Modelling the Light Scattering Behavior of Transmission-Mode GaAs Photocathode Under the AlGaAs Window Layer Rough Surface

To improve the understanding of the optical image resolution of transmission-mode GaAs photocathode, by establishing the surface scattering analysis model of AlGaAs window layer, we have researched the effect of the surface height distribution variance σ on scattering surface transfer function (STF) and point spread function (PSF) of transmission-mode GaAs photocathode. The simulation results show that the decrease of surface height distribution variance σ is beneficial to improve the optical image resolution. This improvement is mainly attributed to the decrease in input light energy attenuation and spatial diffusion caused by smaller surface height distribution variance σ, and thus the signal to noise ratio of scattering degraded optical image is increased.