Design and analysis of a chemical sensing octagonal photonic crystal fiber (O-PCF) based optical sensor with high relative sensitivity for terahertz (THz) regime

This article represents a new structure of octagonal cladding with a rotated-hexa core in photonic crystal fiber (O-PCF) for chemical sensing application in the terahertz (THz) waveguide. The five layers octagonal shape in circular air holes of cladding region with two layers rotated-hexa shape in circular air holes of core area are proposed in this study. The mathematical analysis is achieved from the technique of perfectly matched layers (PML) boundary condition with a finite element method (FEM) at the terahertz (THz) wave propagation. After the simulation process, the designed O-PCF sensor performs the extreme relative sensitivity at 77.14%, 78.06% and 76.11% at 1 THz for three chemicals such as Ethanol (n = 1.354), Benzene (n = 1.366) and Water (n = 1.330). Alternatively, the low confinement losses are 2.26 x 10(-03) dB/m, 3.02 x 10(-06) dB/m and 2.72 x 10(-02) dB/m for similar three chemicals at 1 THz. The effective area, effective mode index and total power fraction are also concisely explained here. Furthermore, we hope that the suggested excellent designed of octagonal photonic crystal fiber (O-PCF) can be utilized particularly for chemical sensing in material study, industrial areas, nano-optics, biomedical and others communication areas in THz technology.