The lifetime of optical components in high-fluence ultraviolet (UV) laser applications is typically limited by laser-initiated damage and its subsequent growth. Using 10.6-μm CO<sub>2</sub> laser pulses, we successfully mitigate 355-nm laser induced damage sites on fused silica surface with dimensions less than 200 μm. The damage threshold increases and the damage growth mitigates. However, the growth coefficients of new damage on the CO<sub>2</sub> laser processed area are higher than those of the original sample. The damage grows with crack propagation for residual stress after CO<sub>2</sub> laser irradiation. Furthermore, post-heating is beneficial to the release of residual stress and slows down the damage growth.
© 2011 Chinese Optics LettersPDF Article