Omnidirectional optical filtering based on two kinds of photonic band gaps with different angle-dependent properties

Edge states in heterostructures composed of two kinds of all-dielectric one-dimensional photonic crystals (1DPCs) can be utilized for narrowband filtering. However, the filtering transmittance peak, along with the photonic band gaps (PBGs) of all-dielectric 1DPC, will shift toward short wavelengths (blueshift) as the incident angle increases. In this letter, we investigate the filtering property of the heterostructure composed of an all-dielectric 1DPC and a 1DPC containing hyperbolic metamaterials (HMMs). For the 1DPC containing HMMs, the PBG can be designed to be redshifted under TM polarization. Based on these two kinds of PBGs with different angle-dependent properties, omnidirectional filtering at a fixed wavelength range can be realized under TM polarization. This omnidirectional filter can be utilized for all-angle phase matching in coherent nonlinear optical process and angle-insensitive Rabi splitting. Copyright (C) EPLA, 2020