Revised plane wave method for dispersive material and its application to band structure calculations of photonic crystal slabs

In this letter we present a revised formulation of the plane wave method (PWM) for the band structure calculation of photonic crystals. In comparison to the conventional PWM, the formulation in this letter allows for modeling of dispersive material. One application of the presented method is for band structure calculations of photonic crystal slabs. While a thin photonic crystal slab is considered, a full three-dimensional (3D) problem can be reduced to a two-dimensional one by using the effective index method. However, the obtained effective index of such a slab is frequency dependent. The revised PWM is then applied to solve this problem. The results obtained using this algorithm have been compared with those using a full 3D finite-difference time-domain method and found to agree very well.