CQOM Seminar

Speaker:

Dr. Vincent Jarlaud, Imperial College, London, UK

Title:

Sideband Cooling of Ion Coulomb Crystals in a Penning Trap

Abstract:

In this talk I will present the progress made with laser cooling and coherent manipulation of calcium ions in the Penning trap of Imperial College London. Using resolved sideband cooling, we demonstrated ground state cooling of a single ion in a Penning trap for the first time in 2014 [1]. We are now able to perform ground state cooling of the axial motion over a wide range of trapping frequencies (~ 67 kHz to 450 kHz) with a high occupation probability. We also achieved near ground state cooling of the radial motion of a single ion with mean motional states below one for both the magnetron and modified cyclotron modes.

The sideband cooling technique has been extended to small numbers of ions arranged in one and two dimensional Coulomb crystals [2]. Near ground state cooling of 2D planar crystals made of up to ten ions is demonstrated and we are able to observe Rabi oscillations from the cold Coulomb crystals by exciting the S­_1/2 ? D_5/2 transition of calcium.

We also perform Ramsey experiments on a single ion by creating coherent superpositions of electronic and vibrational states in order to study the coherence of the optical qubit S­_1/2 ? D_5/2 and of the axial motion.

[1]: J.F. Goodwin et al. Resolved-sideband laser cooling in a Penning trap. PRL 116, 143002 (2016)

[2]: G. Stutter et al. Sideband cooling of small ion Coulomb crystals in a Penning trap. J. Mod. Opt. 65:1, 64-74 (2018)

Coffee and cake will be served at 11:00.