Design and analysis of photonic crystal fiber for waveguiding and analyte sensing in THz platform

Abstract

In present times, Photonic Crystal Fiber (PCF) has emergedas a strong contender for THz waveguiding and analyte sensing. Major benefits of a porous-core PCF include minimum absorption loss due to unique light-guiding process through a guided air medium, lower confinement loss, near-zero flattened dispersion, extensive detecting potential,faster response with precise results, and geometry design flexibility.Most importantly, the optical behaviors of the PCF can be controlled by thegeometrical specifications for both waveguiding and sensing cases. In this research, different novel geometries of PCF areproposed and numerically analyzed. Necessary optical properties are evaluated in the Terahertz (THz) platform for waveguiding and analyte sensing. The purpose is not only to provide high-quality THz transmission but also to render the ability for sensing different unknown analytes, basically several harmful and well-known liquid chemicals, biological components, and air pollutants, with high sensitivity. The various geometrical parameters of the PCFs have been optimized and the optical properties of the tuned PCFsare numerically investigated for wave propagation and sensing cases. The full vector analysis-based Finite Element Method (FEM) with COMSOL Multiphysics software (v. 5.3a) is employed to design, and evaluate the optical properties. As compared to existing works, a superior performance in terms of low losses, flattened waveguide dispersion, high core power fraction, and large effective area are obtained for THz wave guidance. For the liquid chemicals, biological components, and air pollutant analytes, a number of improvements are demonstrated that include higher sensitivity, negligible confinement loss, ultra-low effective material loss (EML), and moderate effective area, as compared to several recently reported results. Furthermore, in the context of current developments in fabrications, recommendations are provided regarding the potential for fabricating the proposed PCFs. Overall, the designed PCFs have a good degree of potential for diverse applications in the THz domain including wave transmission and sensing of different substances.