Transmission properties in a one-dimensional finite extrinsic semiconductor InSb photonic crystal

The properties of wave transmission in a strongly dispersive semiconductor-dielectric photonic crystal (SDPC) are theoretically investigated. We consider a one-dimensional finite SDPC, air/(SD)^NS/air, where, N is the stack number, S is an extrinsic semiconductor, n-type InSb (n-InSb), and D is a dielectric layer of SiO₂. Transmission peaks can be found in the frequency region where the real part of the complex permittivity of n-InSb is negative. The number of peaks is equal to the stack number N. The positions of peaks can be tuned by the thicknesses of S and D. The peaks are seen to be blue-shifted as the doping density increases, leading to a tunable filter. The locations of peaks are also strongly dependent on the incidence angle, but weakly dependent on the polarization of the incident wave. The results suggest that a tunable multichannel filter can be achieved by using such an SDPC. Filters with tunable and multichannel features are of technical use in photonic applications such as in the optical electronics and communications.