THz quantum-cascade laser as a local oscillator for SOFIA

We report on the development of a compact local oscillator (LO) for operation on board of SOFIA, namely for GREAT, the German Receiver for Astronomy at Terahertz Frequencies. The LO is a combination of a quantum-cascade laser (QCL) with a compact, low-input-power Stirling cooler. The output power is sufficient for pumping a hot-electron bolometer mixer. Frequency stabilization is achieved by locking to a molecular absorption line. Detectors operating at room temperature can be used for the stabilization as well. High-resolution molecular spectroscopic experiments demonstrate the usability of the QCL as a LO for SOFIA.