12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Control of Exciton fine structure splitting in ...
View graph of relations

« Back

Control of Exciton fine structure splitting in quantum dots

Research output: Contribution to journalJournal article

Published

  • R. M. Stevenson
  • R. J. Young
  • P. Atkinson
  • K. Cooper
  • D. A. Ritchie
  • A. J. Shields

Associated organisational unit

Journal publication date09/2006
JournalActa Physica Polonica A
Journal number3
Volume110
Number of pages8
Pages311-318
Original languageEnglish

Abstract

Quantum dots have been identified as potential sources of entangled photon pairs, essential for many applications in quantum information. However, in practice structural properties of the dots result in polarisation splitting of the emission lines, which has prevented the realisation of such a source. Here, we present two techniques developed to control the polarisation splitting in a quantum dot both irreversibly and reversibly. We find that the splitting is strongly dependent upon the emission energy, or lateral confinement, of the quantum dot. Thus by precise control of the InAs deposition thickness, it is possible to produce ensembles from which dots with zero polarisation splitting can be easily selected. Additionally, we demonstrate that by using modest in-plane magnetic fields to partially mix the bright and dark exciton states, the polarisation splitting can be reversibly tuned to zero for most dots of a certain type. Finally, we demonstrate the emission of triggered entangled photon pairs from a quantum dot with approximately zero splitting with fidelity > 70%.