Dressed-state analysis of two-color excitation schemes

TL;DR

This paper analyzes the SUPER two-color excitation scheme for quantum emitters, revealing how it induces population inversion through dressed-state transitions, and provides analytic and extended results for two- and three-level systems.

Contribution

It offers a detailed dressed-state analysis of the SUPER scheme, deriving analytic expressions and extending understanding to three-level systems for experimental applications.

Findings

SUPER can invert populations via dressed-state transitions

Analytic expressions for pulse parameters in two-level systems

Insights into three-level system behavior with strong state mixing

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.