POSTSELECTION-FREE ENERGY-TIME ENTANGLEMENT

摘要: We report a two-photon interference experiment that realizes postselection-free test of Bell's inequality based on energy-time entanglement. In contrast with all previous experiments this type, the employed entangled states are obtained without use beam splitter or short coincidence window to "throw away" unwanted amplitudes. A (95.0\ifmmode\pm\else\textpm\fi{}1.4)% fringe visibility is observed, implying strong violation Bell inequality. The scheme very compact and has demonstrated excellent stability, suggesting it may be useful, for example, in practical quantum cryptography.