Coherent-population-trapping transients induced by a modulated transverse magnetic field

We present theoretical results of coherent-population-trapping transients induced by a modulated transverse magnetic field (TMF). The application of a transverse magnetic field causes the appearance of new Lambda subsystems, creation of new dark states, and rearrangement of the population among the Zeeman sublevels. We show that transients appear as the system is switched between steady-state situations, and we identify the various level system components of the total probe absorption. We discuss the time-dependent evolution of the probe absorption caused by the modulated TMF in the presence and absence of a constant longitudinal magnetic field (LMF). The differences between TMF modulation and LMF modulation are discussed.