A novel modulation mechanism in plasmon-induced transparency waveguide

We numerically studied the realization of plasmon-induced transparency (PIT) in an InSb waveguide coupled with two resonators of different lengths in the terahertz (THz) region. In the two different methods of the finite-difference time domain method (FDTD) and coupling mode theory (CMT), the physical mechanism of the PIT effect of the waveguide system is numerically simulated and theoretically analyzed. The results of numerical simulations and the theoretical calculations were found to be perfectly consistent. Most importantly, a novel modulation mechanism for the PIT effect is found in the waveguide. The conductivity of the photoactive silicon is controlled by adjusting the intensity of the pump light, thereby realizing the dynamic modulation of the PIT window. In addition, the resonance frequency of the PIT spectrum can be controlled by adjusting the coupling distance between the resonators or the temperature of the environment. This plasmonic waveguide system may have interesting potential applications for integrating optical circuits, such as optical switches, slow light components, and thermally tuned filters.