Tunable, High-Power Terahertz Quantum Cascade Laser Local Oscillator

NASA applications include the use of the QCL as an LO for >2 THz receivers for future missions. Here the narrow linewidth (<100 kHz) of the QCLs can be used to resolve Doppler-limited low-pressure gasses (~MHz linewidth). The external cavity QCL LO will be a frequency tunable, compact replacement for any gas-laser LO. The resulting source will be a compact, reliable, table-top sized THz high power with narrow linewidth . It will be an easy-to-use platform for NASA researchers to study the performance of other key components in the receiver such as Schottky or HEB mixers. THz QC gain chip can also be used as the power amplifier providing gain for solid-state frequency multiplier or as the low noise preamplifier in the heterodyne receiver to reduce overall noise temperature.

Initial applications for this technology are mainly research markets for low-pressure gas spectroscopy. The narrow line width and the ability to provide real-time frequency information and frequency tunability of THz radiation also has great appeal. Another potential application is to replace THz gas laser used for THz detector power calibration. Long-term applications include industrial uses for trace gas detection. For industrial applications, the use of high-reliability, compact Stirling cycle coolers would greatly increase the usability of these QCL devices, which have traditionally required liquid nitrogen cooling or larger cryocooling systems. More »