Advances in Mathematical Physics
Volume 2010 (2010), Article ID 391607, 13 pages
doi:10.1155/2010/391607
Review Article

Quantum-Dot-Based Photon Emission and Media Conversion for Quantum Information Applications

H. Kumano,1,2 H. Nakajima,1 S. Ekuni,1 Y. Idutsu,1 H. Sasakura,1,2 and I. Suemune1,2

1Research Institute for Electronic Science, Hokkaido University, Kita-21 Nishi-10, Kita-ku, Sapporo 001-0021, Japan
2CREST, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan

Received 18 September 2009; Revised 9 December 2009; Accepted 18 January 2010

Academic Editor: Shao-Ming Fei

Copyright © 2010 H. Kumano et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Single-photon as well as polarization-correlated photon pair emission from a single semiconductor quantum dots is demonstrated. Single photon generation and single photon-pair generation with little uncorrelated multiphoton emission and the feasibility of media conversion of the quantum states between photon polarization and electron spin are fundamental functions for quantum information applications. Mutual media conversion for the angular momentum between photon polarization and electron spin is also achieved with high fidelity via positively charged exciton state without external magnetic field. This is a clear indication that the coupling of photon polarizations and electron spins keeps secured during whole processes before photon emission. Possibility of a metal-embedded structure is demonstrated with the observation of drastic enhancement of excitation and/or collection efficiency of luminescence as well as clear antibunching of photons generated from a quantum dot.