Related Experiment Video
Updated: Jun 8, 2026

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
Published on: October 13, 2017
Observation of spin-dependent quantum jumps via quantum dot resonance fluorescence
A N Vamivakas1, C-Y Lu, C Matthiesen
1Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK. anv21@cam.ac.uk
Abstract:
Reliable preparation, manipulation and measurement protocols are necessary to exploit a physical system as a quantum bit. Spins in optically active quantum dots offer one potential realization and recent demonstrations have shown high-fidelity preparation and ultrafast coherent manipulation. The final challenge-that is, single-shot measurement of the electron spin-has proved to be the most difficult of the three and so far only time-averaged optical measurements have been reported. The main obstacle to optical spin readout in single quantum dots is that the same laser that probes the spin state also flips the spin being measured. Here, by using a gate-controlled quantum dot molecule, we present the ability to measure the spin state of a single electron in real time via the intermittency of quantum dot resonance fluorescence. The quantum dot molecule, unlike its single quantum dot counterpart, allows separate and independent optical transitions for state preparation, manipulation and measurement, avoiding the dilemma of relying on the same transition to address the spin state of an electron.
Related Concept Videos
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...
NMR Spectroscopy: Spin–Spin Coupling
Atomic Spectroscopy: Absorption, Emission, and Fluorescence
UV–Vis Spectroscopy: Molecular Electronic Transitions
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
Atomic Fluorescence Spectroscopy

