光子学报, 2016, 45 (3): 0314003, 网络出版: 2016-04-01
平顶激光束诱导薄膜损伤阈值测量系统
Measurement System of Flattop Laser Induced Damage Threshold to Film
激光损伤阈值 薄膜 高斯光束 平顶光束 小波变换 二分查找 Laser induced damage threshold Film Gauss beam Flattop beam Wavelet transformation Binary search
摘要
为了满足快速、精确、定量地测量薄膜激光损伤阈值的要求,设计了平顶激光束诱导薄膜损伤阈值测量系统.介绍了损伤阈值测量的原理和方法,提出二分查找与顺序查找相结合的能量密度查找方式;根据分光镜的分光比及能量探测器示值求解辐照激光能量,用CCD成像法精密测量了作用在薄膜表面的激光光斑面积;基于小波变换法,通过图像处理精确识别了薄膜的损伤;建立能量密度与损伤几率坐标并进行最小二乘法拟合,对损伤阈值进行了标定.对45°高反射膜分别进行了高斯光束辐照和平顶光束辐照的测量实验,结果表明:高斯光束辐照测量的损伤阈值为9.95 J/cm2,平顶光束辐照测量的损伤阈值为13.98J/cm2,平顶光束诱导比高斯光束诱导的损伤阈值高40.5%.
Abstract
In order to measure the laser induced damage threshold to film quickly, accurately, and quantitatively, the measurement system of flattop laser induced damage threshold to film was designed. The principle and method of damage threshold measurement were introduced, and the energy density search method based on the combination of binary search and sequence search was proposed. According to the light splitting ratio of spectroscope and indicating value of energy deteclor, the irradiation laser energy was solved, using the CCD imaging method, the laser facula area which irradiated on the film surface was measured precisely. Based on wavelet transformation, the film damage was identified accurately by image processing. The coordinates of energy density and damage probability was established, and fitted by least square method, the laser induced damage threshold was calibrated. Experiments were carried out on 45° reflection films which were irradiated by Gauss beam and flattop beam, the measurement results show that the damage threshold of Gauss beam irradiation was 9.95J/cm2 and the flattop beam irradiation was 13.98 J/cm2,the damage threshold irradiation by flattop beam was 40.5% higher than that by Gauss beam.
王菲, 李玉瑶, 车英, 付秀华, 田明. 平顶激光束诱导薄膜损伤阈值测量系统[J]. 光子学报, 2016, 45(3): 0314003. WANG Fei, LI Yu-yao, CHE Ying, FU Xiu-hua, TIAN Ming. Measurement System of Flattop Laser Induced Damage Threshold to Film[J]. ACTA PHOTONICA SINICA, 2016, 45(3): 0314003.