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 um, or the pump wavelength 2 - 4.4 um, we were able to generate narrow-bandwidth (~100 GHz) terahertz wave packets, tunable between 0.9 and 3 THz, with the optical-to-terahertz photon conversion efficiency of 3.3%.