Waveguide-integrated terahertz-frequency quantum-cascade lasers for trace-gas detection applications

We demonstrate photonic-lattice THz QCLs lasing at 2.2, 2.56, 3.5 and 4.7 THz, targeting water, methane, hydroxyl and atomic oxygen absorption lines, respectively. A robust micro-machined waveguide block improves beam quality and enables future integration of complete THz heterodyne systems including a local oscillator, mixer, and feed-horn.