Terahertz-wave generation in quasi-phase-matched GaAs

Abstract

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 μ m ) , or the pump wavelength ( 2 – 4.4 μ m ) , 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%.