Spatial dynamics of laser-induced fluorescence in an intense laser beam: experiment and theory in alkali metal atoms

• Published in: arXiv.org
• Main Authors: Auzinsh, Marcis, Berzins, Andris, Ferber, Ruvin, Gahbauer, Florian, Kalnins, Uldis
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 26.10.2015
• Subjects: Alkali metals; Cesium; Dependence; Laser beams; Laser induced fluorescence; Lasers; Optical resonance; Physics - Atomic Physics; Rabi frequency
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1510.07518

We have shown that it is possible to model accurately optical phenomena in intense laser fields by taking into account the intensity distribution over the laser beam. We developed a theoretical model that divided an intense laser beam into concentric regions, each with a Rabi frequency that corresponds to the intensity in that region, and solved a set of coupled optical Bloch equations for the density matrix in each region. Experimentally obtained magneto-optical resonance curves for the \(F_g=2\longrightarrow F_e=1\) transition of the \(D_1\) line of \(^{87}\)Rb agreed very well with the theoretical model up to a laser intensity of around 200 mW/cm\(^2\) for a transition whose saturation intensity is around 4.5 mW/cm\(^2\). We have studied the spatial dependence of the fluorescence intensity in an intense laser beam experimentally and theoretically. An experiment was conducted whereby a broad, intense pump laser excited the \(F_g=4\longrightarrow F_e=3\) transition of the \(D_2\) line of cesium while a weak, narrow probe beam scanned the atoms within the pump beam and excited the \(D_1\) line of cesium, whose fluorescence was recorded as a function of probe beam position. Experimentally obtained spatial profiles of the fluorescence intensity agreed qualitatively with the predictions of the model.