Pump-tuned plasmon-induced transparency for sensing and switching applications

A novel implementation for plasmon-induced transparency (PIT) is investigated theoretically and numerically. The structure is composed of a bus waveguide coupled to a nanodisk and two internally tangent disks (TITD). It is shown that the PIT peak can be tuned from 782 to 815 nm using an external pump laser with an intensity of up to 24.39 MW/cm2 (power ≅2mW). The wavelength, transmission and width of the PIT peak can be adjusted by changing the nanodisk-TITD gap and the radius of the internal disk. The proposed structure can be well employed as a nanosensor, with a refractive index sensitivity and figure of merit equal to 690 nm RIU−1 and 49.28 RIU−1 respectively. In addition, the operation of a plasmonic switch based on the proposed structure is investigated. The switch demonstrates a good modulation depth (up to 20 dB), increasing almost monotonically with an increase of the pump intensity in the range of 0-28 MW/cm2.