Laser damage threshold measurements of 1064 nm high-reflection mirrors

Measurements of laser induced damage threshold(LIDT) of HfO2/SiO2 high-reflection (HR) dielectric mirrors at 1064 nm were performed using four different testing methods, 1-on-1, S-on-1, R-on-1 and raster scan, according to the ISO 11254-1, -2 and other relevant standards. The difference between the four testing methods was compared and analyzed. The results suggest that R-on-1 test obtains the highest LIDT, then comes the raster scan and 1-on-1, and the S-on-1 gives the lowest. The laser cumulative effect under 1000 pulses is not obvious, and the correlation between LIDT and spot size has not been observed when the difference of laser spot sizes is small. The influence of scanning interval and scanning fluence steps on laser conditioning effect was also discussed. Smaller interval produces better effect for the same spot size.