Modelling and simulation of novel liquid‐infiltrated PCF biosensor in Terahertz frequencies

Abstract

The liquid‐infiltrated photonic crystal fibre (LI‐PCF) is proposed for guiding terahertz radiation. Geometrical asymmetry is achieved by introducing a large ellipse in the core. By filling the ellipse with liquid cocaine, the optical properties of the photonic crystal fibre (PCF) are theoretically examined using finite element method‐based COMSOL multiphysics software. At an operating frequency of 1 THz, the proposed LI‐PCF demonstrates a sensitivity of 87.02% and confinement loss in the order of 10 −4 cm −1 . The PCF also demonstrates extremely low effective material loss <0.01 cm −1 , a birefringence of 0.018, large effective mode area of 1.11 × 10 5 µm 2 , a high numerical aperture of 0.45 and near‐zero ultra‐flattened chromatic dispersion of 1.4351 ± 0.5883 ps/THz/cm. The design simplicity and high sensitivity, strong confinement factor, low material losses and high birefringence of the fibre suggest that the proposed fibre may be convenient for PCF‐based cocaine sensing, for application in the security and defence industries.