Characterization of domain structure of periodically poled Mg:LiNbO3 through multifrequency terahertz generation

Terahertz (THz) wave generation in a periodically poled Mg:LiNbO3 crystal was detected by a pump-probe technique and analyzed using frequency and time-frequency spectra. Multifrequency THz waves were clearly observed, providing information about the domain structure of the crystal. A theoretical T-function model was used to fit the frequency spectrum. A method that can characterize the detailed domain structure and THz capabilities of the inner crystal's parts is proposed.