Tunable, High-Power Terahertz Quantum Cascade Laser Local Oscillator

NASA and NASA funded missions/instruments such as Aura/MLS (Microwave Limb Sounder), SOFIA/GREAT and STO/STO-2 have demonstrated the need for local oscillator (LO) sources between 30 and 300 um (1 and 10 THz). For observations >2 THz, technologically mature microwave sources typically have microwatt power levels which are insufficient to act as LOs for a heterodyne receivers. LongWave Photonics is proposing to develop a high power, frequency tunable, phase/frequency-locked, single mode, External Cavity THz quantum cascade laser (ECT-QCL) system with >2 mW average power output and a clear path to increase the power to >10 mW. The system includes a THz QC gain chip based on SISP or metal-meal waveguide with integrated horn or lens structure to reduce facet reflectivity. Frequency selective external feedback will be frequency tunable over 100's of GHz, with center frequencies ranging from 2 to 5 THz. The gain chip will be packaged in a high-reliability Stirling cycle cooler. The source will be phase/frequency locked to a stable microwave reference synthesizer with <100 kHz line width.