中文说明：利用平面波展开法计算二维光子晶体的能带结构与带隙，超级详细。（The band structure and band gap of two-dimensional photonic crystals are calculated by plane wave expansion method.）
English Description：
The band structure and band gap of two-dimensional photonic crystal are calculated by plane wave expansion method. （The band structure and band gap of two-dimensional photonic crystals are calculated by plane wave expansion method.）