient damage image of the side, the initial transient damage image of the front surface, the initial and final transient damage image of the front surface, and the transient damage image of the side, the final damage image of the side, the transient damage image of the front surface, and the final damage image of the front surface at different times and delay times after the initial damage. The initial damage region and the time of its occurrence are determined based on the initial transient damage image of the side surface, the initial transient damage image of the side surface, the initial transient damage image of the front surface, and the initial transient damage image of the front surface. The initial damage region includes the core damage region and the initial radial crack. Based on the transient damage images of the front surface, the final damage images of the front surface, the transient damage images of the side surface, and the final damage images of the side surface under different occurrences and delay times after the initial damage, the size changes of the core damage region, the size changes of the initial radial crack, the propagation path of the initial radial crack, as well as the size changes of the newly added radial crack and the propagation path of the newly added radial crack are dynamically deduced.

[0047] The damage image set refers to a multi-angle image dataset containing images of the side and front surfaces at the initial transient, final, and subsequent delay times. Specifically, a pump-probe shadow imaging system can be used to simultaneously acquire transient and steady-state images of different observation surfaces, and image sequences at different times and delay times can be acquired through time-triggered control. This feature provides complete spatiotemporal data support for the dynamic analysis of crack evolution.

[0048] The initial damage region includes the core damage region and the initial radial crack. Specifically, image processing algorithms can be used to differentiate the initial transient and final images to identify the boundary of the molten region caused by energy deposition and the crack initiation point formed by stress release. This feature establishes a benchmark reference system for subsequent dynamic simulations.

[0049] Dynamic simulation refers to the analysis of damage propagation process based on time-series images. Specifically, image registration and feature tracking algorithms can be used to quantify the changes in damage morphology at different time points into size parameters and path trajectories. This feature enables the visual reconstruction and quantitative description of crack propagation paths.

[0050] Specifically, the pump-probe shadow imaging system captures damage images of the front and side surfaces of the sample with nanosecond-level temporal resolution. The initial transient image records the rapid response process within microseconds after laser irradiation, while the initial and final-state images reflect the stable damage morphology after milliseconds. By comparing the initial transient and final-state images, the geometric features of the core damage region and the initiation location of the initial crack can be extracted. In subsequent experiments, the system acquires transient and final-state images at preset delay times, uses image processing algorithms to extract contours and match features of the damage region, tracks the radial propagation rate of the core damage region, and identifies the generation location and propagation direction of newly formed cracks through a crack bifurcation detection algorithm.

[0051] Compared with existing technologies, traditional methods rely on single parameters such as transmittance changes or laser damage thresholds to assess the degree of damage, failing to capture the dynamic process of crack initiation and propagation. This method, through multi-angle time-series image acquisition and dynamic simulation, achieves for the first time in-situ observation of crack propagation paths during laser damage, revealing the spatiotemporal correlation between the core damage region and crack propagation, and providing multidimensional data support for analyzing the damage resistance mechanism of materials.

[0052] Through the above technical solution, this application solves the problem that the existing technology cannot observe the dynamic evolution of cracks in situ, and realizes the whole process tracking of the expansion of the core damage area, the initial crack extension path and the generation law of new cracks during laser damage, providing a key analytical means for optimizing the laser damage resistance of cerium-doped barium borosilicate glass.

[0053] As one possible implementation, the evaluation of damage size evolution under different bursts and different delay times includes: The maximum radial dimension D and maximum damage depth H of the damage pit are obtained from the final damage images of the front surface and the side surface at each shot and at each delay time. The ratio between the maximum damage depth H and the maximum radial dimension D is further calculated. Based on this, the changes of the maximum radial dimension D, the maximum damage depth H, and the ratio between the maximum damage depth H and the maximum radial dimension D are dynamically deduced.

[0054] Among them, the number of irradiations refers to the complete process of a single laser pulse irradiating a sample. Specifically, a pulse counter can be used to record the number of irradiations, which is used to characterize the effect of laser energy accumulation on damage propagation.

[0055] The delay time refers to the time interval between the end of the laser pulse and the image acquisition. Specifically, a time synchronization controller can be used to adjust the image acquisition sequence to capture the dynamic changes of the damage morphology in the time dimension.

[0056] Among them, the final state damage image of the front surface refers to the optical microscopic image of the front surface damage area reaching a stable state after laser irradiation. Specifically, it can be acquired by a high-resolution CCD camera at a fixed delay time to extract the lateral expansion features of the damage pit.

[0057] Among them, the side final state damage image refers to the cross-sectional microscopic image of the sample side damage area reaching a stable state after laser irradiation. Specifically, it can be obtained by laser confocal microscopy or scanning electron microscopy and is used to quantify the longitudinal penetration depth of the damage pit.

[0058] The maximum radial dimension D refers to the maximum lateral extension of the damage pit projected onto the front surface. Specifically, it can be measured by image processing software to determine the distance between the two furthest points on the edge of the damage area, which is used to characterize the degree of lateral spread of the damage.

[0059] The maximum damage depth H refers to the maximum vertical penetration of the damage pit projected on the side. Specifically, it can be measured by three-dimensional topography reconstruction technology to measure the vertical distance from the bottom of the damage to the front surface, which is used to characterize the longitudinal penetration capability of the damage.

