Narrow band and angle-insensitive filter based on one-dimensional photonic crystal containing graded-index defect

Abstract

Using finite difference time domain (FDTD) method, we numerically investigate one-dimensional photonic crystals (1D PCs) with [Formula: see text] structure, where [Formula: see text] and [Formula: see text] stand for different dielectric materials, and [Formula: see text] the graded-index (GRIN) material. The transmission properties of the multilayer structure have been studied, and the results show that a tunable narrow band-pass filter (BPF) can be obtained by changing gradient coefficients of the GRIN defect layer. For an increasing incident angle, although the transmittance becomes smaller, positions of the resonant peak remain the same, which can act as the angle-insensitive filter.