Characterization and optimization of photonic crystal fiber evanescent wave sensor for gas explosives detection in terahertz wave

Some gas explosives spectrum resonance absorption peaks is in terahertz wave, the relative sensitivity of evanescent wave solid core PCF sensor used for their sensing detection is simulated and calculated by finite element method (FEM). The relative sensitivity of PCF increases rapidly with the growth of operating wavelength, for the same operating wavelength, the larger the cladding d/lambda is, the higher the relative sensitivity is. Moreover, the relative sensitivity of several different fiber core structure PCF is also compared when d/lambda is set be 0.8, the relative sensitivity will increase with both the fiber core holes number and holes radius increase in the premise of not changing guide light principle. By simulating, the symmetric fiber core nine holes arranged square lattice PCF what holes radius is 50 mu m is the best choice for sensing detection application.