[0060] Specifically, a three-dimensional spatial data model of the damage morphology is established by simultaneously acquiring final-state damage images of the front and side surfaces. The final-state damage image of the front surface is used to extract the lateral expansion parameters of the damage pit, while the final-state damage image of the side surface is used to measure the longitudinal penetration parameters. The ratio of the maximum radial dimension D to the maximum damage depth H is calculated to construct the aspect ratio parameter H / D, which is used to quantify the three-dimensional proportional relationship of the damage morphology. By comparing the variation curves of D, H, and H / D parameters under different firing counts and delay times, the synergistic effect of lateral diffusion and longitudinal penetration during damage propagation can be dynamically analyzed. For example, when the H / D ratio increases with the number of firing counts, it indicates that the damage mode is gradually changing from lateral expansion on the surface to deep penetration, and at this point, the material's anti-penetration performance needs to be evaluated. The implementation of this method relies on the precise synchronization of the image acquisition sequence and the laser irradiation process to ensure the spatiotemporal consistency of the damage morphology data.

[0061] Compared to existing technologies, traditional methods only provide static assessments based on a single dimension of damage area or depth, failing to reveal the three-dimensional spatial evolution of damage propagation. This method, by jointly analyzing damage morphology data from the front and side surfaces, constructs a three-dimensional damage parameter system, achieving a dynamic quantitative description of the damage depth-to-width ratio. Existing technologies do not address the dynamic derivation of damage morphology ratios, while this method, through the H / D ratio variation curve, can intuitively and quantitatively reflect the damage mode transformation characteristics of materials under repeated laser irradiation, providing crucial three-dimensional spatial evolution data support for evaluating damage resistance performance.

[0062] Through the above technical solution, this application solves the technical problem that traditional evaluation methods cannot quantify the dynamic evolution of the three-dimensional morphology of damage, and achieves accurate characterization of the depth-to-radial dimension ratio during damage propagation. This method can dynamically track the synergistic effect of lateral diffusion and longitudinal penetration of damage pits, providing three-dimensional spatial evolution data for evaluating the damage resistance of cerium-doped barium borosilicate optical glass under repeated laser irradiation, effectively supporting the research and optimization design of the material's laser damage resistance mechanism.

[0063] As one possible implementation, the evaluation of damage size evolution under different bursts and different delay times also includes: The area of ​​the core damage region is obtained from the final state damage image of the front surface at each shot and each delay time. and the total area of ​​the damage pit And further calculate the area ratio Based on this, the area of ​​the core damage region is dynamically estimated. Total area of ​​the damage pit Area ratio The changes.

[0064] The term "times" refers to the number of times a laser pulse irradiates the same location. It can be implemented using a laser pulse counter to characterize the cumulative damage effect of materials under repeated laser shocks.

[0065] The delay time refers to the time interval between the laser pulse application and image acquisition, which can be achieved using a time synchronization controller to capture the transient characteristics of damage evolution.

[0066] Among them, the final state damage image of the front surface refers to the microscopic image of the morphology of the front surface when the damaged area reaches a stable state after laser irradiation. Specifically, it can be obtained by using a high-resolution optical microscope or a scanning electron microscope to extract the geometric parameters of the damaged area.

[0067] Among them, the area of ​​the core damage region It refers to the projected area of ​​the melting or phase transformation region at the center of the damage pit. Specifically, it can be calculated by thresholding the damage image using image processing software and then calculating the pixel area. It is used to characterize the area of ​​the material directly affected by the thermal effect.

[0068] Among them, the total area of ​​the damage pit It refers to the overall damage projection area, including the core region and the crack propagation region. Specifically, it can be achieved by using edge detection algorithms combined with morphological processing to reflect the overall range of damage propagation.

[0069] Among them, the area ratio This refers to the ratio of the core area to the total damaged area, which can be specifically calculated using the numerical calculation module. and The division operation is used to quantify the relative stability of the core region during damage propagation.

[0070] Specifically, by acquiring images of the final state of the front surface at different times and delays, image processing techniques are used to extract the boundary contours of the core damage region and the total damage region. For each time point, the area of ​​the core region is calculated. and total damage area The numerical value, and establish the area ratio The curves show how the laser changes over time and with each irradiation. When the laser is repeatedly applied, the core region may melt and re-solidify due to heat accumulation, leading to… It exhibits nonlinear changes; while the total damaged area The area continues to increase as the crack propagates. The decreasing trend of the area ratio can reflect the dynamic relationship between the crack propagation rate and the stability of the core region. For example, in samples with excellent damage resistance, the area ratio only decreases slowly with increasing crack number of strikes, indicating that the core region maintains high stability; while in samples with poor performance, the area ratio decreases rapidly, suggesting that rapid crack propagation leads to a sharp increase in the total damage area.

[0071] Compared with existing technologies, traditional methods only perform static assessments by measuring damage size at a single time point, failing to reveal the evolution of the internal structure of the damaged region. This proposed method, however, achieves, for the first time, quantitative separation of the core damage region from the crack propagation region through dynamic analysis of area ratios across multiple time points and multiple laser shocks. This accurately identifies the dominant damage propagation mode of materials under repeated laser shocks, providing a key criterion for optimizing the material's damage resistance.

[0072] Through the above technical solution, this application solves the problem that existing technologies cannot dynamically assess the changes in the area of ​​the core damage region and the total damage region, and realizes quantitative characterization of the damage morphology evolution of cerium-doped barium borosilicate optical glass during laser damage. By monitoring the trend of the area ratio with the number of laser strikes and the delay time, the contribution of the thermal effect-dominated region and the mechanical crack propagation region in the damage propagation stage of the material can be effectively distinguished, providing multi-dimensional dynamic data support for evaluating the material's resistance to laser damage.

[0073] As one possible approach, plasma evolution analysis specifically includes: A set of transient damage images of the side at different delay times after a specific number of shots was obtained, where the specific number of shots refers to the first time plasma appears; The start and end points of the plasma appearance delay time were determined based on the set of lateral transient damage images; Within the range of the start and end points, the plasma intensity change is determined and divided into different stages, including the plasma initiation stage, the plasma enhancement stage, and the plasma decay stage; The radiation resistance of the sample to plasma is evaluated based on the peak intensity and duration of the plasma enhancement phase.

