In this study, a TOPAS-based optical sensor for detecting alcohols in drinks and liquids, made of circular air holes (CAH) in the cladding and a hexahedron core is suggested here. In addition, COMSOL Multiphysics program for development and analysis of the sensing qualities of a PCF-based sensor using finite element technical as a solution. In the THz frequency band, the described C-PCF structure has an exceptionally high relative sensitivity of 86.60%, 88.70%, and 84.71%, and low confinement losses (CL_s) are 5.75 × 10⁻⁰⁸, 6.11 × 10⁻⁰⁸ dB/m and 5.70 × 10⁻⁰⁸ dB/m for three alcohols such as Ethanol (n = 1.354), Butanol (n = 1.399), and Propanol (n = 1.387), respectively at monitoring region of 1 THz. Alcohol is widely used in both the food and beverage sectors and chemical operations. The detection methods of alcohol thus must be accurate, accurate, and reliable. This content modeling and analysis in the terahertz frequency range is a novel TOPAS-based photonic crystal fiber (C-PCF). Moreover, the total power fraction and effective area are also determined in the terahertz frequency range. Due to its excellent waveguiding characteristics, this suggested sensor has the potential to be employed in alcohols detection as well as polarization preserving terahertz wave applications.