Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer for LiB_3O_5 crystal

摘要

Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer were investigated for LiB_3O_5 (LBO) substrate. The design was based on the vector method. The thickness of the inserted SiO_2 interlayer could be changed in a wide range for the four-layer design with two zeros at 1064 and 532 nm. The coatings without any interlayer and with 0.1 quarter-wave (λ/4), 0.3 λ/4, 0.5 λ/4 SiO_2 interlayer were deposited respectively on LBO by using electron beam evaporation technique. All the prepared coatings with SiO_2 interlayer indicated satisfying optical behavior. This expanded our option for the thickness of an interlayer when coating on LBO substrate. The prepared films with SiO_2 interlayer showed better adhesion than that without any interlayer. The thickness of the interlayer affected the adhesion, the adhesion for the coating with 0.5 λ/4 SiO_2 interlayer was not as good as the other two.