Creating polarization-entangled photon pairs from a semiconductor quantum dot using the optical Stark effect.
In typical epitaxial quantum dots (QDs) the ideally degenerate optical excitons are energy split, preventing the formation of two-photon entanglement in a biexciton decay. We use an external field, here a continuous-wave laser tuned to the QD in the ac Stark limit, to cancel the splitting and create two-photon entanglement. Quantum-state tomography is used to construct the two-photon density matrix. When the splitting is removed it satisfies well-known entanglement tests. Our approach shows that polarization-entangled photons can be routinely produced in semiconductor nanostructures.
Muller
Andreas
A
Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland, USA. andreas.muller@nist.gov
Fang
Wei
W
Lawall
John
J
Solomon
Glenn S
GS