Characterization of a High-performance PCF-SPR Sensor for Biomedical Applications

Abstract

Background: Surface plasmon resonance (SPR) based fibre optic sensors are becoming increasingly popular in biomedical applications. However, the sensor performance is degraded because of low sensitivity with inadequate detection accuracy and figure of merit. Objectives: The first objective of this study is to design a D-shaped photonic crystal fibre (PCF) using COMSOL multiphysics. The second objective is to enhance the performance of the designed sensor in terms of sensitivity and detection accuracy using single and dual metal layer structures. In addition, the performance of the proposed sensor is compared with the existing one. Methods: In this study, the performance of the PCF-SPR sensor is improved using a D-shaped photonic crystal fibre (PCF) and two metals as grating layers. The work in this paper is divided into two parts. In the first part, the gold metal layer with optimized thickness is used to achieve good sensitivity. In the second part, the combination of gold and silver dual metal layers with optimized thickness is used to achieve good detection accuracy. Moreover, the performance of the proposed sensor is compared to other published D-shaped PCF sensors. Results: The proposed D-shaped PCF-SPR sensor is designed and simulated using COMSOL multiphysics. The results in terms of sensitivity (S) and detection accuracy (DA) are obtained using a single metal layer and dual metal layers with optimum thickness. Moreover, the transmission coefficient and loss curve have been calculated using different refractive indices of the material. In addition, the simulation results are validated for cancer detection using the proposed sensor. Conclusion: An improvement of the D-shaped PCF sensor for cancer detection is presented in terms of S and DA using single or dual metal layer structures and COMSOL multiphysics. In a single metal layer structure, only gold is used as a grating layer, and the thickness of the grating layer is optimized for achieving high sensitivity. Similarly, a combination of gold and silver is used as the grating layer in the dual metal layer structure for achieving a high DA. Moreover, the obtained results of the proposed PCFSPR sensor are compared with the published results and found that the proposed sensor can be used with a high degree of S and DA for biomedical applications and also can be used in the bio-sensing field.