Design and Simulation of a New Highly Sensitive Gas Sensor Based on Negative Refraction Photonic Crystal

In this paper, design and simulation of a new highly sensitive gas sensor based on a hybrid photonic crystal (PC) structure, containing negative and positive refractive index sections, is presented. It has been shown that using a PC with negative refraction in the first section, the transmitted power is concentrated on the entrance of the sensing channel, and the transmission of the proposed sensor will be increased. Based on the two dimensional finite-difference time-domain (2D FDTD) simulation results, the sensitivity and the transmission of the proposed sensor are measured as 876  nm/RIU and 0.7, respectively. The modified structure, which is applicable for the gas sensing, is made using the creation of a single cavity in the center of the sensing channel. In modified structure, the sensitivity, the transmission and quality factor are measured as 880 nm/RIU, 0.6 and 3920, respectively. The simulation results show that the modified structure could well be used in the gas sensing applications.