Filter performance of reduced sized defect photonic crystals based on single‐negative materials

Single‐ and multiple‐channeled filters based on single‐negative (SNG) photonic crystals with inversion defects have been demonstrated theoretically. Omnidirectional filters with wide angular apertures and multiple‐channeled filters at normal incidence have been reported. Sharp, high transmission peaks with frequencies lying within the SNG range are obtained. By variation of the structural parameters these structures can also be made to function as tunable or polarizing filters, though the frequencies of the transmission modes in these two cases will lie outside the SNG range. A significant feature of all the filter types discussed is the drastic reduction in size of the proposed structures in comparison to those reported earlier. This implies easier fabrication methods and lower cost. Improved performance of devices has been achieved by proper placement of defects.