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Quantum Photonic Technology Beating the Classical Limit

Keiji Sasaki

Research Institute for Electronic Science, Hokkaido University

3:30 pm Thursday, 21 January 2010, EN101 (Ground Floor, EN Building), Hawthorn.

Quantum mechanically correlated photons, so called “entangled photons”, are expected to open new research fields in optical fabrication, microscopy, spectroscopy, data storage as well as information technology. In classical optics, spatial resolution of photolithography is limited by the Rayleigh diffraction. Widths of fabricated lines can be reduced by use of multi-photon processes, however, the minimum line separation is essentially limited to l/2 even for multi-photon lithography. Boto et al. theoretically proposed quantum lithography to overcome this diffraction limit. In this new technique, N-photon entangled state is used for reducing the resolution limit to l/2N. Recently, we succeeded in observation of reduced de Broglie wavelength of entangled four-photons in the time domain [1], and also demonstrated direct observation of spatially-formed interference fringes with the periods of smaller than l/2 [2]. In addition, we successfully developed an entanglement filter which works for extracting entangled photons from classical light sources [3]. In this seminar, we introduce recent results on these new quantum optical methodologies and their applications.

[1] T. Nagata et al., Science 316, 726 (2007).
[2] Y. Kawabe et al., Opt. Exp. 15, 14245 (2007).
[3] R. Okamoto et al., Science 323, 483 (2009).

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