Stuttgart 2012 – wissenschaftliches Programm
Q 34.75: Poster
Dienstag, 13. März 2012, 16:30–19:00, Poster.I+II
Towards High Precision Laser Spectroscopy and Ground-State Cooling of a Mixed Species Coulomb Crystal — •David-M. Meier1, Jonas Keller1, Karsten Pyka1, Kristijan Kuhlmann1, and Tanja E. Mehlstäubler1,2 — 1Quest-Institute, Physikalisch-Technische Bundesanstalt — 2Department of Time & Frequency, Physikalisch-Technische Bundesanstalt, Braunschweig
The investigation of trapped ion Coulomb crystals is an active topic in the field of optical clocks, quantum sensors and quantum logic.
In our experiment we use 172Yb+ ions in laser cooled Coulomb crystals to sympathetically cool 115In+ to realize an optical frequency standard with indium ions as clock ions. We set up an ultra-stable laser at 411nm to perform ground-state cooling on the forbidden 2S1/2 to 2D5/2 quadrupole transition of 172Yb+. This laser will enable precise measurements of the crystal temperature and heating rates, the study of the mode structure and systematic shifts in such a clock.
We present the experimental set-up of our sub-Hz linewidth laser (fractional frequency instability 6× 10−16) at 822nm stabilized on a high-finesse ULE® cavity of 12cm length, which is frequency doubled with PPKTP in a bow-tie enhancement cavity. An output power of 24mW at 411nm out of 60mW IR was realized. Coulomb crystals with many ions display a complex mode-structure, which makes sideband-cooling and spectroscopy more difficult. We report on the calculations of radial and axial mode frequencies for a mixed ion species (115In+/172Yb+) crystal and discuss our scheme for ground-state cooling.