利用时域有限差分方法理论研究了由介质锗柱组成的二维三角晶格光子晶体的完全光子禁带。研究表明,对于由圆形空心锗柱排列在空气中组成的三角晶格光子晶体,TM偏振和TE偏振的光子禁带存在重叠,因而具有完全禁带。当锗柱的形状为空心三角形时,可实现宽度为0.074 (2πc/a)的完全带隙,该带隙宽度达到了中心频率的16.2%。

Absolute band gaps of the two-dimensional triangular-lattice photonic crystals consisting of Ge rods are calculated with the finite-difference time-domain method. Through calculating the band structures of the triangular-lattice photonic crystal consisting of hollow circular Ge rods,it is found that the TM-polarized and TE-polarized photonic band gaps can be overlapped,and an absolute photonic band gap can be obtained. A large absolute band gap of 0.074 (2πc/a) can be obtained for the structures with a triangular lattice of hollow triangular Ge rods immersed in air,corresponding to 16.2% of the central frequency.