Terahertz quantum-cascade-laser source based on intracavity difference-frequency generation Academic Article uri icon


  • The terahertz spectral range (λ = 30-300 νm) has long been devoid of compact, electrically pumped, room-temperature semiconductor sources. Despite recent progress with terahertz quantum cascade lasers, existing devices still require cryogenic cooling. An alternative way to produce terahertz radiation is frequency down-conversion in a nonlinear optical crystal using infrared or visible pump lasers. This approach offers broad spectral tunability and does work at room temperature; however, it requires powerful laser pumps and a more complicated optical set-up, resulting in bulky and unwieldy sources. Here we demonstrate a monolithically integrated device designed to combine the advantages of electrically pumped semiconductor lasers and nonlinear optical sources. Our device is a dual-wavelength quantum cascade laser with the active region engineered to possess giant second-order nonlinear susceptibility associated with intersubband transitions in coupled quantum wells. The laser operates at λ1 = 7.6 νm and λ2 = 8.7 νm, and produces terahertz output at λ = 60 νm through intracavity difference-frequency generation. © 2007 Nature Publishing Group.

author list (cited authors)

  • Belkin, M. A., Capasso, F., Belyanin, A., Sivco, D. L., Cho, A. Y., Oakley, D. C., Vineis, C. J., & Turner, G. W

complete list of authors

  • Belkin, Mikhail A||Capasso, Federico||Belyanin, Alexey||Sivco, Deborah L||Cho, Alfred Y||Oakley, Douglas C||Vineis, Christopher J||Turner, George W

publication date

  • January 1, 2007 11:11 AM