High-precision pressure shifting measurement technique using frequency-stabilized cavity ring-down spectroscopy

✍ Scribed by David J. Robichaud; Joseph T. Hodges; Daniel Lisak; Charles E. Miller; Mitchio Okumura

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 221 KB
• Volume: 109
• Category: Article
• ISSN: 0022-4073
• DOI: 10.1016/j.jqsrt.2007.06.005

✦ Synopsis

We describe a high-precision method for measuring pressure shifting of absorption lines. The technique involves the acquisition of high-resolution spectra using a cavity ring-down spectrometer whose length is continuously locked to a frequency-stabilized reference laser over a range of sample pressures. We discuss a relatively large correction arising from the pressure-dependence of dispersion in the cavity modes, and we demonstrate pressure shifting measurements in air for transitions in the 16 O 2 A-band. Pressure shifts in the range À0:011 to À0:007 cm À1 atm À1 are reported. We measured relative positions of line centers to within 70 kHz and determined pressure shifting coefficients over a 5 kPa pressure range with relative uncertainties approximately equal to 1.0%, which constitutes a five-fold improvement over previous measurements.