Dressed-state analysis of two-color excitation schemes

Abstract

To coherently control a few-level quantum emitter, typically pulses with an energy resonant to the transition energy are applied making use of the Rabi mechanism, while a single off-resonant pulse does not result in a population inversion. Surprisingly, a two-color excitation with a combination of two off-resonant pulses making use of the Swing-UP of quantum EmitteR population (SUPER) mechanism is able to invert the system. In this paper, we provide an in-depth analysis of the SUPER scheme within the dressed-state picture. We show that the SUPER mechanism can be understood as a driving of the transition between the dressed states. In the two-level system this allows us to derive analytic expressions for the pulse parameters yielding a population inversion. We extend our considerations to the three-level system, where a strong mixing between the bare states takes place. The insights gained from these results help in finding accessible regimes for further experimental realizations of the SUPER scheme and similar two-color excitation schemes.