Possibility of intracavity terahertz difference frequency generation in a two-frequency GaAsP/AlGaAs/GaAs quantum well laser.

We consider the GaAsP/AlGaAs/GaAs laser design with two different quantum wells for simultaneous generation of ${{\rm{TE}}_0}$ and ${{\rm{TM}}_0}$ modes having different frequencies in near-IR range. We theoretically investigate the possibility of effective difference frequency generation in the 7.5-8 and 10.5-11 THz regions in the laser design proposed. Resonant increase of second-order susceptibility in AlGaAs in these ranges provides sufficient generation efficiency. We demonstrate an output power-conversion factor for the difference frequencies in the 7.5-8 THz range to be up to ${{4 {-} 8}}\;{{\rm{MW}}^{- 1}}$ at room temperature in such a laser.