  We experimentally demonstrate optimal entanglement distillation from two
forms of two-qubit mixed states under local filtering operations according to
the constructive method intruduced by F. Verstraete et al. [Phys. Rev. A 64,
010101(R) (2001)]. In principle, our set-up can be easily applied to distilling
entanglement from arbitrary two-qubit partially mixed states. We also test the
violation of the Clauser-Horne-Shinmony-Holt (CHSH) inequality for the
distilled state from the first form of mixed state to show its "hidden
non-locality".
