单脉冲激光对CCD探测器的硬损伤及损伤概率

Damage phenomenon and probability of CCD detectors under single-laser-pulse irradiation

在纳秒激光脉冲辐照下,随着CCD探测器损伤程度的加深,成像系统输出画面中先后出现点损伤、白线损伤以及完全失效等现象,且损伤阈值呈现出概率分布特性。实验激光波长为1064nm,首先采用n-on-1辐照模式,研究CCD探测器在不同损伤程度下的损伤现象,从器件工作原理的角度分析各种现象出现的机理。利用光学显微镜观察样品的损伤形貌,发现探测器的损伤部位从内部材料开始,逐渐发展到位于表面的微透镜结构。接下来,采用1-on-1辐照模式测量了点损伤和完全失效阶段的激光能量密度阈值,并以损伤概率的形式进行描述,得到实验样品的完全失效阈值在100 mJ/cm2左右。

When CCD detectors damaged by nanosecond pulsed laser, with the deepening of damage degree, the phenomena of point damage, white line damage and complete failure appear successively in the output pictures of the imaging system, and the damage thresholds exhibit a nature of probability distribution. The laser wavelength was 1 064 nm in our experiment. At first, the CCD detectors were illuminated with n-on-1 mode, three different degrees of damage behaviors were observed, and the damage mechanism was analyzed on basis of the working principle of the CCD imaging system. The damage morphology of the samples were studied with an optical microscope, and it is found that the damage initiates from the inner part of the detectors and then spreads to the micro-lens structure on the surface. Next, the irradiation mode of 1-on-1 was employed to measure the damage thresholds for the degree of point damage and system failure. The former is expressed in the way of probability distribution, and the thresholds of system failure are around 100 mJ/cm2.