Dynamically tunable Fano resonance with high Q factor based on asymmetric Dirac semimetal split-ring structure

Abstract

Abstract We propose an asymmetric split-ring (ASR) structure based on Dirac semimetal, which has Fano resonance with a high quality (Q) factor in the terahertz (THz) band, the Q factor can reach a maximum value of 20.19. Amplitude modulation can be achieved by increasing the degree of asymmetry Δθ of the asymmetric split ring. As a result, in this study, an amplitude modulation of 27.19% has been achieved by increasing the asymmetry from 10° to 40°. Furthermore, our full-wave electromagnetic simulations show that the frequency sensitivity values of Fano and quadrupole resonance are as high as 0.6 THz/refractive index unit (RIU) and 0.933 THz/RIU, respectively. In addition, the sensing range can be adjusted by changing the Fermi levels of Dirac semimetal. Our study can guide the practical application of ultrasensitive THz sensors.