Decoherence processes during active manipulation of excitonic qubits in semiconductor quantum dots

TL;DR

This study investigates how decoherence affects excitonic qubits in quantum dots during active manipulation, revealing that damping is mainly due to non-resonant carrier excitation in the wetting layer, especially with shorter pulses.

Contribution

It provides a detailed analysis of Rabi oscillation damping mechanisms in excitonic qubits, highlighting the impact of pulse duration and non-resonant excitation effects.

Findings

Damping increases with shorter pulse widths.

Rabi oscillations are observable for up to 5 periods.

Non-resonant carrier excitation causes damping.

Abstract

Using photoluminescence spectroscopy, we have investigated the nature of Rabi oscillation damping during active manipulation of excitonic qubits in self-assembled quantum dots. Rabi oscillations were recorded by varying the pulse amplitude for fixed pulse durations between 4 ps and 10 ps. Up to 5 periods are visible, making it possible to quantify the excitation dependent damping. We find that this damping is more pronounced for shorter pulse widths and show that its origin is the non-resonant excitation of carriers in the wetting layer, most likely involving bound-to-continuum and continuum-to-bound transitions.