High sensitivity refractive index sensor based on triple layer MgF2-gold-MgF2 coated nano metal films photonic crystal fiber

Abstract

A high sensitivity triple layer photonic crystal fiber (PCF) refractive index (RI) sensor based on surface plasmon resonance (SPR) is proposed for RI analytes sensing. As a plasmonic material, a nanofilm gold layer with two MgF2 layers is used that assists to achieve high sensitivity, larger birefringence, maximum resolution and high transmittance profile. The entire analysis and sensing performance of this proposed structure is done by using the finite element method (FEM) for 1.7 µm to 3.7 µm wavelength. The highly SPR sensitive RI analytes are injected into the outmost air holes of the cladding where fused silica is served as the base material. The highest wavelength sensitivity response of 28,046.205 nm/RIU is obtained at RI analytes 1.38. The maximum resolution, birefringence and transmittance variance are 3.94 × 10−5 RIU, 3.59 × 10−4 and −45.80 dB respective in the RI analytes range 1.32–1.38. The outstanding sensing performance suggests the proposed triple layer PCF sensor as a promising candidate in the field of RI analyte sensing.