薄膜激光损伤阈值标定技术

为了满足薄膜激光损伤阈值客观、准确、高精度测量的要求, 提出了损伤阈值标定技术。通过互换两个能量探测器位置的试验标定方法, 消除分光镜的分光误差和能量探测器的测量误差, 获得准确的辐照能量。再通过调整两个CCD位置获得相同光斑尺寸的测量方法标定被测样品表面与光斑面积测量面的等效, 并剔除激光光斑中非平顶部分, 获得准确的辐照光斑面积。最后采用最小二乘法对计算得到的能量密度及其对应的损伤几率进行拟合, 获得损伤阈值。通过对TiO₂/SiO₂高反射膜1064nm激光辐照测量实验, 得到23.0164J/cm2的薄膜激光损伤阈值。结果表明, 采用标定技术使薄膜激光损伤阈值的测量精度提高了9.26%, 满足高精度的测量要求。此研究有助于薄膜激光损伤阈值的准确标定。

Calibration technology of laser-induced damage threshold of thin films

In order to meet the requirements of objective, accurate, and high-precision measurement of laser damage threshold of thin films, the calibration technology of damage threshold was proposed. Firstly, the experimental calibration method of exchanging the positions of the two energy detectors was used to eliminate the error of the spectroscope and the measurement of the energy detector, so as to obtain the accurate irradiation energy. Then, the measurement method of adjusting the positions of two CCD devices to obtain the same spot size was used to calibrate the equivalence between the measured sample surface and the spot area measurement surface, and the non flat top part of the laser spot was eliminated, so as to obtain the accurate irradiation spot area. Finally, the least square method was used to fit the calculated energy density and the corresponding damage probability to obtain the damage threshold. The 1064nm laser irradiation experiment of TiO₂/SiO₂ high reflection film was carried out, and the laser damage threshold was 23.0164J/cm2. The results show that the measurement accuracy of laser damage threshold is increased by 9.26% by using calibration technology, which meets the high precision measurement requirements. This study is helpful for accurate calibration of laser damage threshold of thin films.