Slow light effect based on tunable plasmon-induced transparency of monolayer black phosphorus

Black phosphorus (BP) is a novel plasmonic materials at the infrared and terahertz regions. We have theoretically investigated the anisotropic of in-plane monolayer BP in terms of conductivity. We have designed a periodic structure for a special shape and achieved an obvious plasmon-induced transparency phenomenon. The results of finite difference time domain simulation and coupled mode theory are in consistent good agreement. It is found that the bandwidth of plasmon-induced transparency phenomenon window can be effectively adjusted by changing the shape of the BP structure. Since the structure of the monolayer BP is completely continuous, it is easy to change the carrier density to adjust its resonance intensity and resonance frequency, which basically ensures the tunability of the plasmon-induced transparency phenomenon. This structure has an excellent slow light effect, and the maximum group index of this structure is 112. This research may open new doors for the application of monolayer BP in transmission modulation, especially for the modulation of slow light device.