How weak is a weak probe in laser spectroscopy?

Sherlock, B.E.; Hughes, I.G.

Abstract

Laser spectroscopy experiments are often conducted with a probe that does not significantly alter the medium’s properties. For a two-level atom a clear measure of the strength of a probe beam in terms of the saturation intensity is known. We show that for a multilevel atom the situation is very different, and the effects of optical pumping are crucial to understanding the opacity of the medium. We present a simple theoretical analysis for Doppler-broadened spectroscopy of alkali metals on the D2 line that emphasizes the importance of the transient nature of the population dynamics, and the crucial role of the distribution of the times of flight of atoms through the probe beam. Experimental results are obtained with room temperature rubidium vapor probed by an extended-cavity diode laser and confirm our theoretical prediction.

Citation

Sherlock, B., & Hughes, I. (2009). How weak is a weak probe in laser spectroscopy?. American Journal of Physics, 77(2), 111-115. https://doi.org/10.1119/1.3013197

• Journal Article Type: Article
• Publication Date: Feb 1, 2009
• Deposit Date: Jan 26, 2012
• Journal: American Journal of Physics
• Print ISSN: 0002-9505
• Publisher: American Association of Physics Teachers
• Peer Reviewed: Peer Reviewed
• Volume: 77
• Issue: 2
• Pages: 111-115
• DOI: https://doi.org/10.1119/1.3013197
• Keywords: Atom-photon collisions, Doppler measurement, Optical pumping, Optical saturation, Quantum optics, Rubidium, Spectroscopic light sources.
• Public URL: https://durham-repository.worktribe.com/output/1519766