G. Lima, L. Neves, I.F. Santos, C.H. Monken, J.G. Aguirre-Goméz, C. Saavedra and S. Pádua
INTERNATIONAL JOURNAL OF QUANTUM INFORMATION 5 (2007)
We report an experiment to generate and propagate two entangled spatial qudits, D-dimensional quantum systems, using spontaneous parametric down-conversion. The manipulation, via pump beam, of the transverse spatial correlation between the photon pairs is explored. Inserting apertures with D-slits in the arms of the down-converted photons, we associate the qudit space with the D possible paths followed by each photon. Experimental results for qudits with D = 4 and 8 are shown. We demonstrate that the generated states cannot be classically correlated. We also show the propagation of entangled states of spatial qudits. Their free-space distribution is performed at the laboratory scale and the propagated states maintain a high fidelity with their original form.