Terahertz detection of chemical analytes using a hollow-core photonic crystal fiber sensor

Abstract

One novel Topas-based Photonic Crystal Fiber (PCF) has been modeled and analyzed for chemical analytes detection in terahertz frequency range. The sensor was realized by filling different kinds of chemical analytes in the hollow core of the PCF, consisting of five layers air holes of hexagonal lattices in the cladding. The propagation characteristics of proposed sensor have been investigated by adopting the Full Vectorial-Finite Element Method (FV-FEM) with anisotropic perfectly matched layers (PMLs). Numerical results indicated that the hollow-core provided a high relative sensitivity as well as low transmission loss. When optimal design parameter was selected as core diameter 𝐷_core = 400 μm, the PCF sensor showed high relative sensitivity of 80.32%, 83.3%, 84.64% with negligible confinement loss of 1.01×10⁻¹⁰ cm⁻¹, 7.65×10⁻¹¹ cm⁻¹, 7.49×10⁻¹¹ cm⁻¹ at 1 THz frequency for Water, Ethanol, Benzene, respectively. Moreover, other important mode properties such as the core power fraction, Effective Material Loss and dispersion, were discussed completely in the terahertz frequency range. With the outstanding waveguiding properties, the simple sensor can be produced at a low cost and provided a new avenue for chemical sensing.