Analogy of polarization-independent, multi-band and tunable electromagnetically induced transparency with high sensitivity based on simple circular ring resonators and vanadium dioxide film

Abstract

An analogy of polarization-independent, multi-band and tunable electromagnetically induced transparency (EIT) effect is proposed based on simple combination of circular ring resonators and vanadium dioxide film. The EIT-like effect is generated by bright-bright coupling resulting from adjacent ring resonators. High sensitivity up to 1.60 THz/RIU to the environmental refractive index is achieved utilizing the transparency peak. Accompanying with the EIT-like effect, the multi-band slow light phenomenon is obtained around the transparency windows. In addition, by inducing the insulator-metallic transition of the vanadium dioxide layer, the EIT-like curves can be actively manipulated while the multiple modulation is realized without refabricating the structure. Particularly, due to structural symmetry, the EIT-like windows keep unchanged and maintain noticeable with various polarization angles. The proposed structure has potential applications such as terahertz sensors, slow-light devices and modulators.