We present experimental observations of a nonclassic and nonlocal interference effect with frequency-entangled photon pairs. We observed two-photon interference in a Hong–Ou–Mandel interferometer by monitoring the coincidence-counting rate as we varied the path-length difference or the relative time delay between two photons. The quantum-mechanical probabilities of joint detection by two detectors that respond to different frequency components exhibit differences that depend not only on the arrangement of the detector pairs but on the spectral filtering. The experimental results provide more understanding of two-photon entanglement and of the interference effects that arise from superposition of indistinguishable probability amplitudes.
© 2003 Optical Society of America
Heonoh Kim, Jeonghoon Ko, and Taesoo Kim, "Two-particle interference experiment with frequency-entangled photon pairs," J. Opt. Soc. Am. B 20, 760-763 (2003)