High‐Sensitivity Tunable Bloch Surface Waves’ Biosensor Using Nanocomposite Cap Layer

Abstract

The advantage of the high versatility of the nanocomposite (Nc) materials in modeling photonic structure devices is exploited to design an optical biosensor based on Bloch surface waves (BSWs) to probe different biomolecular species. The suggested biosensor is constituted by two periods of low and high refractive indices (RIs) of alternate dielectric materials SiO2 and TiO2 capped by Ag−TiO2 Nc layer operating under the Kretschmann configuration and using p‐polarized incident light. Herein, the biosensor performances are theoretically investigated in a wide range of the sensing medium RI [1.33, 1.61] using selected operating wavelengths 455, 465, 480, 500, and 600 nm to deviate a large dielectric loss of the Ag−TiO2 Nc layer. The results show that the structure sustains BSW for each wavelength in separate domains of the sensing medium RI conferring to the proposed biosensor a potential for the high‐sensitive multiwavelength detection of different biomolecular entities.