Investigation Effects of Filling Rate on the Bands Gaps of Two Dimensional Photonic Crystals

The influences of the filling rate on the photonic band gap properties of the two dimensional hex photonic crystals are investigated using the finite-difference time-domain method. When the filling rate f varies from 0.227 to 0.735 reminding the refractive index as 5, the number of the photonic band gaps decreases from 5 to 2 bands, the width of the photonic band gap between the transmit peaks become narrow; but for larger f > 0.445, the transmit intensity is very low in the high frequency region, it can be consider as a larger photonic band gap region, the onset of this larger photonic band gap shifts toward low frequency. At the same time, the onset transmit peaks shift toward low frequency also. The simulation results show that the photonic band gap can be effectively changed by the filling rate.