High performance tri-band terahertz refractive index sensor based on cavity resonance and Tamm plasmonic modes

In this paper, a novel terahertz refractive index sensor consisting of two asymmetric distributed Bragg reflectors (DBRs) attached to graphene in the cavity, is proposed. Based on finite difference time domain simulation, Tamm plasmon polariton mode excited at the interface between the DBR and the graphene is coupled with the resonance modes of the cavity, which helps to improve the sensing performance. In its reflection spectra, there are three dips with the bandwidths of 1.82, 3.95 and 3.86 GHz at 1.04 THz, 3.00 THz and 3.13 THz after simulation optimization. And the corresponding sensitivities and the figure of merit can achieve 1.02, 2.58, 3.00 THz/RIU, and 559.34, 652.15, 776.17 RIU-1, respectively. Due to its high sensing performance and simple structure, the tri-band sensor may pave the way for the research on the detection of multimodal microscale analytes.

Automated summary

In this paper, a novel terahertz refractive index sensor consisting of two asymmetric distributed Bragg reflectors (DBRs) attached to graphene in the cavity is proposed. Finite difference time domain simulation shows that Tamm plasmon polariton mode excited at the interface between the DBR and the graphene is coupled with the resonance modes of the cavity, leading to improved sensing performance. The optimized reflection spectra exhibit three dips at 1.04 THz, 3.00 THz, and 3.13 THz, with bandwidths of 1.82 GHz, 3.95 GHz, and 3.86 GHz respectively. The corresponding sensitivities and figure of merit are 1.02, 2.58, 3.00 THz/RIU and 559.34, 652.15, 776.17 RIU-1. The tri-band sensor, with its high sensing performance and simple structure, may open up new possibilities for detecting multimodal microscale analytes.