Observation of Faraday rotation from a single confined spin

Atatüre, M., Dreiser, J., Badolato, A. and Imamoglu, A. (2007) Observation of Faraday rotation from a single confined spin. Nature Physics, 3(2), pp. 101-105. (doi: 10.1038/nphys521)

Abstract

The ability to read out the state of a single confined spin lies at the heart of solid-state quantum-information processing1. Although spin measurements using Faraday rotation of light polarization have been implemented in semiconductor spin ensembles2,3,4, single-spin read-out has only been achieved using transport measurements5,6. Here, we demonstrate an all-optical dispersive measurement of the time-averaged spin state of a single electron in a quantum dot. We obtain information on the spin state through conditional Faraday rotation of a spectrally detuned laser, induced by the polarization- and spin-selective trion (charged quantum dot) transitions. To assess the sensitivity of the technique, we use an independent resonant laser for spin-state preparation7. We infer that there are ∼10 spin-flip Raman scattering events (that is, back-action) within our measurement timescale. Straightforward improvements such as incorporating solid-immersion lenses8,9 and higher efficiency detectors should allow for back-action-evading spin measurements, without the need for a cavity.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: UNSPECIFIED
• Authors: Atatüre, M., Dreiser, J., Badolato, A., and Imamoglu, A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Nature Physics
• Publisher: Nature Research
• ISSN: 1745-2473
• ISSN (Online): 1745-2481