Compact source of continuously and widely-tunable terahertz radiation.

We report a THz radiation source based on the technique of noncollinear phasematched parametric generation. The source, which is compact and operable at room temperature, generates nanosecond pulses of peak power and energy greater than 1W and 5 nJ respectively. The radiation is continuously tunable over the range 1.2-3.05 THz and is of narrow spectral bandwidth (< 100 GHz). The use of intersecting pump and parametric wave cavities results in threshold pump pulse energies below 1 mJ (from a Nd:YAG laser excited at 20 W, 500 mu sec by a quasi-CW diode-laser) and close to 50% down-conversion efficiency when operated at twice threshold. (c) 2006 Optical Society of America.