tunable terahertz narrow-band plasmonic filter based on optical tamm plasmon in dual-section insb slot waveguide

A novel narrow-band plasmonic filter in terahertz (thz) region based on optical tamm plasmon (otp) in dual-section insb slot waveguide is proposed, and the corresponding transmission characteristics are investigated. this filter consists of two insb layers and two insulator layer sections separated by an insb film. each insulator layer section contains three insulator periodic units structured by alternately two insulators with different refractive indices. in the filter, due to the otp is considered as a confined electromagnetic mode which exists at the boundary between two medium with high reflection, an otp wave could be formed on the insb-insulator interfaces and confined in the waveguide. thus, a narrow-band transmission peak with 3 db bandwidth of 0.017 thz in thz region around 0.54 thz is investigated by using the finite-difference time-domain (fdtd) method. moreover, since the permittivity of insb can be modified by varying the temperature, the performance of proposed plasmonic filter could be controlled by thermal tuning. therefore, excellent tunable narrow-band filtering performance is obtained.