title: Dark-state imaging for two-dimensional mapping of a magnetic field.
abstract: By imaging the dark states that are due to coherent population trapping in Na atomic vapor, we have succeeded in depicting a spatially inhomogeneous magnetic field. Highly resolved dark lines represent cross sections of the surfaces of constant magnetic fields, and they agree well with the predicted hyperfine Zeeman splitting and the two-photon selection rules of the Na atom. Mapping was made two dimensionally in real time, but extension to three dimensions is straightforward. Furthermore, unlike the previous techniques based on optical pumping, this method can be used for any magnetic-field directions.
authors.affiliation: Department of Physics, Faculty of Science, Kumamoto University, 2-39-1 Kurokami, Kumamoto-shi, Kumamoto 860-8555, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Asahi
authors.forename: Koji
authors.initials: K
authors.lastname: Motomura
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Harada
authors.forename: Masaharu
authors.initials: M
authors.lastname: Mitsunaga