Terahertz Localization and Filtering Effects in Two-Dimensional Disordered Scattering Structures

In this work, we investigate photon localization and filtering effects in disordered scattering structures which might be used for future on-chip terahertz integrated systems. Through a reverse-design platform based on a discrete binary particle swarm optimization (BPSO) algorithm, a 2-D periodic dielectric cylindrical photonic crystal was transformed into a disordered scattering structure. Appropriate objective and figure of merit (FOM) functions are defined in order to achieve terahertz filtering function based on Anderson localization. The filters are in the bandgap range of 0.177–0.303 THz, with a FWHM bandwidth of 0.01 THz. We found that photon localization in disordered scattering structures is caused by coupling and resonance between adjacent microcavities.