title: Laser spectroscopy on forbidden transitions in trapped highly charged Ar(13+) ions.
abstract: We demonstrate resonant fluorescence laser spectroscopy in highly charged ions (HCI) stored in an electron beam ion trap by investigating the dipole-forbidden 1s(2)2s(2)2p (2)P(3/2)-(2)P(1/2) transition in boronlike Ar(13+) ions. Forced evaporative cooling yielded a high resolving power, resulting in an accurate wavelength determination to λ=441.255 68(26)  nm. By applying stronger cooling and two-photon excitation, new optical frequency standards based upon ultrastable transitions in such HCI could be realized in the future, e.g., for the search of time variations of the fine-structure constant.
authors: Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany. maeckel@mpi-hd.mpg.de
authors: V
authors: V
authors: Mäckel
authors: R
authors: R
authors: Klawitter
authors: G
authors: G
authors: Brenner
authors: J R
authors: JR
authors: Crespo López-Urrutia
authors: J
authors: J
authors: Ullrich