[0074] Among them, the specific number of laser strikes refers to the number of times the plasma formation is first observed. This can be achieved by using a high-speed camera system to monitor the damage area after each laser strike in real time. This feature can eliminate invalid data interference from the early stage when no plasma was generated.

[0075] The delay time start and end points refer to the time interval from the first appearance of plasma to its complete dissipation. Specifically, it can be calibrated by the start frame and disappearance frame of the light intensity signal change in the image sequence. This feature defines the effective observation window of plasma activity.

[0076] Among them, the plasma intensity change stage division refers to dividing the light intensity signal curve into three segments: initiation, enhancement, and attenuation according to the slope change. Specifically, it can be achieved by using a differential algorithm to detect the inflection point of the light intensity-time curve. This feature can separate the key dynamic processes of plasma development.

[0077] Specifically, when a high-energy laser is applied to the surface of a cerium-doped glass, transient damage images of the side are continuously captured using a pump-probe shadow imaging system. In the first detection of plasma emission, image sequences at different delay times are extracted to precisely pinpoint the start and end times of plasma activity. By analyzing the spatial evolution of the light intensity distribution in the image sequences, a curve of plasma intensity versus time is plotted. This curve is divided into an initial stage, an enhancement stage, and a decay stage. The initial stage reflects the initial threshold of ionization at the material surface, the enhancement stage corresponds to the plasma energy accumulation process, and the decay stage reflects the energy dissipation characteristics. By calculating the maximum light intensity value and its duration during the enhancement stage, a quantitative correlation is established with the material's radiation resistance: the peak intensity characterizes the material's ultimate ability to withstand plasma impact, and the duration reflects the material's tolerance to sustained energy.

[0078] Compared with existing technologies, traditional methods only assess radiation resistance performance through static parameters such as transmittance changes or laser damage threshold, failing to capture transient plasma phenomena generated during laser action. This scheme, through dynamic image sequence analysis, achieves, for the first time, in-situ observation of the entire process of plasma generation, development, and dissipation. In particular, by dividing the process into stages, it reveals the material's response characteristics at different energy stages, providing dynamic data support for the study of radiation resistance mechanisms.

[0079] Through the above technical solution, this application effectively solves the problem that traditional evaluation methods cannot observe the dynamic evolution of plasma, can accurately measure the key time parameters and intensity parameters of plasma activity, establishes a direct correlation between the radiation resistance performance of materials and the dynamic characteristics of plasma, and provides a reliable experimental basis for optimizing cerium doping concentration and glass composition.

[0080] As one possible implementation method, shock wave evolution analysis specifically includes: Determine the occurrence and delay time of the first occurrence of the shock wave, and further mark the initial shock wave and the secondary shock waves surrounded by the initial shock wave; Analyze the propagation paths of the initial shock wave and the secondary shock wave as the delay time increases; The time for the secondary shock wave to completely dissipate is obtained, and the radiation resistance of the sample to the shock wave is evaluated based on the complete dissipation time. Calculate the relationship between the propagation distance of the initial shock wave and the number of waves, as well as the relationship between the propagation distance and the delay time. The propagation distance is the vertical distance from the peak of the initial shock wave to the front surface of the target sample. The radiation resistance of the sample to shock waves is evaluated based on the transmission distance.

[0081] The number of times a laser pulse acts on a sample refers to the number of times the laser pulse acts on the sample. This can be achieved using a laser emission count counter, which is used to characterize the cumulative effect of the shock wave.

[0082] The delay time refers to the time interval from the triggering of the laser pulse to the appearance of the shock wave. Specifically, it can be measured synchronously using a high-speed photodetector and a time-to-digital converter to determine the start time of the shock wave generation.

[0083] The initial shock wave refers to the first main peak of the shock wave, while the secondary shock wave refers to the secondary peak generated by the reflection or superposition of the energy of the initial shock wave. Specifically, the difference in the shape of the wave peak can be captured by a high-speed shadow imaging system to distinguish the influence of the primary and secondary shock waves on the material.

[0084] The transmission distance refers to the vertical distance from the peak of the initial shock wave to the front surface of the sample. Specifically, image processing algorithms can be used to extract the peak position coordinates and calculate the spatial displacement to quantify the energy attenuation characteristics during the propagation of the shock wave.

[0085] Specifically, by recording the number of initial shock waves and their delay time, the energy threshold and triggering conditions for shock wave generation can be clearly identified. After labeling the initial and secondary shock waves, high-speed imaging technology is used to continuously capture the wave crest morphology at different delay times, allowing for dynamic analysis of the shock wave's diffusion path and energy distribution changes within the material. The determination of the complete dissipation time of the secondary shock wave reflects the material's absorption efficiency of the shock energy; a shorter dissipation time indicates a stronger energy dissipation capability. By establishing a correlation model between transmission distance, number of initial shock waves, and delay time, the relationship between shock wave propagation rate and material structural properties can be revealed. For example, a decrease in the rate of increase in transmission distance indicates that internal defects or grain boundaries in the material impede shock wave propagation.

[0086] Compared to existing technologies, traditional methods assess radiation resistance solely through changes in transmittance or laser damage threshold, failing to capture the dynamic propagation patterns of shock waves and the interaction between primary and secondary waves. This approach, through high-speed imaging and spatiotemporal correlation analysis, enables in-situ observation of the shock wave propagation path, energy attenuation, and dissipation process. Furthermore, it introduces quantitative indicators of transmission distance and dissipation time, providing multi-dimensional dynamic data support for radiation resistance evaluation.

