Coherent population trapping in quantum systems

Four-wave mixing at maximum coherence and eliminated Doppler broadening controlled with the driving fields

“…Coherent coupling of laser radiation with multilevel quantum schemes has been used to manipulate energy level populations, nonlinear-optical response, refraction and absorption of a resonance medium [2]. Much attention has been shown to four-wave mixing (FWM) processes with maximal coherence on a Raman transition [3] based on the effect of coherence population trapping (CPT) [4], which allows a dramatic increase of conversion efficiency. In far-from-degenerate schemes, substantial Doppler broadening of the resonant quantum transitions gives rise to inhomogeneous coupling of the driving fields with the atoms in different velocity intervals.…”

Energy exchange between laser pulses in an atomic medium with a closed excitation contour

“…When the CPT-resonance is excited by two-frequency electromagnetic field, the propagation of continuous radiation obeys a linear law [1]. At the same time the CPTresonance becomes sensitive to the relative phase ) M M M of the fields when the third field takes place due to appearance of the closed excitation contour.…”

Energy Exchange Between Laser Pulses in Atomic Medium with a Closed Excitation Contour

“…In the last two decades a lot of works has been devoted to the coherent population trapping effect (CPT) [1]. The essence of this effect is the appearance of a specific superposition of long-lived states in a three-level atom ( / -system) which is excited by two-frequency radiation.…”