Design of refractive index sensing based on 2D PhC air-slot width-modulated line-defect microcavity

Abstract

In this paper, we propose an investigated sensor array based on two-dimensional photonic crystal air-slot width-modulated line-defect microcavity. This sensor consists of a waveguide coupled with microcavity. To achieve a high quality factor, we have tuned some parameters of the microcavity. The principle of sensing is based on the resonance wavelength shift when the refractive index is changed. For sensitivity analysis, we proposed various conventional designs (A–D). We demonstrated that the design D has the highest sensitivity. An air-slot is created within the line-defect. The existence of the slots enhances the light-matter interactions. The simulation results are obtained by using finite-deference time-domain method. The sensitivity can achieve 400 nm/RIU, with detection limit of 2.98 × 10−5 RIU.