Frequency combs and hyperspectral sources for absorption spectroscopy

We have developed numerous laser sources for gathering spectral information from gases. Examples include frequency-comb sources that give complete broadband spectra, and time-division-multiplexed sources that cycle through key wavelengths aligned to gas absorption features (e.g. a source that cycles through 14 wavelengths in the 1325-1666 nm range every 33 mus). We have applied such sources for high-speed measurements of gas properties in combustion flows, for example gas thermometry in the 400-2200 K range at 100 kHz with a precision of 0.2%. Recent and ongoing activities will be summarized, including approaches for gas property imaging by tomographic reconstruction of hyperspectral absorption data.