Terahertz-wave generation in quasi-phase-matched GaAs

The authors demonstrate an efficient room temperature source of terahertz radiation using femtosecond laser pulses as a pump and GaAs structures with periodically inverted crystalline orientation, such as diffusion-bonded stacked GaAs and epitaxially grown orientation-patterned GaAs, as a nonlinear optical medium. By changing the GaAs orientation-reversal period (504-1277 mu m), or the pump wavelength (2-4.4 mu m), we were able to generate narrow-bandwidth (similar to 100 GHz) terahertz wave packets, tunable between 0.9 and 3 THz, with the optical-to-terahertz photon conversion efficiency of 3.3%. (c) 2006 American Institute of Physics.