Highly sensitive photonic crystal fiber liquid sensor in terahertz frequency range

Abstract We propose a highly sensitive hollow core photonic crystal fiber (HCPCF) for liquid sensing in the terahertz (THz) region. Asymmetrical rectangular shaped air holes in the cladding region along with Topas glass as a background material is used to get high sensitivity and low confinement loss. The full vector finite element method (FEM) is used to calculate relative sensitivity and other parameters of the proposed liquid sensor where frequency range is taken from 1 THz to 2 THz. The strut distance variations are also studied in this study to find out minimum strut length to make the proposed sensor fabrication friendly. Numerical analysis shows the maximum relative sensitivity of 91.42% for water, 92.55% for acetic acid and 94.03% for chloroform at optimal conditions along with the minimum confinement loss of 1.06 × 10−9cm−1 for water, 2.02 × 10−10cm−1 for acetic acid and 1.39 × 10−11cm−1 for chloroform. To the best of our knowledge, the proposed HCPCF sensor shows maximum relative sensitivity for liquid.