Abstract: Subpicosecond terahertz (THz) pulses were generated by supershorted laser pulses pumping a nonlinearelectric-optical crystal LiNbO₃. Spectral analysis of THz pulse waveform reveals that the generation mechanism of THz radiation is nonlinear difference frequency effect. The laser power dependence of THz emission intensity was also investigated, the experimental curve slightly deviated from quadratic curve along with the increase of laser pumping power. By cooling of the crystal, the THz emission efficiency was increased.

Key words: terahertz (THz), difference frequency, electric-optical crystal, nonlinear effect, phonon