A novel hollow core terahertz refractometric sensor

A novel hollow core photonic crystal fiber (PCF) based on Zeonex is proposed for sensing in the terahertz frequency range. A high level of asymmetry is introduced in the cladding by using a brick-like structure with identical square shaped air cavities. By filling the core with analytes of different refractive indices, the sensing characteristics of the fiber are numerically investigated using the finite element method (FEM) based COMSOL v5.3 software. The simulation results show that the proposed PCF displays a sensitivity as high as 98.9% and a minimum confinement loss of 5.5 x 10(-10) cm(-1) at an operating frequency of 2 THz. In addition, the fiber also shows ultra-low effective material loss (EML), high birefringence, large modal effective area and high numerical aperture at the optimum design conditions. The practical implementation of the fiber using different fabrication technologies is also discussed in detail. The excellent sensing performance and the design simplicity of the proposed PCF makes it highly suitable for use as a chemical sensor in different industrial and medical sectors.