随着激光器朝向大功率、 高能量的方向发展, 激光损伤阈值成为了衡量光学元件抗激光损伤能力的重要参数之一, 因此, 能否准确地测量出光学元件的激光损伤阈值成为研究的重点。 而光学元件激光损伤阈值测试的关键是能否准确地判别光学元件是否发生激光损伤。 为解决目前常见的损伤判别方法存在的精度低、 识别时间长、 适用材料范围窄、 操作复杂等不足, 提出了一种新的激光损伤的判别方法, 即等离子体诊断法。 以K9玻璃为例, 搭建激光损伤阈值的测试平台, 利用光纤光谱仪采集强激光辐照K9玻璃时所产生的激光等离子体闪光光谱, 并对该光谱进行诊断分析, 将该光谱中是否含有待测试光学元件材料中特征元素的光谱峰作为其是否收到激光损伤的标准。 同时, 对K9玻璃进行了激光损伤阈值的测试, 并将测试结果与等离子体闪光法和显微镜法所测的激光损伤阈值进行了对比分析。 实验表明, 提出的等离子体诊断方法的判别精度高、 速度快、 测试装置结构简单, 易实现在线测量, 可以大大地提高光学元件激光损伤阈值测试工作的效率。

With the development of the laser towards high-power and high energy, laser-induced damage threshold of optics becomes one of the important parameters to evaluate the laser damage resistance of optics. Therefore, accurately measuring of the laser-induced damage threshold optics become the focal point studied. And the key to accurately measuring of the laser-induced damage threshold is whether the laser-induced damage can be accurately identified when it occurs. In order to solve low accuracy, long testing time, narrow scope of applications and complex operation of the common damage identification methods, a new testing method to diagnose the laser-induced damage of optics, called plasma diagnosis, is proposed in this paper. Based on this new method, the testing platform was set up, and the spectrum obtained by fiber spectrometer was analyzed under laser radiation by different laser energies. Take whether the spectral lines of the feature element contained in the measured optics occur as standard. The laser-induced damage threshold of K9 glass has been tested, and the test result was compared to that measured by the plasma flash method and the microscope method. The results show that, the plasma diagnosis method proposed in this paper has high-accurate judgment, high-testing speed, simple testing equipment, and easy to realization, which can greatly improve the testing efficiency of the laser-induced damage threshold of optics.