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

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

作者机构：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 

出 版 物：《Physical Review A》 (物理学评论A辑：原子、分子和光学物理学)

年 卷 期：2015年第92卷第4期

页      面：043408-043408页

核心收录：

学科分类：070207[理学-光学] 07[理学] 08[工学] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：European Commission  (251391  REGPOT-CT-2011-285912-FOTONIKA) 

主　　题：ATOMIC beams PARTICLE beams EXCITATION spectrum POPULATION dynamics NUMERICAL integration 

摘      要：By photoionizing hyperfine (HF) levels of the Cs state 62P3/2 in a slow and cold atom beam, we find how their population depends on the excitation laser power. The long time (around 180μs) 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.