激光诱导透明陶瓷损伤研究进展

Research Progress on Laser Induced Damage to Transparent Ceramics

在激光诱导损伤的响应中,透明陶瓷既有与其他光学元件的相似性,也表现出损伤的特殊性因其具有晶界、微气孔等微结构缺陷。强激光对透明陶瓷诱导损伤的形貌、分析损伤的规律并揭示损伤的机理的工作被开展,这有利于完善激光陶瓷的制备工艺,对降低高能激光系统的运行成本和提高负载能力均具有现实意义。本文综述了透明陶瓷激光诱导损伤的探究方法、损伤的影响因素和提升损伤阈值的途径3方面内容,并结合其他类光学元件较为成熟的研究思路或典型的探究方法。探讨了激光诱导透明陶瓷损伤中的几个研究重点及解决对策,对于高损伤阈值透明陶瓷的研制以及在强激光系统中的合理应用具有重要的参考价值。

In the response to laser induced damage,transparent ceramics are similar to other types of optical components(i.e.,single crystals,fused quartz glass,etc.),such as surface and in vivo damage.However,they exhibit a particularity of damage due to its microstructure defects such as grain boundaries and micro pores.With the continuous development of high-power laser technology,transparent ceramics as laser gain media to resist laser damage are required.It is necessary to conduct in-depth research on the damage characteristics of transparent ceramics.In order to clarify the damage sources that induce damage to transparent ceramicsand the damage response caused by structural defects in transparent ceramics under intense laser irradiation as well as reveal the damage mechanism,the defect characterization and damage detection methods are also continuously developed and optimized.Among them,an online time-resolved imaging method represented via pump detection is developed.The evolution of stress waves and plasma,as well as their impact on damage to transparent ceramics are analyzed via time-resolved imaging.The damage characteristics and mechanism of transparent ceramics induced by strong laser are investigated by the online time-resolved imaging method.In addition,there are also many types of structural defects in transparent ceramics that are difficult to be accurately controlled.Therefore,it is possible to artificially regulate the source of damage,such as the size and density of micro pores.This can control uncontrollable micro-defects,greatly improving the efficiency of exploration.The damage research of transparent ceramics can be further innovated.This review represented the research methods of laser induced damage in transparent ceramics,the influencing factors of damage(i.e.,surface structural defects,micropores,and ceramic grain boundaries),and some approaches to increase the damage threshold.Transparent ceramics are the gain medium in high power laser systems,and there are two main reasons for inducing laser damage.On the one hand,it is related to the input laser parameters,but more importantly,the main damage sources in transparent ceramics(i.e.,surface roughness,ceramic grain boundaries,and micro-pores)lead to an irreversible damage under high power laser induction.This aspect becomes a recent research topic to explore the mechanisms and characteristics of various damage sources causing damage to transparent ceramics.To better explore the microscopic evolution process in the damage process,effectively analyze the damage mechanisms of transparent ceramics in macro-/meso-and micro-levels,and further explore some ways to improve the damage threshold of transparent ceramics,it is thus necessary to effectively combine line damage test,numerical simulation and theoretical calculation of multi-physical field coupling,and artificial defect control in multiple depths.A comprehensive analysis is carried out around the damage source in transparent ceramics to clarify the damage law,and gradually establish the correlation of“damage source-injury performance-injury mechanism”,and finally lay an important foundation for exploring a way to improve the damage threshold.A ultimate goal of research on laser damage to transparent ceramics is to explore effective ways to increase the damage threshold,in order to better ensure the application effect of transparent ceramics in practical engineering.This review thus discussed several possible implementation approaches for the damage threshold of transparent ceramics,i.e.,laser pretreatment,annealing process,and surface micro/nano processing.The three approaches are effectively validated in improving the laser damage threshold of other types of optical components.However,based on the polycrystalline properties of transparent ceramics themselves,it is still necessary to conduct systematic experiments and explorations to determine whether they can have a positive effect in improving the laser damage threshold in transparent ceramics.Summary and prospects This review summarized three aspects i.e.,the exploration methods of laser induced damage in transparent ceramics,the influencing factors of damage,and the ways to increase the damage threshold.The research progress on laser induced damage to transparent ceramics was elaborated,having an important reference significance in the related fields.To clarify the influence of structural defects such as micropores and grain boundary on the damage formation mechanism,a guidance for the control standards of structural defects in the preparation and processing of transparent ceramics was provided.This review also has an important reference value for the development of high damage threshold transparent ceramics and their reasonable application in high-power laser systems.The study of intense laser induced damage to transparent ceramics will continue to promote the expansion of related basic and applied science research,thereby providing a foundation/guidance for the design and manufacture of high-performance optical and optoelectronic devices.