Entanglement generation by Fock-state filtration.
We demonstrate a Fock-state filter which is capable of preferentially blocking single photons over photon pairs. The large conditional nonlinearities are based on higher-order quantum interference, using linear optics, an ancilla photon, and measurement. We demonstrate that the filter acts coherently by using it to convert unentangled photon pairs to a path-entangled state. We quantify the degree of entanglement by transforming the path information to polarization information; applying quantum state tomography we measure a tangle of T=(20+/-9)%.
Department of Physics & Centre for Quantum Computer Technology, University of Queensland, Brisbane, QLD 4072, Australia.
K J
KJ
Resch
J L
JL
O'Brien
T J
TJ
Weinhold
K
K
Sanaka
B P
BP
Lanyon
N K
NK
Langford
A G
AG
White