title: Study of HfO2/SiO2 dichroic laser mirrors with refractive index inhomogeneity.
abstract: HfO2/SiO2 dichroic mirrors, having high reflectance at 1064 nm and high transmittance at 532 nm, play an important role in high-power laser systems. However, the half-wave hole effect, caused mainly by the refractive index inhomogeneity of hafnia, affects the spectra and application of these mirrors. Two approaches to eliminate the half-wave hole effect have been proposed. Both approaches attempt to shift the location of the half-wave hole in comparison with the original wavelength. One approach broadens the reflectance band of the first harmonic wavelength and simultaneously adjusts the central reflectance band to a longer wavelength, whereas the other approach combines the two stacks to adjust the location of the half-wave hole far away from the wavelength of interest. Two kinds of dichroic mirrors have been successfully fabricated; moreover, it was found that the method of a two-stack combination, 0.9(HL)8 and 1.1(HL)8, provides designs that can be fabricated more easily and with better quality spectral characteristics.
authors: Hongfei
authors: H
authors: Jiao
authors: Xinbin
authors: X
authors: Cheng
authors: Ganghua
authors: G
authors: Bao
authors: Jin
authors: J
authors: Han
authors: Jinlong
authors: J
authors: Zhang
authors: Zhanshan
authors: Z
authors: Wang
authors: M
authors: M
authors: Trubetskov
authors: Alexander V
authors: AV
authors: Tikhonravov