Influence of Ag Thin Films on Surface Roughness and Light Scattering of Optical Substrate
银薄膜对光学基底表面粗糙度及光散射的影响

In order to investigate the relationship of Ag thin films and optical substrate surface roughness and light scattering,a new method was presented,of which total reflectance scattering was obtained by integrating vector light scattering expression,bidirectional reflectance distribution function(BRDF),at interfaces roughness perfectly correlated and completely uncorrelated model respectively.Total reflectance scattering and BRDF of Ag thin films on optical substrates were calculated at different thickness of Ag thin films for these two theoretical models.The results of theoretical calculation show that when the thickness of Ag thin films deposited on optical substrate is thicker than 80nm,total reflectance scattering of Ag thin films equate to total integrated scattering.This time Ag thin films can perfectly replicate surface profile of optical substrate.And,experiments of different Ag thin films deposited on identical surface root mean square roughness were carried on.The results show that the thickness of Ag thin films is at 80~160 nm,and Ag thin films can perfectly replicate substrate roughness profile.