Polarization-independent negative refraction effect in SiO2-GaAs annular photonic crystals

Abstract

We systematically investigated the negative refraction effect for both TM and TE polarization modes in SiO2-GaAs annular photonic crystals with triangular lattice. It was found that, in comparison with normal triangular-lattice air-holes photonic crystals, the annular photonic crystals have much lower and flatter band structures, which are quite beneficial to the formation of convex equifrequency surfaces for both polarizations. Further analyses on equifrequency surfaces and the electric field distribution of annular photonic crystals with different parameters have not only first demonstrated the possibility of polarization-independent negative refraction effect in annular photonic crystals, but also revealed some important laws to control the working frequency and performance of this remarkable effect.