Laser-conditioning on multilayer dielectric gratings

Laser-conditioning on multilayer dielectric gratings(MDGs) is investigated with the standard N-on-1 test method. It is found that the laser induced damage threshold(LIDT) of MDGs is increased up to 2.0 times the value without laser-conditioning. The possible physical mechanism can be explained by the reduction of contamination and surface roughness in the grating region under the irradiation of laser with low energy. In addition to the existing methods such as grating structure optimization and acid-cleaning, laser-conditioning could be an alternative way to improve the LIDT of MDGs.