New high-efficiency source of a three-photon W state and its full characterization using quantum state tomography -: art. no. 150404

We propose and demonstrate a new scheme of high-efficiency generation of the three-photon polarization-entangled W state, which is a typical three-qubit entangled state. The high efficiency has enabled the first full characterization of the state by quantum state tomography. We have analyzed the obtained state and observed its nature of tripartite entanglement and robustness of entanglement.