De Broglie wavelength of a non-local four-photon state

13. May 2004  — (Nature 429, 158-161, 2004)


De Broglie wavelength of a non-local four-photon state

Graphic Design: Beth Anderson, ARKITEK Studios


We demonstrate the generation of four-photon entangled states and their subsequent utilization in pure four-particle interferometry. The observed interference fringes confirm the theoretical expectation that the de-Broglie wavelength of a four-photon state is one fourth of a single photon. This overcomes state-of-the-art two-particle interferometry and opens new possibilities in quantum metrology and in quantum imaging applications.