Generation of partially coherent beams with special correlation structures based on polarization-independent statistical metasurfaces.

In this paper, we study the modulation of the optical field's spatial coherence by using a polarization-independent metasurface model composed of Si cylinders. Based on the waveguide-phase principle, the cylinders' radii and height are optimized to obtain a nearly linear phase variation of 2. The statistical metasurface is constructed by using a series of metasurface patterns according to the theoretical phase distribution of the partially coherent beam with a specified degree of coherence or correlation structure. We numerically demonstrated the generation of four typical partially coherent beams with special correlation structures, i.e., the Hermite-Gaussian correlated Schell-model beam, the rectangular cosine-Gaussian Schell-model beam, the elliptical Laguerre-Gaussian correlated Schell-model beam, and the rectangular multi-Gaussian correlated Schell-model beam based on different statistical metasurfaces constructed by 100 patterns. These polarization-independent statistical metasurfaces operate with arbitrary linearly polarized or unpolarized light and can effectively simplify the setup and provide a more economical approach for the generation of partially coherent light applied in beam shaping, laser communication, optical imaging, and so on.