Generation and characterization of intense ultrashort tunable far-infrared (30-250 /spl mu/m) laser pulses

Summary form only. Intense rapidly tunable picosecond laser pulses have been generated in the far-infrared from 30-250 /spl mu/m, a range that is not well covered by other sources. The transform-limited, diffraction-limited laser pulses have energies of up to 17 /spl mu/J, peak powers of more than 1 MW, a length of only 18 periods of the optical field, and focused intensities of 0.1 GW/cm/sup 2/. Measurements of both the optical field amplitude and phase have been performed at 150 /spl mu/m with a rapid-scanning cross-correlation technique probing the field-induced birefringence in a ZnTe crystal with a 10-femtosecond Ti:sapphire laser. The far-infrared free-electron laser opens up the exciting possibility of performing non-linear experiments in a relatively unexplored spectral range.