Effect of SiO_2 barrier layer on laser induced damage threshold of second harmonic antireflection coatings on LiB_3O_5 crystal
Two different kinds of second harmonic antireflection(AR) coatings,with and without SiO2 barrier layer were prepared with ion assisted deposition on LiB3O5 crystal.Laser induced damage threshold(LIDT) by multiple-shot irradiation at 1 064 nm was studied and two typical damage morphologies were observed by SEM.The AR coatings with SiO2 barrier layer have an excellent LIDT,which is about 40% higher than that of coatings without barrier layer.The mechanism of LIDT enhancement by adding SiO2 barrier layer is also discussed.