Coherence and degree of time-bin entanglement from quantum dots

TL;DR

This paper demonstrates the generation of highly entangled time-bin photon pairs from quantum dots, optimizing excitation parameters to maximize entanglement quality and analyzing dephasing effects.

Contribution

It introduces a method to optimize pulsed resonant excitation in quantum dots for enhanced time-bin entanglement, supported by theoretical modeling.

Findings

Achieved a concurrence of up to 0.78 indicating high entanglement

Optimized pulse duration reduces laser-induced dephasing

Identified power-dependent dephasing limits coherence

Abstract

We report on the generation of time-bin entangled photon pairs from a semiconductor quantum dot via pulsed resonant biexciton generation. Based on theoretical modeling we optimized the duration of the excitation pulse to minimize the laser-induced dephasing and increase the biexciton-to-background single exciton occupation probability. This results in a high degree of entanglement with a concurrence of up to 0.78(6) and a 0.88(3) overlap with a maximally entangled state. Theoretical simulations also indicate a power dependent nature of the dephasing during the laser excitation that limits the coherence of the excitation process.