Figure 2

Relative permittivity of InSb (\({\varepsilon }_{\text{InSb}}\)) as a function of THz frequency under the variation of temperature (a) real part and (b) imaginary part with \({\varepsilon }_{\infty }=15.68\), \(\gamma =\pi \times {10}^{11}\text{ rad} {\text{s}}^{-1}\) and \({E}_{g}=0.26\text{ eV}\).