title: Fiber-microsphere system at cryogenic temperatures toward cavity QED using diamond NV centers.
abstract: The coupling of a microsphere resonator to a tapered fiber was demonstrated at cryogenic temperatures (8 - 13 K) and investigated with a probe laser light whose frequency around the zero phonon line of nitrogen vacancy centers in diamond (638 nm). For this purpose, a liquid-helium-flow cryostat with a large sample chamber is developed and a resonance dip with a Q of 2 x 10(6) is observed. The resonance frequency and the coupling condition are found to be stable for a period of one hour.
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takashima
authors.forename: Takeshi
authors.initials: T
authors.lastname: Asai
authors.forename: Kiyota
authors.initials: K
authors.lastname: Toubaru
authors.forename: Masazumi
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Keiji
authors.initials: K
authors.lastname: Sasaki
authors.forename: Shigeki
authors.initials: S
authors.lastname: Takeuchi