Beam splitting and unidirectional cloaking using anisotropic zero-index photonic crystals

Abstract

We propose an anisotropic photonic crystal (PC) structure with close-to-zero effective parameters. The anisotropic zero-index property of PCs provides complex iso-frequency contours, where their shapes can change from ellipses or hyperbolae to a linear crossing. A mechanism of light beam splitting can be achieved by utilizing the linear crossing shaped iso-frequency curve. The manipulation of light beam propagations is verified by both numerical simulations and microwave experiments. By using pure dielectrics and scaling down to optical wavelengths, we also propose a design of nonperiodic PC structures to achieve optical unidirectional cloaking without size or shape limitation. Our design provides a promising platform for cloaking applications in the optical regime.