Biexciton state preparation in a quantum dot via adiabatic rapid passage: comparison between two control protocols and impact of phonon-induced dephasing

TL;DR

This paper theoretically analyzes how to efficiently prepare a biexciton state in a quantum dot using adiabatic rapid passage, considering phonon effects, and compares different optical control protocols for optimal fidelity.

Contribution

It provides a comparative analysis of two control protocols for biexciton preparation and examines the impact of phonon-induced dephasing, highlighting conditions for high-fidelity state preparation.

Findings

Positive chirps and low temperatures improve biexciton preparation fidelity.

Resonant two-photon or two-color schemes are advantageous depending on biexciton binding energy.

Biexciton yield increases significantly below 4 K.

Abstract

We investigate theoretically under which conditions a stable and high-fidelity preparation of the biexciton state in a quantum dot can be realized by means of adiabatic rapid passage in the presence of acoustic phonon coupling. Our analysis is based on a numerically complete real-time path integral approach and comprises different schemes of optical driving using frequency-swept (chirped) pulses. We show that depending on the size of the biexciton binding energy, resonant two-photon excitations or two-color schemes can be favorable. It is demonstrated that the carrier-phonon interaction strongly affects the efficiency of the protocols and that a robust preparation of the biexciton is restricted to positive chirps and low temperatures. A considerable increase of the biexciton yield can be achieved realizing temperatures below 4 K.