LAUSR

Abstract A novel configuration of MIM square ring resonator loaded with an array of silver nano-dots is proposed and investigated using the finite element method. The spectral characteristics of the resonator are studied in detail by varying the geometric parameters and material of the inner space of the ring. The sensitivity of the proposed design is enhanced by arranging the array of nano-dots periodically in the cavity which forms a grating and intensifies the SPPs at the boundaries of the dots. As a result, the interaction between SPPs and the surrounding medium is enhanced. The sensitivity of the device can be improved by increasing the number and size of the nano-dots. The maximum sensitivity of standard square ring resonator is 930 nm/RIU. Whereas our proposed design containing 21 nano-dots of 3 nm radius on each side of the cavity can offer a maximum sensitivity up to 1240 nm/RIU. Moreover, our proposed sensor design has FOM and Q-factor of 20 and 20.9 which is better than the standard square ring resonator, respectively. We believe that our findings are valuable for the compact and high sensitive sensors and may advance the integration level of the integrated optical circuits.