Abstract:
Photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensors have a
unique sensing capability and can be applied over a wide refractive index (RI) range. In
this research work a simple yet highly sensitive multi-channel hexagonal PCF based SPR
RI sensor for detecting multiple analytes has been put forwarded. The target analytes and
the plasmonic materials, such as, gold (Au), Au with Tantalum Pentoxide (TaO) and
Au with Titanium Dioxide (TiO) are employed around the exterior of the sensor for the
feasibility of the operation. Twelve circular air-holes in two layers constitute the PCF
structure which makes the fabrication process easy and realizable. Numerical
investigations are carried out employing a full-vector finite element method (FEM) of
COMSOL Multiphysics to obtain the sensing performance of the PCF-SPR structure.
After optimizing the structural parameters, the sensor achieves maximum wavelength
sensitivity (WS) of 38100 and 21600 nm/RIU, for channels-1 and 2, respectively. For
channel-3, the sensor achieves a maximum WS of 45800 nm/RIU. To the best of our
knowledge, the proposed sensor achieves better performance in terms of wavelength
sensitivity, wavelength resolution, amplitude sensitivity, amplitude resolution, figure of
merit, etc., compared to the existing literature. Overall, the sensor achieves RI range of
1.36 to 1.42 and within which many analytes samples fall. As a specific application, this
multi-channel sensor may be employed to detect cancerous cells. In the case of cancerous
cell detection, the proposed sensor achieves maximum WS and amplitude sensitivity of
12000 nm/RIU and -2440.30 RIU, respectively, for HeLa cells. It is envisaged that the
proposed sensor has a high potential to detect unknown RI for different chemical and
biomedical applications due to its superior performance, simple design, and multi-analyte
detection ability.