[0087] Through the above technical solution, this application solves the problem that existing technologies cannot analyze the propagation path and dynamic evolution of shock waves, and realizes a quantitative evaluation of the material's resistance to shock wave radiation. By distinguishing the propagation characteristics of initial and secondary shock waves, the contribution of different shock wave components to material damage can be clarified; through the correlation analysis of transmission distance with the number of shock waves and the delay time, the influence mechanism of the material's microstructure on shock wave energy dissipation can be revealed, providing data basis for optimizing the material's radiation resistance performance.

[0088] In a second aspect, the present invention provides a laser damage evaluation system for cerium-doped barium borosilicate optical glass, comprising: a pump-probe shadow imaging module and a laser damage evaluation module; Among them, the pump-probe shadow imaging module is used to acquire the laser damage threshold, transmittance under preset band and preset working conditions of N cerium-doped barium borosilicate optical glass samples with different doping concentrations, as well as the damage image set of the target sample. The damage image set consists of the initial transient damage image of the side, the initial and final transient damage image of the side, the initial transient damage image of the front surface, the initial and final transient damage image of the front surface, and the transient damage image of the front surface, the final damage image of the front surface, the transient damage image of the side, and the final damage image of the side after different number of shots and delay times. The laser damage resistance evaluation module evaluates samples from six dimensions: laser damage threshold, transmittance under preset wavelength and preset working conditions, crack evolution under different firing times and different delay times, damage size evolution, plasma evolution, and shock wave evolution. Based on the evaluation results, the target sample with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance is selected.

[0089] Among them, the pump-probe shadow imaging module refers to an optical imaging device used to acquire transient and final damage images of a sample under laser action. Specifically, it can be implemented using a high-speed shadow imaging system that synchronously triggers femtosecond laser pumping and nanosecond probe light. By adjusting the firing interval of the pump laser and the delay time of the probe light, image sequences of different damage stages can be obtained.

[0090] The laser damage evaluation module is an assessment unit based on multidimensional data analysis. Specifically, it can be implemented using image processing algorithms and parameter calculation models. By extracting crack propagation paths, damage area sizes, plasma intensity distributions, and shock wave propagation trajectories from damage images, dynamic evolution data can be generated.

[0091] Specifically, the pump-probe shadow imaging module generates high-energy pulses using a femtosecond laser to induce damage on the sample surface, while simultaneously capturing transient and final-state images of the damaged area at different delay times using nanosecond-level probe light. Initial transient damage images of the side surface are acquired using a lateral high-speed camera, recording the crack initiation state at the moment of damage occurrence; initial and final-state damage images of the front surface are acquired using a high-speed camera in an orthogonal direction to determine the geometric characteristics of the initial damage. The laser damage resistance evaluation module uses the laser damage threshold and transmittance as static screening indicators, combined with dynamic evolution parameters to construct a comprehensive evaluation model. For example, in crack evolution analysis, by comparing the transient side images at different firing rates, the propagation direction of newly added radial cracks is identified; in shock wave evolution analysis, by tracing the propagation paths of the initial and secondary shock waves, their dissipation time and transmission distance are calculated.

[0092] Compared to existing technologies, which rely on single static parameters such as transmittance changes or laser damage thresholds, this approach fails to capture transient phenomena during the damage process. Our proposed solution utilizes a pump-probe shadow imaging module to achieve in-situ observation of crack propagation, plasma generation, and shock wave propagation. The laser damage resistance evaluation module integrates static parameters and dynamic evolution data, establishing a multi-dimensional evaluation system. For example, existing technologies cannot quantify the ratio of damage pit depth to radial dimension, while this solution extracts the maximum damage depth and radial dimension from the final-state damage image and calculates the change in this ratio to assess the stability of the damage morphology.

[0093] Through the above technical solution, this application solves the problem in the prior art that it cannot dynamically reflect the crack evolution, plasma generation, and shock wave propagation of cerium-doped glasses during laser damage. The transient image set acquired by the pump-probe shadow imaging module can record the spatiotemporal characteristics of damage evolution in situ; the laser damage resistance evaluation module, combining data from six dimensions, achieves a comprehensive quantitative assessment of the material's radiation resistance, shock wave resistance, and crack propagation resistance, providing a reliable basis for screening cerium-doped glasses with high laser damage resistance.

[0094] To facilitate understanding of the technical solution of this application, further explanation is provided below with reference to specific embodiments.

[0095] Example 1 Existing methods for evaluating the resistance of materials to laser-induced damage rely solely on static numerical indicators such as transmittance or laser damage threshold, lacking a systematic evaluation of the dynamic damage process. In particular, they lack in-situ observation and quantitative description of transient phenomena such as crack evolution, plasma generation, and shock wave propagation. This embodiment provides an in-situ observation system and quantitative evaluation method focusing on crack evolution, plasma generation, and shock wave propagation.

[0096] (1) Prepare four cerium-doped barium borosilicate optical glass samples with different doping concentrations. A series of Ce-doped glass samples were prepared using melt-quenching technology, with nominal compositions of [missing information]. The samples were named G1, G2, G3, and G4, respectively. High-purity (≥99.99%) samples were then used. , , , and The oxide powders were mixed in a specific ratio. The mixture was pre-melted at 1250°C, followed by high-temperature melting at 1420°C for 6 hours in an ambient atmosphere. Subsequent heat treatment included annealing at 650°C for 20 hours and controlled cooling. The final sample was cut into 50×10×3 mm³ pieces and polished across the entire surface. According to... With increasing doping concentration, the four samples were named G1-G4 sequentially, all exhibiting a pale yellow and transparent characteristic. Before laser irradiation, the samples were placed in a buffered hydrofluoric acid solution. Etch for 15 minutes to obtain a clean surface.

