Al-doped ZnO based long range optical fibre sensor for efficient low refractive index detection

Abstract

In this article, a simulation of surface plasmon resonance (SPR) based Al-doped ZnO (AZO) coated long-range low refractive index detections in infrared range sensor by the finite element method is presented. Plasmonic material Al-doped ZnO is used for SPR conditions in the desired range. The effects of AZO layer thickness on resonance wavelength, confinement loss, and sensitivity of the proposed sensor are examined for different analyte refractive indices. We have optimized coated AZO layer thickness of 90 nm and width of 124.70 µm in our work. The proposed infrared sensor has achieved refractive index sensitivity 2000–16,000 nm/RIU, and the resolution 5.00×10-5-6.25×10-6RIU for the analyte’s refractive index range from 1.23 to 1.37. The proposed sensor may be utilized for detecting low refractive index organic chemicals, biomedical, and liquid foods and may also be used in other sensing applications.