Plasmon-induced transparency in sensing application with semicircle cavity waveguide

In this paper, a plasmonic nano-sensor is proposed in semicircle cavity waveguide, the transmission characteristics of the new structure are analyzed by the finite-difference time-domain method. Dual plasmon-induced transparency (PIT) phenomenon is emerged in the semicircle cavity coupled with bus waveguide, which is resulted from the destructive interference superposition of the reflected and transmitted waves from cavity resonator. High sensitivity and figure of merit (FOM) based on PIT in the resonator has been investigated in detail. The sensitivity of the proposed model is about 2000 nm/RIU and its maximum FOM is up to 85370. In addition, dual PIT peaks are found by changing the structure parameters. The simple structure with such high sensitivity and FOM provide potential implications in nano-sensing field.