Optical reflector and selective TM polarized optical filter in the infrared region using Si-based one-dimensional photonic crystal

The present communication deals with the transmission of electromagnetic waves through a one-dimensional photonic crystal based on Si/air multilayer system. The effect of the angle of incidence on transmission spectra of the proposed structure for TE and TM polarizations has been studied. For angle of incidence wavelengths 50°, the proposed structure works as a cent percent optical reflector for a certain range of wavelengths. For other angles of incidence more than 50°, the structure works as a selective TM-polarization filter i.e., a filter which completely blocks TE-polarized waves but allows certain wavelengths of TM-polarized waves. At the angles of incidence of 87°–89°, the structure can work as a single or multi-channel optical filter by varying the number of unit cells. Only for one unit cell, the structure can work as a single channel filter without introducing any defect in the geometry. Therefore, such types of structures are easier to fabricate and may be cost-effective as compared to defective one-dimensional photonic crystals.