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Updated: Sep 4, 2025

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
Enhanced Spin Coherence of a Self-Assembled Quantum Dot Molecule at the Optimal Electrical Bias
Kha X Tran1, Allan S Bracker1, Michael K Yakes1
1Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, USA.
Abstract:
A pair of coupled dots with one electron in each dot can provide improvements in spin coherence, particularly at an electrical bias called the "sweet spot," but few measurements have been performed on self-assembled dots in this regime. Here, we directly measure the T_{2}^{*} coherence time of the singlet-triplet states in this system as a function of bias and magnetic field, obtaining a maximum T_{2}^{*} of 60 ns, more than an order of magnitude higher than an electron spin in a single quantum dot. Our results uncover two main dephasing mechanisms: electrical noise away from the sweet spot, and a magnetic field dependent interaction with nuclear spins due to a difference in g factors.
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