Quantum interference fringes beating the diffraction limit.
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.
Kawabe
Yoshio
Y
Fujiwara
Hideki
H
Okamoto
Ryo
R
Sasaki
Keiji
K
Takeuchi
Shigeki
S