Modelling and simulation of novel liquid-infiltrated PCF biosensor in Terahertzfrequencies

Abstract

The liquid-infiltrated photonic crystal fibre (LI-PCF) is proposed for guiding terahertz radiation. Geometricalasymmetry is achieved by introducing a large ellipse in the core. By filling the ellipse with liquid cocaine, the optical properties ofthe 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 theorder of 10−4 cm−1. The PCF also demonstrates extremely low effective material loss <0.01 cm−1, a birefringence of 0.018, largeeffective mode area of 1.11 × 105 μm2, a high numerical aperture of 0.45 and near-zero ultra-flattened chromatic dispersion of1.4351 ± 0.5883 ps/THz/cm. The design simplicity and high sensitivity, strong confinement factor, low material losses and highbirefringence of the fibre suggest that the proposed fibre may be convenient for PCF-based cocaine sensing, for application inthe security and defence industries