Scientific Results

Nonlinear effects in optical pumping of a cold and slow atomic beam

Year: 2015

Authors: Porfido N., Bezuglov N.N., Bruvelis M., Shayeganrad G., Birindelli S., Tantussi F., Guerri I., Viteau M., Fioretti A., Ciampini D., Allegrini M., Comparat D., Arimondo E., Ekers A., Fuso F.

Autors Affiliation: Dipartimento di Fisica Enrico Fermi, Università di Pisa, 56127 Pisa, Italy; Faculty of Physics, St. Petersburg State University, 198904 St. Petersburg, Russia; Department of Physics, University ITMO, 197101 St. Petersburg, Russia;
Institute of Atomic Physics and Spectroscopy, University of Latvia, LV-1586 Riga, Latvia; Orsay Physics, TESCAN Orsay, 13710 Fuveau, France; Istituto Nazionale di Ottica, INO-CNR, 56124 Pisa, Italy; Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, CNISM, Sezione di Pisa, 56127 Pisa, Italy; Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, 91405 Orsay, France; Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia

Abstract: By photoionizing hyperfine (HF) levels of the Cs state 6 P-2(3/2) in a slow and cold atom beam, we find how their population depends on the excitation laser power. The long time (around 180 mu s) spent by the slow atoms inside the resonant laser beam is large enough to enable exploration of a unique atom-light interaction regime heavily affected by time-dependent optical pumping. We demonstrate that, under such conditions, the onset of nonlinear effects in the population dynamics and optical pumping occurs at excitation laser intensities much smaller than the conventional respective saturation values. The evolution of population within the HF structure is calculated by numerical integration of the multilevel optical Bloch equations. The agreement between numerical results and experiment outcomes is excellent. All main features in the experimental findings are explained by the occurrence of \”dark\” and \”bright\” resonances leading to power-dependent branching coefficients.

Journal/Review: PHYSICAL REVIEW A

Volume: 92 (4)      Pages from: 043408  to: 043408

More Information: N.P., G.S., A.F., I.G., D.C., M.V., and F.F. acknowledge gratefully the support of the European Commission Seventh Framework Programme under Grant No. 251391 MC-IAPP \”COLDBEAMS.\” This collaborative work was supported also by the European Commission Seventh Framework Programme IRSES project COLIMA and the Centre of Excellence FOTONIKA-LV (European Commission Seventh Framework Programme project REGPOT-CT-2011-285912-FOTONIKA). N.B. acknowledges the support from Government of the Russian Federation Grant No. 074-U01, and M.B. and A.E. acknowledge the support from U.S. Office of Naval Research Grant No. N00014-12-1-0514. We thank Professor M. Auzinsh for helpful discussions on the bright-resonance phenomena and N. Puccini and E. Andreoni for their assistance with the experiment.
DOI: 10.1103/PhysRevA.92.043408

Citations: 6
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