Graded wavelike two-dimensional photonic crystal made of thin films.

A filling-factor-graded wavelike two-dimensional photonic crystal (2DPC) possessing a light-path bending effect that is polarization dependent is theoretically studied by using a qualitative analysis of the isofrequency curves. The numerical simulation results obtained by using the finite-difference time-domain method demonstrate that such a graded 2DPC has potential applications in a polarization splitter and a parallel-plane resonant cavity. A new kind of waveguide structure that combines a filling-factor-graded wavelike 2DPC and one-dimensional multilayer thin films is also discussed.