Pressure-controlled terahertz filter based on 1D photonic crystal with a defective semiconductor

The tunable terahertz (THz) filter has been designed and studied, which is composed of 1D photonic crystal (PC) containing a defect layer of semiconductor GaAs. The analytical solution of 1D defective PC (1DDPC) is deduced based on the transfer matrix method, and the electromagnetic plane wave numerical simulation of this 1DDPC is performed by using the finite element method. The calculated and simulated results have confirmed that the filtering transmittance of this 1DDPC in symmetric structure of air/(Si/SiO₂)^N/GaAs/(SiO₂/Si)^N/air is far higher than in asymmetric structure of air/(Si/SiO₂)^N/GaAs/(Si/SiO₂)^N/air, where the filtering frequency can be tuned by the external pressure. It can provide a feasible route to design the external pressure-controlled THz filter based on 1DPC with a defective semiconductor.