Design of Double Ring Label-Free Terahertz Sensor

Field confinement is the main factor in designing sensitive label-free sensors, which are based on the refractive index change. In our proposed structure, the deformation of the normal double waveguide mode into confined supermodes in the case the waveguide is curved into a small ring is exploited to increase the sensitivity of the sensor. The design procedure of a terahertz sensor based on refractive index is presented here. Important factors such as quality factor, sensitivity, and figure of merit (FOM = 62.81) are calculated, which show good improvement in comparison to other integrated terahertz sensors.