A D-Shaped Photonic Crystal Fiber Refractive Index Sensor Coated with Graphene and Zinc Oxide

Abstract

A surface plasmon resonance (SPR) sensor based on a D-shaped photonic crystal fiber (PCF) with an uncomplicated structure is proposed to detect the change of refractive index of liquid analytes, and numerical simulation is carried out by the finite element method (FEM). Using silver as the plasmonic metal, the performances of the SPR-PCF sensor coated with a graphene layer and zinc oxide (ZnO) layer were assessed. The sensor designed is only coated with material on the polished surface, which makes the sensor production uncomplicated and solves the problems of filling material in the hole and coating on the hole wall. The effects of structural parameters such as graphene layer thickness, silver layer thickness, ZnO thickness, lattice spacing and manufacturing tolerance of blowhole diameter on the sensor performance were numerically simulated. The numerical results show that the sensitivity of the SPR-PCF sensor coated with 25 nm ZnO is highest in the ZnO thickness range from 10 to 25 nm. In the refractive index range of 1.37–1.41 for liquid analyte, the maximum sensitivity and corresponding resolution reach 6000 nm/RIU and 1.667 × 10−5, respectively. In addition, the sensor has good stability and high structural tolerance under the tolerance of ±5% of blowhole diameter. This work has wide application value in the detection of biochemical analytes, water pollution monitoring, food quality, and medical diagnosis.

Optical Fibre-Based Sensors—An Assessment of Current Innovations

“…To detect variations in the refractive index of liquid analytes, an SPR sensor based on a D-shaped PCF is presented in [ 113 ]. The numerical simulation was performed using the finite element method (FEM).…”

Silver-TiO2 coated D-shaped photonic crystal fiber based SPR sensor for ultrasensitive refractive index detection: design and FEM analysis

“…A high-performance sensor for liquid analytes was developed by Liang et al, using a D-shaped PCF The sensor employed the plasmonic properties of silver and incorporated additional layers of graphene and ZnO to enhance its performance. The sensor was able to detect RI changes within a specific range of 1.37 to 1.41 with a remarkable sensitivity of 6000 nm RIU −1 [33]. Li et al, designed a D-shaped PCF based SPR sensor for RI measurement.…”

High sensitivity concave-shaped photonic crystal fiber sensor based on surface plasmon resonance

“…Meng designed a D-shaped PCF-SPR sensor with double loss peaks, exhibiting a high sensitivity of 18 900 nm/RIU in the sensing range of 1.35-1.38 [15]. From the sensors aforementioned, most PCF-SPR sensors are mainly applied to sensing of RIs above 1.33 [16][17][18]. While the applications for low RI detection are relatively rare, which could be used to detect analytes with RIs below 1.30, such as liquid CO 2 , medical oxygen, and sevoflurane [19].…”