A reliable method, combining femtosecond (fs) laser mitigation and chemical (HF) etching, has been developed to mitigate laser-damage growth sites on a fused silica surface. A rectangular mitigation site was fabricated by an fs laser with a raster scan procedure; HF etching was then used to remove the redeposition material. The results show that the mitigation site exhibits good physical qualities with a smooth bottom and edge. The damage test results show that the growth threshold of the mitigation sites increases. Furthermore, the structural characteristic of samples was measured by a photoluminescence (PL) spectrometer, and the light intensification caused by damage and mitigation sites was numerically modeled by the finite-difference time-domain (FDTD). It revealed that the removal of damaged material and structure optimization contribute to the increase of the damage growth threshold of the mitigation site.
© 2013 Optical Society of America
Lasers and Laser Optics
Original Manuscript: June 17, 2013
Revised Manuscript: September 17, 2013
Manuscript Accepted: September 20, 2013
Published: October 10, 2013
Zhou Fang, Yuan’an Zhao, Shunli Chen, Wei Sun, and Jianda Shao, "Method of mitigation laser-damage growth on fused silica surface," Appl. Opt. 52, 7186-7193 (2013)