Comparative study of the transient evolution of Hanle electromagnetically induced transparency and absorption resonances
Paulo Valente, H. Failache, A. Lezama
The temporal evolutions of electromagnetically induced transparency (EIT) and absorption (EIA) were observed in a Hanle absorption experiment carried on the ${D}_{2}$ lines of ${}^{87}\mathrm{Rb}$ vapor by suddenly turning the magnetic field on or off. The main features of the experimental observations are well reproduced by a theoretical model based on Bloch equation where the atomic level degeneracy has been fully accounted for. Similar (opposite phase) evolutions were observed at low optical-field intensities for Hanle-EIT or Hanle-EIA resonances. Unlike the Hanle-EIA transients that are increasingly shorter for driving field intensities approaching saturation, the $B\ensuremath{\ne}0$ transient of the Hanle-EIT signal at large driving field intensities present a long decay time approaching the atomic transit time. Such counterintuitive behavior is interpreted as a consequence of the Zeno effect.
Physical Review A•Jan 15, 2002•45 citations