title: Frequency down-conversion of 637 nm light to the telecommunication band for non-classical light emitted from NV centers in diamond.
abstract: We demonstrate a low-noise frequency down-conversion of photons at 637 nm to the telecommunication band at 1587 nm by the difference frequency generation in a periodically-poled lithium niobate. An internal conversion efficiency of the converter is estimated to be 0.44 at the maximum which is achieved by a pump power of 0.43 W, whereas a rate of internal background photons caused by the strong cw pump laser is estimated to be 9 kHz/mW within a bandwidth of about 1 nm. By using the experimental values related to the intrinsic property of the converter, and using the intensity correlation and the average photon number of a 637 nm input light pulse, we derive the intensity correlation of a converted telecom light pulse. Then we discuss feasibility of a single-photon frequency conversion to the telecommunication band for a long-distance quantum communication based on NV centers in diamond.
authors.forename: Rikizo
authors.initials: R
authors.lastname: Ikuta
authors.forename: Toshiki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Shuto
authors.initials: S
authors.lastname: Yasui
authors.forename: Shigehito
authors.initials: S
authors.lastname: Miki
authors.forename: Taro
authors.initials: T
authors.lastname: Yamashita
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Terai
authors.forename: Mikio
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masato
authors.initials: M
authors.lastname: Koashi
authors.forename: Masahide
authors.initials: M
authors.lastname: Sasaki
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Imoto