To evaluate the uncertainty of concentration measurement using cavity ringdown spectroscopy, we analytically derived expressions for uncertainty for parameters, such as temperature, laser frequency, and ringdown time deviation, from the model equation. The uncertainties that are due to systematic errors in a practical cavity ringdown system were assessed through an experimental study of the PQ(35) transition in an A band of molecular oxygen. We found that, except for the line strength that is regarded as a reference value independent of the measurement, the laser frequency jitter is the largest uncertainty source in the system. Some practical requirements for minimizing the uncertainty in concentration measurements are discussed. We also demonstrated determination of the line strength of the PQ(35) transition line of oxygen to be 8.63(3) × 10-27 cm-1 with a relative uncertainty of less than 0.4%.
© 2001 Optical Society of America
Original Manuscript: July 27, 2000
Revised Manuscript: April 23, 2001
Published: October 20, 2001
Jae Wan Kim, Yong Shim Yoo, Jae Yong Lee, Jae Bong Lee, and Jae Won Hahn, "Uncertainty analysis of absolute concentration measurement with continuous-wave cavity ringdown spectroscopy," Appl. Opt. 40, 5509-5516 (2001)