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

Abstract

In this article, 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 (FEM) is presented. Plasmonic material Al-doped ZnO used for SPR condition in the desired range. The effect of thickness of the AZO layers on resonance wavelength, confinement loss, and sensitivity of the proposed sensor has been examined for different analyte refractive index. These parameters do not change with AZO layers width variation. We have optimized coated AZO layer thickness 90 nm and width 124.70 µm in our work. The proposed infrared sensor has achieved refractive index sensitivity 2000-16000 nm/RIU and resolution 5.00 × 10 −5 − 6.25 × 10 −6 𝑅𝐼𝑈 for refractive index of analyte range from 1.23 to 1.37. The proposed sensor is useful for detection of low refractive index organic chemical, biomedical, liquid foods and may be used other analyte sensing applications.