Influence of laser intensity on absorption line broadening in laser absorption spectroscopy

The influence of laser intensity on absorption line broadening was investigated. Laser absorption spectroscopy was applied to low-pressure plasma, and the translational temperature deduced from the Doppler width was found to increase with laser intensity; this was in contrast to the conventional laser theory. Consequently, the dependency of absorption saturation on the Doppler frequency was considered. The predicted variation in broadening width with laser intensity showed a good agreement with the measurement. In addition, we obtained a correction factor for the temperature measurement at high laser intensity. (c) 2006 American Institute of Physics.