Analysis of Phase Modulation Performance in Metasurface Diffusers with Designed Complex Amplitude Transmittance

Metasurface diffusers (MDs) represent a promising technology for optical diffusion, offering a viable solution to the limitations of conventional optical diffusers [1]. Although conventional optical diffusers, such as frosted glass, are capable of controlling the overall diffusion spectrum, they lack the ability to precisely design transmitted phase distributions. In contrast, MDs, consisting of subwavelength-scale metaatoms, enable tailored phase modulation by manipulating the structure and material of the metasurface. However, the phase modulation capability of MDs is not exempt from limitations. This study evaluates the phase consistency of MDs designed using Gaussian-profiled optical diffuser models, focusing specifically on their ability to replicate the target phase distributions across varying thicknesses. Unlike prior designs that emphasised far-field speckle control, this study highlights the ability of MDs in achieving precise phase modulation, strong computational compatibility, and seamless integration into advanced optical systems.