title: 0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography.
abstract: Quantum information technologies harness the intrinsic nature of quantum theory to beat the limitations of the classical methods for information processing and communication. Recently, the application of quantum features to metrology has attracted much attention. Quantum optical coherence tomography (QOCT), which utilizes two-photon interference between entangled photon pairs, is a promising approach to overcome the problem with optical coherence tomography (OCT): As the resolution of OCT becomes higher, degradation of the resolution due to dispersion within the medium becomes more critical. Here we report on the realization of 0.54 μm resolution two-photon interference, which surpasses the current record resolution 0.75 μm of low-coherence interference for OCT. In addition, the resolution for QOCT showed almost no change against the dispersion of a 1 mm thickness of water inserted in the optical path, whereas the resolution for OCT dramatically degrades. For this experiment, a highly-efficient chirped quasi-phase-matched lithium tantalate device was developed using a novel 'nano-electrode-poling' technique. The results presented here represent a breakthrough for the realization of quantum protocols, including QOCT, quantum clock synchronization, and more. Our work will open up possibilities for medical and biological applications.
authors.affiliation: Department of Electronic Science and Engineering, Kyoto University, Kyoto daigaku-katsura, Nishikyo-ku, Kyoto, Japan.|Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido, Japan.|The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Okano
authors.affiliation: National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, Japan.
authors.forename: Hwan Hong
authors.initials: HH
authors.lastname: Lim
authors.affiliation: Department of Electronic Science and Engineering, Kyoto University, Kyoto daigaku-katsura, Nishikyo-ku, Kyoto, Japan.|Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido, Japan.|The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Okamoto
authors.affiliation: Department of Quantum Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Nishizawa
authors.affiliation: National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, Japan.
authors.forename: Sunao
authors.initials: S
authors.lastname: Kurimura
authors.affiliation: Department of Electronic Science and Engineering, Kyoto University, Kyoto daigaku-katsura, Nishikyo-ku, Kyoto, Japan.|Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido, Japan.|The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Takeuchi