Coherent Mechanism of Robust Population Inversion

Abstract

A coherent mechanism of robust population inversion in atomic and molecular systems by a chirped field is presented. It is demonstrated that a field of sufficiently high chirp rate imposes a certain relative phase between a ground and excited state wavefunction of a two-level system. The value of the relative phase angle is thus restricted to be negative and close to 0 or $-\pi$ for positive and negative chirp, respectively. This explains the unidirectionality of the population transfer from the ground to the excited state. In a molecular system composed of a ground and excited potential energy surface the symmetry between the action of a pulse with a large positive and negative chirp is broken. The same framwork of the coherent mechanism can explain the symmetry breaking and the population inversion due to a positive chirped field.

11 pages, 3 figures

Cited by in corpus (3)

• Making ultracold molecules in a two color pump-dump photoassociation scheme using chirped pulses
• Towards controlling the dissociation probability by light-induced conical intersections
• Adiabatic dynamics in a V-type quantum system by oppositely chirped counterrotating circularly polarized laser pulses