Physical Review A
Two-photon interference in a standard Mach-Zehnder interferometer
Yanhua H. Shih, Alexander V. Sergienko, Morton H. Rubin, Thomas E. Kiess, C. O. Alley
Abstract
A pair of light quanta with different colors (155.9-nm difference in center wavelength) generated from parametric down-conversion was injected collinearly into one input port of a Mach-Zehnder interferometer. Coincidence interference behavior was studied over a wide range of optical path differences of the interferometer. A measurement of 75% interference visibility with oscillation of the pump frequency for a large optical path difference of the interferometer (43 cm) is the signature of a quantum two-photon entangled state, which reflects both particle and wave nature of the light quanta in one experiment.