Characteristics of a rectangular channel sensor based on evanescent field enhanced photonic crystal fiber

Abstract

A miniaturized, rectangular-channel photonic crystal fiber (RC-PCF) high-sensitivity sensing scheme is proposed for high-refractive-index liquid analysis. The designed PCF is polished and features an open rectangular channel in the upper-middle part of the fiber cross-section, which facilitates the efficient flow of the sample liquid. The design utilizes the merit of photonic crystal array and the operability of external sensing. Gold is chosen as the plasma material because of its chemical stability and biocompatibility in a liquid environment. To obtain high sensitivity, the effect of the sample liquid height in the channel on the sensing performance is investigated. Numerical results show that the maximum wavelength sensitivity and amplitude sensitivity of the sensor is 28,000 nm/RIU (refractive index unit) and − 1266.5 R I U − 1 with a liquid analyte height of 100% of the channel height. The maximum wavelength sensitivity increases from 28,000 to 42,000 nm/RIU when the gold film thickness decreases from 30 nm to 20 nm. Due to the sensor’s simple structure and high sensitivity, it will have potential applications in the detection of high-refractive-index samples in biology, medicine, and chemistry.