[0097] (2) Laser damage evaluation system for cerium-doped barium borosilicate optical glass A laser damage resistance evaluation system for cerium-doped barium borosilicate optical glass was constructed. The system components are described in [link to system description]. Figure 2 The evaluation system used in this embodiment consists of a pump-probe shadow imaging system. The system operating conditions and parameter settings are as follows: During testing, the glass sample was placed on an XYZ translation stage, and two Nd:YAG lasers were used as the pump source and the probe source, respectively. The pump laser (wavelength 355nm, pulse width 10ns) passed through a lens (focal length f=100mm). The substrate is focused on the front surface of the sample.

[0098] The light spot exhibits a spatial Gaussian distribution. The spot diameter is approximately 500 μm. The pump laser uses a single-trigger mode with a pulse interval of 60 seconds to completely eliminate the heat accumulation effect.

[0099] A probe laser (wavelength 532 nm, pulse width 8 ns) illuminates the sample after passing through a half-wave plate and a polarizer. A beam splitter divides the probe laser into two beams, capturing damage images of the sample's front and side surfaces respectively. A mirror assembly adjusts the optical path difference between the two probe beams to ensure that CCD1 and CCD2 can simultaneously capture the same damage event.

[0100] The delay time is defined as the time interval between the pump laser peak and the probe laser peak. This parameter is precisely controlled by a digital delay generator (DG645) and measured in real time using an oscilloscope with a sampling rate of 1.25 GSa / s and a maximum storage depth of 50 Mpts. By adjusting the delay time, the evolution of surface damage can be observed. The imaging system includes a CCD camera and a 4x magnification telephoto objective lens, providing transient and final images with a resolution of 5 μm. The CCD2 camera... The camera is positioned relative to the sample to avoid pump laser interference. A 532nm bandpass filter and a neutral density filter are used to reduce stray light and protect the camera. A mechanical shutter is also installed to ensure that the pump laser and probe laser irradiate the sample simultaneously.

[0101] (3) Test the laser damage threshold and transmittance of the samples to select the samples to be tested in subsequent tests. First, the laser damage threshold and transmittance of the prepared samples were tested. The results of the laser damage threshold and transmittance tests are shown in [reference needed]. Figure 3 and Figure 4 , Figure 3 The study presents the probability of damage from a 355nm laser on four different samples and the relationship between the 355nm laser damage threshold and the Ce-doped concentration. Figure 4 The transmittance curves of four samples are presented. The test results show that G2 has the highest laser damage threshold, followed by G1. However, while G2 has the highest laser damage threshold, its absorption coefficient is also correspondingly high. A higher absorption coefficient indicates that the cerium-doped glass has strong absorption characteristics for ultraviolet light, potentially making it more susceptible to laser-induced damage under high-power ultraviolet laser irradiation. This means that the damage change during the transition from an intact state to a damaged state is relatively larger. Therefore, it is necessary to clearly identify the critical point of damage mode transition under repeated irradiation, i.e., to quantify the balance between the material's radiation resistance and the absorption coefficient / laser damage threshold through damage kinetic studies. Thus, further research on its damage evolution process is needed. This involves using laser damage kinetic testing methods to test and observe the crack evolution, damage size evolution, plasma evolution, and shock wave evolution of the glass material. By evaluating these four properties, the overall performance of the glass material can be assessed to determine the optimal composition ratio.

[0102] (4) Perform laser damage dynamics testing on the sample to be tested and analyze the test results. By testing the laser damage threshold and transmittance, the two samples with the highest laser damage threshold and transmittance were selected as test samples for further testing. In this embodiment, the G2 sample (with the highest laser damage threshold) was used as an example to analyze and evaluate in detail the crack evolution, damage size evolution, plasma evolution, and shock wave evolution of the G2 sample under different firing times and different delay times.

[0103] ①Crack evolution Crack evolution is quantified by the size of the damaged area and the radial crack size.

[0104] For the damage kinetics-crack evolution test results of G2, please refer to [link / reference]. Figure 5 , Figure 5 Transient and final images of the initial damage and subsequent damage growth on the front surface of the radiation-resistant glass under different exposure times and delay times are shown.

[0105] in, Figure 5 Images (a)-(l) show the side views of the damage under different firing times and delay times. The black stripes represent the front surface of the sample, with the laser incident direction to its left.

[0106] in, Figure 5 The images (m)-(x) represent the front surface images under different firing orders and different delay times, which can clearly distinguish between radial cracks and circumferential cracks.

[0107] in, Figure 5 (a) and Figure 5 The middle (g) diagram shows the transient and final states of the sample under initial damage.

[0108] in, Figure 5 Middle (m) and Figure 5 The image in s is a transient and final state diagram of the sample surface before initial damage.

[0109] For ease of description, Figure 5 In (i), the area within the red box is defined as the core damage area, and the purple arrow indicates the damage path.

[0110] It can be seen that the initial damage crack was basically formed within 188 ns. The damage area mainly includes the core damage region (Cda) and the small radial crack RC1. The core damage region contains high-density melt, which is the main reason for the reduced transmittance. By comparison, it can be determined that... Figure 5 The core damage area in (g) and Figure 5 The core damage region corresponds to the frontal final state image in the middle (s) image. During subsequent energy deposition, the diameter of the core damage region continuously increases, while the radial crack RC1 continues to develop along the damage path.

