  We report the observation of entanglement between a single trapped atom and a
single photon at a wavelength suitable for low-loss communication over large
distances, thereby achieving a crucial step towards long range quantum
networks. To verify the entanglement we introduce a single atom state analysis.
This technique is used for full state tomography of the atom-photon qubit-pair.
The detection efficiency and the entanglement fidelity are high enough to allow
in a next step the generation of entangled atoms at large distances, ready for
a final loophole-free Bell experiment.
