Frequency tunable THz source based on optical down conversion in orientation patterned GaAs

The generation of narrow-band THz radiation is demonstrated in orientation patterned GaAs structures via frequency down-conversion of short optical pulses. Frequency of THz radiation is tunable in the range 0.8-3 THz. Optical to THz power conversion efficiency reaches 0.1%, corresponding to internal photon conversion efficiency of 10%.