Description
Towards Feedback Cooling of a Single Trapped Ion in a Deep Parabolic Mirror
Atish Roy$^{1}$, Martin Fischer$^{1}$, Hans Dang$^{1,2}$, Lakhi Sharma$^{1}$, Markus Sondermann$^{2,1}$ and Gerd Leuchs$^{1,2,3,4}$
$^1$Max Planck Institute for the Science of Light, Erlangen, Germany
$^2$Friedrich-Alexander Universität Erlangen-Nürnberg, Department of Physics, Erlangen, Germany
$^3$Department of Physics, University of Ottawa, Canada
$^4$Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
Email: atish.roy@mpl.mpg.de
In applications in quantum technologies as well as in many experimental scenarios, the residual thermal motion of a trapped and laser cooled ion has detrimental effects, e.g. a reduction of the coupling to tightly focused light fields [1]. One possible method to cool the ion beyond the Doppler limit is feedback cooling [2]. Here, we apply feedback cooling in a set-up based on a deep parabolic mirror, exploiting the mirror's large collection efficiency [3]. The fluorescence signal collected by the parabolic mirror
Fig 1: Schematic of experimental setup for direct detection of secular motion of ion, L: Lens, PM: Parabolic Mirror, f: focal length.
contains information of the position of the ion in its phase front. Upon Fourier transformation by a lens, this information is transformed to an intensity distribution with a shape and position governed by the shift of the ion off the focus of the parabolic mirror. Changes to this intensity distribution are measured using a knife edge and a photo multiplier tube (see Fig.1), enabling direct detection of the secular motion of the ion. The detected signal is used to produce a feedback signal that is applied to one of the electrodes of the trap assembly. The phase and gain of this signal determines the amplitude of the feedback cooled ion's secular motion. We report on our progress towards lowering the ion's temperature below the limit set by Doppler cooling [4].
[1]. Martin Fischer, et al., "Shifting the phase of a coherent beam with a $^{174}$ Yb$^+$ ion: influence of the scattering cross section," Appl. Phys. B. 123, 48 (2017).
[2]. Pavel Bushev, et al.,"Feedback Cooling of a Single Trapped Ion," Phys. Rev. Lett. 96, 043003 (2006).
[3]. Robert Maiwald, et al.,"Collecting more than half the fluorescence photons from a single ion," Phys. Rev. A. 86, 043431 (2012).
[4]. Bharat Srivathsan, et al., "Measuring the temperature and heating rate of a single ion by imaging," New. J. Phys. 21, 113014 (2019).
| Presenter name | Atish Roy |
|---|---|
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