Relative permittivity of bulk Parylene-C polymer in the infrared regime

Infrared spectroscopy experiments in the 15–149 THz spectral regime were performed in the transmission mode on a thin film of bulk Parylene-C polymer at normal incidence. The relative permittivity of bulk Parylene-C polymer in this regime was modeled as comprising a frequency-independent term as well as contributions from 32 Lorentz oscillators. A least-squares minimization algorithm and a hybrid genetic algorithm were used to determine the frequency-independent term as well as all parameters characterizing the Lorentz oscillators from the measured transmittance spectrum itself.