Nanoslotted microring resonator for high figure of merit refractive index sensing

Abstract

A nanoslotted microring resonator (NSMR) with enhanced light-matter interaction has been designed, which can be used for high sensitive refractive index sensing. The performance of the device is investigated theoretically based on a three-dimensional finite-difference time-domain (3D-FDTD) method. In order to achieve high figure of merit sensing, the nanoslot geometry is exploited to make the optical field strongly localized inside the low index region and overlap sufficiently with the analytes. By using the 3D-FDTD method, the proposed NSMR sensor device achieves a high Q-factor (Q > 105) and sensitivity ~100 nm/RIU (RIU – refractive index unit). Moreover, the strong light confinement introduced by the nanoslot in NSMR results in the sensor figure of merit as high as 6.73 × 103. Thus, the design we proposed is a promising platform for refractive index-based biochemical sensing and lab-on-a-chip applications.