Room temperature terahertz quantum cascade laser source based on intracavity difference-frequency generation

We report on our progress in the development of a terahertz quantum cascade laser source based on intracavity terahertz difference-frequency mixing in a dual-wavelength mid-infrared quantum cascade laser with the active region engineered to possess giant second-order nonlinear susceptibility. In this letter, we demonstrate devices that operate in mid-infrared at ${\lambda }_1=8.9\mu \mathrm{m}$ and ${\lambda }_2=10.5\mu \mathrm{m}$ and produce terahertz output at $\lambda \approx 60\mu \mathrm{m}$ via difference-frequency generation with $7\mu \mathrm{W}$ output power at $80\mathrm{K}$ , $1\mu \mathrm{W}$ output at $250\mathrm{K}$ , and still approximately $300\mathrm{nW}$ output at $300\mathrm{K}$ .