Sensitivity optimization of a photonic crystal ring resonator for gas sensing applications

In this work we report on a computational study regarding the enhancement of the absorption of mid infrared (MIR) light for gas sensing applications. In order to address this goal, a photonic crystal ring resonator (PCRR) with a quality factor of more than 3.85 × 105 was designed. The considered PCRR is based on 2D pillar type photonic crystals, which consist of a hexagonal array of silicon rods. The high quality factor of the cavity, along with strong overlap between the field of the resonant mode and the analyte (0.76) and low group velocity of PCRR modes consequence into enhance sensitivity for gas sensing.