Temperature evolution of the dielectric response of $\alpha$-lactose monohydrate in the THz frequency range

Transmission spectra of pressed microcrystalline $\alpha$-lactose monohydrate samples have been measured by THz time-domain spectroscopy in the temperature range of existence of the solid phase (10–475 K). An analysis of the observed absorption lines using the model of classical oscillator have revealed complex temperature evolution of resonance eigenfrequencies and determined the range of existence of a phase of $\alpha$-lactose monohydrate response. The obtained data can be used in practice in various fields of THz optics, including pharmacology, food industry, analytical chemistry, and biophotonics.