Theoretical design of a 2D photonic crystal resonator highly sensitive for temperature sensing

This paper proposes a two-dimensional photonic crystal ring resonator for temperature sensing. The sensor structure is based on a hexagonal array of silicon (Si) rods surrounded by air. Its size is 11.5 × 10 μm in X and Z directions, respectively. The detection principle is based on the change of the refractive index of silicon. This variation is due to the change of the applied temperature and shifts in the resonance wavelengths. The finite difference time domain and plane wave expansion methods were used to simulate the light transmission for different temperatures and photonic band gaps. The proposed sensor has a significant performance, a sensitivity of 935 nm/RIU, a calculated quality factor of 135, a merit factor equivalent to 81 RIU−1, and a detection limit of 1.24 × 10–3 RIU. The results are very interesting and show that the sensor is reliable, very compact, and can be integrated into various applications of transduction and detection.