石英光学元件激光损伤修复形貌的优化

Abstract

Aiming at morphology of laser induced damage mitigation pit on the rear surface of 3omegasilica optical component,the mitigated area and its downstream intensity distributions with different morphologies are simulated by finite-difference time-domain method (FDTD)and Rayleigh-Sommerfeld (R-S)diffraction integral method, respectively.The results show that when the angle between the tangent line of endpoints on the section contour of the pit and incident light is over 70°,the maximum intensity inside the mitigated optics is less than 1.66,and mitigation effect is better than that of other angles.The maximum downstream intensities of a pit in shape of parabolic surface,cone and truncated cone are all less than 1.46with an angle of 70°and a width of 200mum.But when the width of pit increases to 1mm,for instance,the maximum downstream intensity is as high as 9.31and area with high intensity covers a long range.Thus,taking the difficulty of laser machining technology into account, a conical pit with an angle larger than 70°is the first choice for the damage mitigation on the rear surface of silica optical component.