Theoretical and simulation study of dynamically tunable sensor based on liquid crystal-modulated Fano resonator in terahertz band

• Dynamically reconfigurable sensor based on liquid crystal-infiltrated Fano resonator in terahertz range. • Easily adjustable external voltage applied on the liquid crystal to realize tunability of the sensor. • Dynamical tunability of not only the operating band, but also the sensing range (in terms of refractive index) • Ultra-high sensitivity achieved at the same time, due to the Fano structure of the sensor. • Pretty flexible for sensing applications in terahertz range. A liquid crystal-modulated Fano resonator is designed, which has high sensitivity, tunable operating band and adjustable sensing range at the same time. The Fano resonator is constructed by attaching a ring above a main channel and connecting a groove beneath it. With the interaction of the discrete mode provided by the ring and the continuous mode provided by the groove, a Fano resonator can be produced with a pretty high sensitivity. Moreover, by infiltrating liquid crystals into the inner layer of the ring cavity, the resonant frequency of the Fano resonator can be shifted freely by adjusting the biasing voltage across the liquid crystals. The margin of the shifted frequency can achieve 57 GHz for the first-order resonance around 1.609 THz, and 140 GHz for the second-order resonance around 2.694 THz, respectively. Meanwhile, the liquid crystal infiltrated Fano resonator achieves a favorable sensitivity in terms of figure of merit (FOM) as high as 6.02 × 10 4 . The novel Fano resonator is pretty attractive for sensing applications that require high sensitivity, tunable operating band and adjustable sensing range at the same time, paving the way for developing flexible terahertz systems in the coming future.