Fig. 7.

Outlook: A miniature broad-band light source (e.g., a fiber laser, mode-locked QCL, or mode-locked microresonator) is combined on-chip waveguides to produce light in targeted spectral bands for spectroscopy. A micro GC on a chip separates complex samples and sends molecules into a microcavity which allows for high sensitivity of the micro-comb (upper figure). Due to the small size and low power requirements, these instruments can be deployed on aircraft, satellites, or sensor networks in cities (lower left) or as instruments on rovers that visit other planets (lower right). Lower left and lower right figures courtesy of NASA/JPL-Caltech.