[0111] like Figure 5 As shown in (b), a bright plasma flash can be observed with a delay time of 30 ns, but the shock wave has not yet been generated. Compared to Figure 5In the middle (h) state, the crack size at the final damage state is significantly larger. This indicates that the propagation of the radial crack RC1 has not completely ended within 30 ns. It can be determined that the crack will continue to propagate after the laser pulse irradiation ends, with the propagation time being much longer than the laser pulse width. It is noteworthy that during damage growth, plasma generation and crack propagation both take precedence over shock wave formation. Figure 5 (h) Figure 5 In the middle (t), compared with the initial damage, a significant damage growth phenomenon was observed. RC1 continued to extend along the damage path, and the crack size increased. Moreover, new radial cracks RC2 and RC3 appeared, developing perpendicular to the damage path. It can be determined that... Figure 5 The longitudinal expansion of the frontal damage image in (t) is closely related to the generation of RC2 and RC3.

[0112] The radial cracks RC1, RC2, and RC3 exhibited different development trends in subsequent cracks. RC1 continued to develop along the damage path, but its size remained almost unchanged after the sixth crack; RC2 gradually evolved into RC21 and RC22, as shown in the diagram. Figure 5 As shown in (j). RC21 continues to extend perpendicular to the damage path, while RC22 tends to extend towards the forward surface; as... Figure 5 By the 10th shot, RC3 had transformed into a circumferential crack CC3. From the 10th shot onwards, cracks resembling those seen from the side and front could be observed. Figure 5 In (d) CC1 and such Figure 5 The circumferential cracks shown in CC2 and CC3 in (v) are as follows. When the number of laser blasts increases to 15, as... Figure 5 As shown in (k), RC11 and RC12 both develop toward the front surface and evolve into circumferential crack CC5.

[0113] It can be inferred that some circumferential cracks evolve from radial cracks, and the energy required to generate circumferential cracks is greater than that required to generate radial cracks. It can be determined that... Figure 5 The annular crack CC5 in (k) and Figure 5 The annular crack CC5 in (w) corresponds to this. (By comparison) Figure 5 (v) and Figure 5 As shown in (w), the propagation rate of circumferential cracks is much faster than that of radial cracks. Although new radial cracks, such as RC4, still form, the propagation of circumferential cracks begins to dominate the increase in damage size.

[0114] When the number of laser pulses reached 20, the damage depth remained essentially unchanged, but the lateral dimension of the damage continued to increase, such as... Figure 5 A new radial crack RC5 is added in (f). For example... Figure 5 As shown in (x), the diameter of the frontal damage pit has reached 1142 μm, and the radial crack region is gradually filled with molten material.

[0115] ② Evaluation of damage size evolution Damage size evolution is determined by the diameter-to-depth ratio (D / H) and area ratio (D / H). ) to be quantified.

[0116] Depend on Figure 5 The test results shown indicate that after different cumulative pump laser irradiations, the damage area, damage depth, and radial size of the damage pit all exhibit different growth trends.

[0117] Define the maximum radial dimension of the front surface damage pit as D, and the area of ​​the core damage region as... The total area of ​​damage is These parameters are obtained from the frontal image.

[0118] Defined as damage depth H, this parameter is obtained through side images, which means that the distance between the farthest point along the damage path and the front surface can be measured, and this distance is H.

[0119] The test results can be found here. Figure 6 ,Depend on Figure 6 It can be seen that the damage growth process can be divided into two stages. In stage 1, the increase in damage depth and radial dimension is basically the same, and the diameter-to-depth ratio stabilizes at around 0.8. However, in stage 2, the damage tends to extend radially. For each pulse, the increase in damage depth does not exceed 10 μm, while the radial dimension increases linearly at a rate of nearly 100 μm per pulse. Therefore, the diameter-to-depth ratio decreases rapidly. When 20 pulses are accumulated, the diameter-to-depth ratio has dropped to 0.33. Furthermore, Figure 7 This indicates that with increasing laser irradiation cycles, the areas of both the core damage region and the surrounding cracks continuously increase. However, the proportion of the core damage region in the total damage area gradually decreases. In the second stage, crack propagation begins to dominate the growth of the damage area. Entering the third stage, the area of ​​the core damage region remains essentially constant, eventually reversing the relationship with the area of ​​the surrounding cracks. Notably, when the 16th laser irradiation cycle is reached, the area of ​​the core damage region is approximately 0.194. It is already close to the spot size of the pump laser.

[0120] ③ Evaluation of plasma evolution When a laser bombards the surface of a glass material, plasma is inevitably generated. The generation of plasma and the propagation of shock waves will cause further damage to the surface of the material. This damage greatly affects the working condition of the material. As the number of irradiations increases, the intensity of the plasma continues to increase, and as the depth of damage increases, it gradually extends into the sample.

[0121] The greater the absorption of a material, the stronger its ability to absorb ultraviolet laser light, which in turn has a greater impact on the material's damage behavior. Therefore, it is necessary to evaluate plasma evolution to obtain the influence of the absorption coefficient on the material's damage behavior.

[0122] See plasma generation observation results Figure 8 ,according to Figure 8 The observed plasma generation results show that the plasma density region goes through three stages: Plasma initiation phase: 20~40ns, which is the initial luminescence phase of the plasma; Plasma enhancement phase: 40~100ns, which is the phase of increasing plasma peak intensity, reaching its strongest point in the time range of 80ns~100ns; Plasma decay phase: 100~220ns, which is the plasma decay and disappearance phase.

[0123] Depend on Figure 8 The results show that, starting from the third laser irradiation, a significant plasma flash area can still be observed within the core damage region.

