A semiconductor metasurface with multiple functionalities: A polarizing beam splitter with simultaneous focusing ability

Abstract

We propose a semiconductor metasurface that simultaneously performs two independent functions: focusing and polarization filtering. The wavefronts of the reflected and transmitted light distributions are precisely manipulated by spatial parametric variation of a subwavelength thin-film Si grating, which inherently possesses polarization filtering properties. We design a 12-mu m-wide metasurface containing only nineteen Si grating ridges. Under a 10-mu m-wide unpolarized Gaussian beam incidence at wavelength of 1.55 mu m, the resulting device shows promising theoretical performance with high power efficiency exceeding 80% and polarization extinction ratio of similar to 10 dB with focal spot diameters near 1-2 mu m.