Coherent Anti-Stokes Raman Spectroscopy (CARS) is a reliable laser based temperature and species diagnostics used in combustion systems and other harsh environments where traditional measurements are not possible. The technique utilizes relatively intense laser beams focused to a point inside a probe volume where they interact with resonant molecules generating a coherent signal beam. The signal beam is directed to a spectrometer and the resulting spectral measurement can be analyzed to determine the temperature and species concentration of the probe volume. CARS systems are typically built on large optical tables in dedicated laboratory areas due to such factors as: (1) the high intensity of the laser beams needed to generate the nonlinear interaction in gas phase systems, (2) the requirements of beam formatting and dye pumping, and (3) the high spectral resolution required for the analysis of the CARS signals.
OptoKnowledge has developed multiple technologies, including small footprint compact-CARS system, hollow fibers for remote delivery, and custom fiber fed spectrometer for signal analysis.
Kriesel, J. M., Garman, J. D, Hagglund, G. M., Gat, N., Papac, M. J., Dunn-Rankin, D., and Danczyk, S. A., "Compact and Rugged Coherent Anti-Stokes Raman Spectroscopy (CARS) System for Measurements of Temperature in Rocket Test Stands and Other Harsh Operating Environments," Proceedings of JANNAF 42nd Combustion Subcommittee Meeting, Boston MA, May, 2008.