The resolution of optical scanning microscopes is limited by the spot size of the scanning beam. It has been proposed by Boto1 et al. and Nasr2 et al. that momentum entangled photons can be focused more tightly than classical light. Thus they should enable one to break the di ractive resolution limit. We report experiments measuring the spatial distribution of strong focussed momentum entangled photon pairs at a center wavelength of 812 nm from a spontaneous parametric down conversion source. Using a single gold stripe deposited on a glass surface as test object we observe a two-photon spot size as small as 194 nm, thereby beating the di raction limit even for conventional two-photon microscopy.

Date Published: 26 September 2013
PDF: 7 pages
Proc. SPIE 8875, Quantum Communications and Quantum Imaging XI, 887509 (26 September 2013); doi: 10.1117/12.2023010

Published in SPIE Proceedings Vol. 8875:
Quantum Communications and Quantum Imaging XI
Ronald E. Meyers; Yanhua Shih; Keith S. Deacon, Editor(s)