Plasmonic nano bow‐tie arrays with enhanced LSPR refractive index sensing

Abstract

In this work, the performance of the nano bow‐tie arrays for biosensing applications has been investigated. Since the geometrical parameters of the device such as the bow‐tie length and gap size have major effects on the system's optical response, a parametric study based on finite‐difference time‐domain (FDTD) method has been conducted. In order to enhance the sensitivity, two bow‐tie shaped nanoparticles in the form of 2 × 1 and 2 × 2 arrays have been developed. In the case of TM polarisation, a sensitivity up to 923 nm/RIU with a figure of merit (FOM) of 5.5 has been obtained for 2 × 2 nano bow‐tie array. Moreover, the performance of the proposed nanoparticles for TE polarisation has been evaluated and a FOM exceeding 15.9 has been achieved for single nano bow‐tie. According to this study, the proposed nano bow‐tie structures have a great potential for sensing and detection applications.