The propagation of femtosecond-duration optical pulses in electro-optic materials is observed to produce a Cherenkov cone of pulsed far-infrared radiation in the terahertz spectral range. Coherent detection of the electric field of this far-infrared pulse by electro-optic sampling shows it to have a duration of approximately one cycle and an amplitude of 10 V/cm making it a potentially attractive source for transient far-infrared spectroscopy.

• Received 17 July 1984

DOI:https://doi.org/10.1103/PhysRevLett.53.1555