[0124] With increasing irradiation cycles, the plasma intensity continuously increases and extends into the sample cavity as the damage depth increases. This can be attributed to the damage cavity generated within the core damage region after a large amount of energy deposition. Numerous sputtered particles and molten material particles remain on the inner walls and bottom of the damage cavity. This inevitably enhances the absorption of pump laser energy in the damaged area, resulting in a more pronounced plasma flash. Simultaneously, as the damage cavity extends into the sample cavity along the damage path, the plasma concentration area also extends accordingly.

[0125] Under multiple pulsed irradiations, a consistent temporal behavior was observed in the transient evolution of sample damage, such as... Figure 8 As shown. For all pulses, the complete damage process is limited to within 350 ns.

[0126] Figure 9 The image shows transient images of the side view at different delay times after the fifth pump laser irradiation. It can be seen that the plasma concentration region exists for approximately 20–210 ns. During this period, the plasma intensity varies with the delay time. Figure 9 In (a), sporadic plasma generation can be observed when the delay time reaches approximately 20 ns. At a delay time of 42 ns, a concentrated plasma region has formed, as shown in Figure (a). Figure 9 (b) The plasma concentration region reaches its peak in the time range of 40 ns to 60 ns. As the crack propagates and the shock wave is generated, the plasma intensity gradually weakens. Until the delay time reaches 212 ns, as shown... Figure 9 As shown in (e), the plasma flash can be observed to have just disappeared.

[0127] ④ Evaluation of shock wave evolution The formation of shock waves has a relative lag. The shock wave first appears around the 5th shock wave, about 100 ns, and dissipates within 320 to 350 ns.

[0128] exist Figure 9 In (c), after the 5th shock, when the delay time reaches 92 ns, two hemispherical shock waves can be observed in the air. The outermost shock wave is called the initial shock wave, denoted as SW1. The inner shock wave surrounded by SW1 is the secondary shock wave, denoted as SW2.

[0129] These two shock waves were formed by compressed air containing different ejected materials: SW1 was mainly formed by compressed air containing plasma, while SW2 was mainly formed by compressed air containing neutral particles such as ejected sample fragments and particulate matter. Since the shock waves had just been generated, SW1 and SW2 had not yet completely separated. Therefore, in Figure 9 In (c), the boundary between SW1 and SW2 is not obvious. Figure 9 In diagram (d), shock waves SW1 and SW2 can be clearly observed. Obviously, the propagation speed and intensity of SW1 are much greater than those of SW2. Therefore, in... Figure 9 In (e), SW2 has dissipated, while SW1 continues to propagate through the air. Notably, due to the compression effect of the ejecta, a cone-shaped protrusion appears at the leading edge of shock wave SW1. This further confirms that ejecta particles alter the morphology of shock waves. (Comparison...) Figure 9 (f) and Figure 10 In (f), it can be observed that all transient processes during the damage process include plasma flash, crack propagation, shock wave propagation, and material splashing.

[0130] The distance D from the crest of the shock wave SW1 to the front surface of the sample is defined as the transmission distance of the shock wave. S .like Figure 11 As shown, D is the dividing point between the 8th and 10th shots. S With increasing irradiation frequency, the trend shows an initial decrease followed by an increase. Combined with... Figure 6 It can be determined that within the first 10 strikes, the gradual deepening of the damaged cavity affected the propagation efficiency of the shock wave into the air. However, starting from the 10th strike, the damage depth remained essentially constant, while the radial dimension of the damaged cavity rapidly increased. This resulted in a weakening of the damaged cavity's attenuation effect on the shock wave.

[0131] Simultaneously, with increasing irradiation cycles, the number of cracks and large particles within the damage crater increases, enhancing the absorption of pump laser energy. The more intense thermal explosion intensifies the compression of air by the plasma. Therefore, the transmission distance of the shock wave gradually increases. Furthermore, with increasing delay time... The gradual decrease reflects the attenuation of the shock wave's speed and the loss of energy as it propagates through the air.

[0132] (5) Compare the damage kinetic test results of the test samples. This embodiment uses sample G2 as an example to analyze its damage kinetics test results. Similarly, the damage kinetics test results of sample G1 are analyzed. By completing the analysis of the damage kinetics test results of G2 and G1, and comparing the various quantitative parameters of G2 and G1, the target sample with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance is obtained.

[0133] By comparing G2 and G1 under the same laser pulse (355nm, 8ns, 14.8... A comparative analysis of the damage kinetics results under irradiation leads to the following conclusions: Crack propagation was completed within 350 ns, exhibiting a three-stage evolution: Stage I: Radial crack propagation; Stage II: Radial cracks transform into circumferential cracks; Stage III: Circumferential crack propagation dominates.

[0134] Time parameters are affected Content control, high concentration accelerates crack evolution dynamics.

[0135] Both transient dynamics and final damage morphology are Ce concentration-dependent.

[0136] The final damage morphology also showed a clear dopant concentration dependence.

[0137] The laser damage resistance evaluation method for cerium-doped barium borosilicate optical glass provided by this invention was used to conduct damage kinetic tests and analyses on multiple samples. By comparing various quantitative parameters, sample G2 was determined to be the final target sample.

[0138] The evaluation of laser damage resistance of cerium-doped barium borosilicate optical glass cannot be limited to Ce doping concentration. Test results show that although high Ce doping concentration can improve the radiation resistance of the glass material, it also increases the laser damage it is susceptible to. At the same time, it is not possible to evaluate it solely using static / final state parameters such as laser damage threshold and transmittance. Traditional evaluation methods only analyze static parameters such as transmittance and laser damage threshold. When evaluating this series of materials using traditional methods, multiple samples can meet the usage requirements, but it is impossible to further clarify the evolution process of laser damage in the material.

