  We demonstrate a novel way to efficiently and very robust create an
entanglement between an atomic and a photonic qubit. A single laser beam is
used to excite one atomic ensemble and two different spatial modes of scattered
Raman fields are collected to generate the atom-photon entanglement. With the
help of build-in quantum memory, the entanglement still exists after 20.5
$\mu$s storage time which is further proved by the violation of CHSH type
Bell's inequality. Our entanglement procedure is the building block for a novel
robust quantum repeater architecture [Zhao et al, Phys. Rev. Lett. 98, 240502
(2007)]. Our approach can be easily extended to generate high dimensional
atom-photon entanglements.
