Reducing decoherence of the confined exciton state in a quantum dot by pulse-sequence control

TL;DR

This paper demonstrates that applying a sequence of ultra-short pulses can significantly reduce phonon-induced dephasing in quantum dot exciton states, enhancing coherence more effectively than single Gaussian pulses.

Contribution

It introduces a pulse-sequence control method that improves coherence in quantum dots by reducing phonon-induced dephasing, outperforming traditional single-pulse approaches.

Findings

Multiple pulses improve coherence more than single pulses.

2-3 pulses significantly reduce dephasing.

Optimized pulse sequences outperform smooth Gaussian pulses.

Abstract

We study the phonon-induced dephasing of the exciton state in a quantum dot excited by a sequence of ultra-short pulses. We show that the multiple-pulse control leads to a considerable improvement of the coherence of the optically excited state. For a fixed control time window, the optimized pulsed control often leads to a higher degree of coherence than the control by a smooth single Gaussian pulse. The reduction of dephasing is considerable already for 2-3 pulses.