Optical frequency measurement and ground state cooling of single trapped Yb⁺ions.

J. Mielke

High precision comparisons of the proton and antiproton g-factor enable stringent tests of CPT symmetry in the baryonic sector. However, current measurement routines suffer from long preparation times and high particle temperatures, which complicate the increase of the precision beyond the parts per billion regime. As a solution, new sympathetic cooling schemes based on co-trapped laser-cooled ions may be used to cool (anti-)protons to the ground state of motion and to significantly decrease particle preparation times. In addition, motional coupling to an auxiliary ion in a double-well potential can be used for the implementation of new readout schemes based on quantum logic spectroscopy for the spin-state of the (anti-)protons. This thesis describes a cryogenic Penning trap system for ground state cooling of single 9Be+ ions, which represents the latest development of the BASE experiment in Hannover towards the implementation of sympathetic cooling schemes and quantum logic spectroscopy of single (anti-)protons. Furthermore, the setup and implementation of lasers systems at 313nm for Doppler cooling, repumping and Raman interactions are described. To this end, an optical platform for laser beam delivery to the vacuum system and an optical phase-locked loop for the stabilization of the relative phase of two lasers at 313 nm are presented. In this work, the laser systems are used for measurements of the optical resonance frequencies for cooling, probing and repumping of 9Be+ ions. In addition, stimulated Raman transitions are demonstrated using two phase-locked lasers at 313nm. In the following, this technique is used for high-precision measurements of the qubit frequency and the magnetic field, as well as themometry measurements with 9Be+ ions. The temperature of the ions after Doppler cooling is measured as a function of the cooling laser parameters and a minimal axial mode temperature of 1.77(10) mK is obtained. The results of this thesis pave the way for sideband spectroscopy and ground state cooling of single 9Be+ ions in Penning traps, which is an essential prerequisite for sympathetic ground state cooling of single (anti-)protons and the application of quantum logic spectroscopy to (anti-)proton g-factor measurements in the future.

G. P. Barwood, A.S. Bell, Patrick Robert Gill +1 more

Yujiro Eto, Atsushi Noguchi, Peng Zhang +2 more

Ilya A. Semerikov, Ksenia Yu. Khabarova, Ilia V. Zalivako +2 more

The schematic diagram of the compact transportable optical frequency standard based on the quadrupole transition in a single 171 Yb + ion with a relative instability at the levelx of 5 · 10 −16 , less than 1m 3 in volume and less than 300 kg in weight is presented. The ionic trap and laser systems are described. Trapping and laser cooling of the 174 Yb + ion are experimentally demonstrated.

H. Arthur Klein, A.S. Bell, G. P. Barwood +1 more

Clément Lacroûte, Maël Souidi, Pierre-Yves Bourgeois +6 more

We present the design of a compact optical clock based on the 2 S 1/2 → 2 D 3/2 435.5 nm transition in 171 Yb + . The ion trap will be based on a micro-fabricated circuit, with surface electrodes generating a trapping potential to localize a single Yb ion a few hundred μ m from the electrodes. We present our trap design as well as simulations of the resulting trapping pseudo-potential. We also present a compact, multi-channel wavelength meter that will permit the frequency stabilization of the cooling, repumping and clear-out lasers at 369.5 nm, 935.2 nm and 638.6 nm needed to cool the ion. We use this wavelength meter to characterize and stabilize the frequency of extended cavity diode lasers at 369.5 nm and 638.6 nm.