Sideband cooling of small ion Coulomb crystals in a Penning trap
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
We have recently demonstrated the laser cooling of a single 40 Ca + ion to the motional ground state in a Penning trap using the resolved-sideband cooling technique on the electric quadrupole transition S 1/2 ↔ D 5/2 . Here we report on the extension of this technique to small ion Coulomb crystals made of two or three 40 Ca + ions. Efficient cooling of the axial motion is achieved outside the Lamb-Dicke regime on a two-ion string along the magnetic field axis as well as on two- and three-ion planar crystals. Complex sideband cooling sequences are required in order to cool both axial degrees of freedom simultaneously. We measure a mean excitation after cooling of n COM for the centre of mass (COM) mode and n B for the breathing mode of the two-ion string with corresponding heating rates of 11(2)s -1 and 1(1)s -1 at a trap frequency of 162 kHz. The occupation of the ground state of the axial modes (n tilt = n COM = 0) is above 75% for the two-ion planar crystal and the associated heating rates 0.8(5)s -1 at a trap frequency of 355 kHz.
Date Issued
2017-10-24
Date Acceptance
2017-08-25
Citation
Journal of Modern Optics, 2017, 65 (1), pp.64-74
ISSN
0950-0340
Publisher
Taylor & Francis
Start Page
64
End Page
74
Journal / Book Title
Journal of Modern Optics
Volume
65
Issue
1
Copyright Statement
This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Modern Optics on 24 Oct 2017, available online at: http://www.tandfonline.com/10.1080/09500340.2017.1376719
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Commission of the European Communities
Engineering & Physical Science Research Council (EPSRC)
Grant Number
GR/R14415/01
EP/D068509/1
249958
N/A
Subjects
quant-ph
0205 Optical Physics
0206 Quantum Physics
1007 Nanotechnology
Optics
Publication Status
Published