Ultrasensitive and Tunable Sensor Based on Plasmon-Induced Transparency in a Black Phosphorus Metasurface

We propose an ultrasensitive and tunable mid-infrared sensor based on plasmon-induced transparency (PIT) in a monolayer black phosphorus metasurface. Results show that there are two PIT windows, each of which occurs when the long axis of the metasurface is placed along the MBP's armchair and zigzag crystal directions, respectively. The corresponding sensors based on these PIT effects show high sensitivities of 7.62 THz/RIU and 7.36 THz/RIU. Both PIT frequencies can be tuned statically by varying the geometric parameters or dynamically by changing the electron doping of monolayer black phosphorus, making the sensors adaptable to tackle with a variety of scenarios. We expect that this work will advance the engineering of metasurfaces based on monolayer black phosphorus and promote their sensing applications.