TOPAS based porous core photonic crystal fiber for terahertz chemical sensor

This paper contributes a novel design of photonic crystal fiber (PCF) with a combination of porous core structure and TOPAS as background material is proposed for chemical sensor in terahertz regime. A finite element method (FEM) has been used for investigation of the optical properties such as relative sensitivity, power fraction (PF), effective area, numerical aperture (NA) and confinement loss of the proposed structure. The findings of the simulations show that the proposed structure provides high relative sensitivity with low confinement loss for sensing different chemical substances like ethanol, benzene, and water. The relative sensitivity of the proposed sensor is 70 %, 68.59 % and 67.62 % for benzene, ethanol, and water, respectively at a frequency of 1.14 THz. Confinement loss of the proposed sensor has the order of 10(-11) dB/m, which is very low and therefore convenient for practical applications as chemical sensor. In addition, V parameter, Marcuse spot size (MSS) and Beam divergence (BD) are also carefully examined from 0.2 THz to 1.3 THz. The proposed sensor is mainly used to detect toxic chemicals for commercial purposes.