Narrow-line phase-locked quantum cascade laser in the 9.2~micron range.

4 pagesWe report on the operation of a 50~mW continuous wave quantum cascade laser (QCL) in the 9.2 micrometer range, phase locked to a single mode CO2 laser with a tunable frequency offset. The wide free running emission spectrum of the QCL (3-5~MHz) is strongly narrowed down to the kHz range making it suitable for high resolution molecular spectroscopy