Autoren:	Li, Wenbing Wolf, Sebastian Klein, Lukas Budker, Dmitry Düllmann, Christoph E. Schmidt-Kaler, Ferdinand
Titel:	Robust polarization gradient cooling of trapped ions
Online-Publikationsdatum:	6-Feb-2024
Erscheinungsdatum:	2022
Sprache des Dokuments:	Englisch
Zusammenfassung/Abstract:	We implement three-dimensional polarization gradient cooling (PGC) of trapped ions. Counter-propagating laser beams near 393 nm impinge in lin ⊥ lin configuration, at a frequency below the S1/2 to P3/2 resonance in 40Ca+. Our measurements demonstrate that cooling with laser beams detuned to lower frequencies from the resonance is robust against an elevated phonon occupation number and works continuously in the crossover from regular Doppler cooling to detunings of tens of linewidths. It is thus robust against heating events and also works well for an initial ion motion far out of the Lamb–Dicke regime. We show that PGC performance strongly depends on residual micromotion (MM) and find PGC working for a MM modulation index β ⩽ 0.1. Still, we find that the spectral impurity of the laser field affects both, cooling rates and cooling limits. Thus, a Fabry–Pérot cavity filter is employed to efficiently suppress amplified spontaneous emission of the diode laser. We demonstrate mean phonon numbers for a single ion of 5.4(4) at a trap frequency of 2π × 285 kHz and 3.3(4) at 2π × 480 kHz, in the axial and radial directions, respectively.
DDC-Sachgruppe:	530 Physik 530 Physics
Veröffentlichende Institution:	Johannes Gutenberg-Universität Mainz
Organisationseinheit:	FB 08 Physik, Mathematik u. Informatik Helmholtz Institut Mainz
Veröffentlichungsort:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-10060
Version:	Published version
Publikationstyp:	Zeitschriftenaufsatz
Weitere Angaben zur Dokumentart:	Scientific article
Nutzungsrechte:	CC BY
Informationen zu den Nutzungsrechten:	https://creativecommons.org/licenses/by/4.0/
Zeitschrift:	New journal of physics 24 4
Seitenzahl oder Artikelnummer:	043028
Verlag:	IOP
Verlagsort:	London
Erscheinungsdatum:	2022
ISSN:	1367-2630
DOI der Originalveröffentlichung:	10.1088/1367-2630/ac6233
Enthalten in den Sammlungen:	DFG-491381577-G