Optical Response of Two-Dimensional Photonic Crystal on Metal

Abstract

Optical transmission properties of two-dimensional photonic crystals of a low refractive index material formed on a metal substrate have been theoretically investigated. The metal-base two-dimensional photonic structure is promising for low-cost fabrication and easy manipulation. We proposed a theoretical model of two-dimensional photonic crystal with the refractive index of n = 1.5 formed on a Ag substrate and calculated the optical transmission spectrum by using the finite difference time domain (FDTD) method. The calculated transmission spectrum shows an obvious photonic band gap even for the photonic crystal contacting to the metal substrate. We introduced a line defect cavity, and it has been clarified that the calculated Q factor increases with the refractive index. These results indicate that metal-base two-dimensional photonic crystal with the low refractive index can be widely applicable for photonic devices.