Enhancing Gas Sensing Performance with 2D Material-Integrated Sub-Wavelength Grating Micro-Ring Resonator: Improved Sensitivity and Selective Detection

Silicon photonics devices are widely utilized in optical gas sensing owing to their compact size and compatibility with CMOS technology. However, their limited sensitivity hampers their versatility. In this study, we introduce a highly sensitive gas sensor incorporating a 2D material gas-absorbing layer and a sub-wavelength grating (SWG) micro-ring resonator. Leveraging the large surface-volume ratio of the 2D material layer, it efficiently absorbs gas molecules and induces substantial refractive index changes during sensing. Finite-Difference Time-Domain (FDTD) simulation results will be showcased which demonstrate enhancement in both bulk sensitivity and surface sensitivity upon incorporating the 2D material layer. Moreover, the SWG design enables a larger evanescent field-analyte interaction region, resulting in an elevated quality factor for the proposed sensor. Furthermore, by coating the micro-ring resonators with different 2D materials, we envision highly selective sensor architectures.