Speed-dependent Voigt dispersion line-shape function: applicable to techniques measuring dispersion signals
2012 (English)In: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, Vol. 29, no 10, 2971-2979 p.Article in journal (Refereed) Published
An analytical expression for a Voigt dispersion line-shape function that incorporates speed-dependent effects (SDEs) on the collision broadening, applicable to spectroscopic techniques that measure dispersion signals, is presented. It is based upon a speed-dependent Voigt (SDV) model for absorption spectrometry that assumes that the molecular relaxation rate has a quadratic dependence on molecular speed. The expression is validated theoretically in the limit of small SDEs by demonstration that it reverts to the ordinary Voigt dispersion line-shape function and experimentally in a separate work by experiments performed by the noise-immune cavity-enhanced optical heterodyne molecular spectrometry technique. A comparison is given between the SDEs in the SDV absorption and dispersion line-shape functions. It is shown that both line shapes are affected significantly but differently by SDEs. The expression derived provides, for the first time to our knowledge, a possibility also for the techniques that measure dispersion signals to handle SDEs. (c) 2012 Optical Society of America
Place, publisher, year, edition, pages
Washington: Optical Society of America, 2012. Vol. 29, no 10, 2971-2979 p.
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:umu:diva-61566DOI: 10.1364/JOSAB.29.002971ISI: 000309588200045OAI: oai:DiVA.org:umu-61566DiVA: diva2:572685