title: Quantum interference fringes beating the diffraction limit.
abstract: Spatially formed two-photon interference fringes with fringe periods smaller than the diffraction limit are demonstrated. In the experiment, a fringe formed by two-photon NOON states with wavelength lambda=702.2 nm is observed using a specially developed near-field scanning optical microscope probe and two-photon detection setup. The observed fringe period of 328.2 nm is well below the diffraction limit (351 nm = lambda /2). Another experiment with a path-length difference larger than the coherent length of photons confirms that the observed fringe is due to two-photon interference.
authors: Yoshio
authors: Y
authors: Kawabe
authors: Hideki
authors: H
authors: Fujiwara
authors: Ryo
authors: R
authors: Okamoto
authors: Keiji
authors: K
authors: Sasaki
authors: Shigeki
authors: S
authors: Takeuchi