[0139] The laser damage evaluation method for cerium-doped barium borosilicate optical glass provided by this invention tracks the damage morphology changes under different laser strikes over time, and combines the transient characteristic analysis of plasma and shock waves to establish a comprehensive performance evaluation model. This method overcomes the limitations of simple numerical evaluation, realizes in-situ visual monitoring of the damage process, and provides an effective evaluation method for the refined design of materials.

[0140] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and other materials. In this specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the specification. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0141] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the invention and its equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass, characterized in that, Includes the following steps: Samples of N cerium-doped barium borosilicate optical glasses with different doping concentrations were prepared; The evaluation results were obtained by evaluating the samples from six dimensions: laser damage threshold, transmittance under preset wavelength and preset working conditions, crack evolution under different firing times and different delay times, damage size evolution, plasma evolution, and shock wave evolution. Based on the evaluation results, the target samples with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance were selected.

2. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 1, characterized in that, First, based on the laser damage threshold at the same wavelength and the transmittance under preset bands and preset working conditions, samples to be evaluated are selected from N samples. Then, the crack evolution, damage size evolution, plasma evolution, and shock wave evolution of the sample to be evaluated are carried out under different number of shocks and different delay times to obtain the target sample and its corresponding evaluation results.

3. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 2, characterized in that, The sample to be evaluated has the highest laser damage threshold and the transmittance under the preset wavelength and preset working conditions is greater than or equal to the transmittance threshold.

4. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 1, characterized in that, The evaluation of crack evolution under different bursts and different delay times includes the following steps: Obtain a set of damage images of the sample to be evaluated. The set of damage images includes the initial transient damage image of the side, the initial and final transient damage image of the side, the initial transient damage image of the front surface, the initial and final transient damage image of the front surface, and the transient damage image of the side, the final damage image of the side, the transient damage image of the front surface, and the final damage image of the front surface at different times and delay times after the initial damage. The initial damage region and the time of its occurrence are determined based on the initial transient damage image of the side surface, the initial transient damage image of the side surface, the initial transient damage image of the front surface, and the initial transient damage image of the front surface. The initial damage region includes the core damage region and the initial radial crack. Based on the transient damage images of the front surface, the final damage images of the front surface, the transient damage images of the side surface, and the final damage images of the side surface under different occurrences and delay times after the initial damage, the size changes of the core damage region, the size changes of the initial radial crack, the propagation path of the initial radial crack, as well as the size changes of the newly added radial crack and the propagation path of the newly added radial crack are dynamically deduced.

5. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 4, characterized in that, The evaluation of damage size evolution under different number of attacks and different delay times includes: The maximum radial dimension D and maximum damage depth H of the damage pit are obtained from the final damage images of the front surface and the side surface at each shot and at each delay time. The ratio between the maximum damage depth H and the maximum radial dimension D is further calculated. Based on this, the changes of the maximum radial dimension D, the maximum damage depth H, and the ratio between the maximum damage depth H and the maximum radial dimension D are dynamically deduced.

6. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 4, characterized in that, The evaluation of damage size evolution under different number of attacks and different delay times also includes: The area of ​​the core damage region is obtained from the final state damage image of the front surface at each shot and each delay time. and the total area of ​​the damage pit And further calculate the area ratio Based on this, the area of ​​the core damage region is dynamically estimated. Total area of ​​the damage pit Area ratio The changes.

7. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 1, characterized in that, Plasma evolution analysis specifically includes: A set of transient damage images of the side at different delay times after a specific number of shots was obtained, where the specific number of shots refers to the first time plasma appears; The start and end points of the plasma appearance delay time were determined based on the set of lateral transient damage images; Within the range of the start and end points, the plasma intensity change is determined and divided into different stages, including the plasma initiation stage, the plasma enhancement stage, and the plasma decay stage; The radiation resistance of the sample to plasma is evaluated based on the peak intensity and duration of the plasma enhancement phase.

8. The method for evaluating the laser damage resistance of cerium-doped barium borosilicate optical glass according to claim 7, characterized in that, Shock wave evolution analysis specifically includes: Determine the occurrence and delay time of the first occurrence of the shock wave, and further mark the initial shock wave and the secondary shock waves surrounded by the initial shock wave; Analyze the propagation paths of the initial shock wave and the secondary shock wave as the delay time increases; The time for the secondary shock wave to completely dissipate is obtained, and the radiation resistance of the sample to the shock wave is evaluated based on the complete dissipation time. Calculate the relationship between the propagation distance of the initial shock wave and the number of waves, as well as the relationship between the propagation distance and the delay time. The propagation distance is the vertical distance from the peak of the initial shock wave to the front surface of the target sample. The radiation resistance of the sample to shock waves is evaluated based on the transmission distance.

9. A laser damage evaluation system for cerium-doped barium borosilicate optical glass, characterized in that, include: Pump-probe shadow imaging module and laser damage assessment module; Among them, the pump-probe shadow imaging module is used to acquire the laser damage threshold, transmittance under preset band and preset working conditions of N cerium-doped barium borosilicate optical glass samples with different doping concentrations, as well as the damage image set of the target sample. The damage image set consists of the initial transient damage image of the side, the initial and final transient damage image of the side, the initial transient damage image of the front surface, the initial and final transient damage image of the front surface, and the transient damage image of the front surface, the final damage image of the front surface, the transient damage image of the side, and the final damage image of the side after different number of shots and delay times. The laser damage resistance evaluation module evaluates samples from six dimensions: laser damage threshold, transmittance under preset wavelength and preset working conditions, crack evolution under different firing times and different delay times, damage size evolution, plasma evolution, and shock wave evolution. Based on the evaluation results, the target sample with the highest laser damage threshold, the highest visible light transmittance, and the strongest radiation resistance is selected.

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