All-angle polarization insensitive cloaking in 2D photonic crystals

Abstract

In this article, a 2D hole-type square lattice photonic crystal is considered to achieve all-angle polarization insensitive cloaking using self-collimation phenomenon. The regarded structure is composed of air holes in a high dielectric background of PbTe (nPbTe˜6) and is applicable for Mid-IR range. The bandwidth achieved for the maximum deviation angle of self-collimation of 2o is Δω/ωc=0.55% corresponding to Δλ=22.6nm at central wavelength of λc=4.1175μm. The presented structure is capable of cloaking of any structure in any size and shape since the propagating wave is not interacting with the cloaking region. To reduce the reflections from interfaces an optimized one-layer antireflection has been designed to reduce the reflections caused due to index mismatch. The structure and its functionality have been investigated by the PWE and the FDTD methods.