Cavity ringdown and laser-induced incandescence measurements of soot

Randy L. Vander Wal, Thomas M. Ticich

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


Currently laser-induced incandescence (LII) is widely used for the measurement of soot volume fraction. A particularly important aspect of the technique that has received less attention, however, is calibration. The applicability of cavity ringdown (CRD) for measurement of soot volume fraction fv is assessed, and the calibration of LII by means of CRD is demonstrated. The accuracy of CRD for fv determination is validated by comparison with traditional light extinction and path-integrated LII. By use of CRD, the quantification of LII for parts in 109 (ppb) fv levels is demonstrated. Results are presented that demonstrate the accuracy of CRD for a single laser pulse to be better than ±5% for measurement of ppb soot volume-fraction levels over a 1-cm path length. By use of CRD, spatially resolved LII signals from soot within methane–air diffusion flames are calibrated for ppb fv levels, thereby avoiding the extrapolation required of less sensitive methods in current use.

Original languageEnglish (US)
Pages (from-to)1444-1451
Number of pages8
JournalApplied optics
Issue number9
StatePublished - Mar 20 1999

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering


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