Generation of single-cycle THz transients with high electric-field amplitudes

Single-cycle terahertz (THz) transients in the frequency range 0.3-7 THz with electric-field amplitudes of more than 400 kV/cm are generated by four-wave mixing of the fundamental and the second harmonic of 25 fs pulses from a Ti:sapphire amplifier in ionized air. These transients are fully characterized by electrooptic sampling with ZnTe and GaP crystals. One can tune the center frequency of the THz transients by varying the length of the incident pulse. The electric-field amplitude increases linearly with the incident pulse energy. (c) 2005 Optical Society of America