title: Doppler Cooling Trapped Ions with a UV Frequency Comb.
abstract: We demonstrate Doppler cooling of trapped magnesium ions using a frequency comb at 280 nm obtained from a frequency tripled Ti:sapphire laser. A comb line cools on the 3s_{1/2}-3p_{3/2} transition, while the nearest blue-detuned comb line contributes negligible heating. We observe the cooling-heating transition and long-term cooling of ion chains with several sympathetically cooled ions. Spatial thermometry shows that the ion is cooled to near the Doppler limit. Doppler cooling with frequency combs has the potential to open many additional atomic species to laser cooling by reaching further into the vacuum and extreme ultraviolet via high-harmonic generation and by providing a broad bandwidth from which multiple excitation sidebands can be obtained.
authors.affiliation: Max-Planck-Institute for Quantum Optics Hans-Kopfermann-Straße 1, Garching 81789, Germany.
authors.forename: Josue
authors.initials: J
authors.lastname: Davila-Rodriguez
authors.affiliation: Max-Planck-Institute for Quantum Optics Hans-Kopfermann-Straße 1, Garching 81789, Germany.
authors.forename: Akira
authors.initials: A
authors.lastname: Ozawa
authors.affiliation: Max-Planck-Institute for Quantum Optics Hans-Kopfermann-Straße 1, Garching 81789, Germany.
authors.forename: Theodor W
authors.initials: TW
authors.lastname: Hänsch
authors.affiliation: Max-Planck-Institute for Quantum Optics Hans-Kopfermann-Straße 1, Garching 81789, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Udem