THz spectrum of KDP crystal

THz time domain spectrum of KH
₂
PO
₄
crystal has been measured in the range from 0.2 THz to 1.6 THz. Ultraviolet-visible-infrared spectra have been measured in the range from 190 nm to 1600 nm at the room temperature. The energy band gap Eg of KH
₂
PO
₄
crystal is 5.90 eV. There is a wide band of the phonon absorption in the KDP crystal. The frequency omega
_LO
of the longitudinal optical phonon model LO is about 1.29times10
¹⁵
Hz. Frequency omega
_TO
of the transverse optical phonon model TO is about 6.28times10
¹²
Hz.