Photonic crystal concentric dual-microring resonator for refractive index sensing

A high-performance photonic crystal (PhC) concentric dual-microring resonator (PhCCDMRR) for refractive index sensing is proposed in this paper. It confines the energy into PhC air holes to enhance the light-matter inter-action, and the increased modal area of the concentric rings improves the sensing sensitivity. The slow-light effect near the photonic bandgap results in a PhC waveguide with a maximum group index of 18.2. In the transmis-sion spectrum, a high extinction ratio of 22 dB is achieved. This sensor obtains a refractive index (RI) sensitivity of 265 nm/RIU (RI unit) using sodium chloride solution as samples, which has promising applications in RI sensing. (c) 2023 Optica Publishing Group