Ground state sideband cooling of an ion in a room temperature trap with a sub-Hertz heating rate

TL;DR

This paper reports on achieving near-perfect ground state cooling of a single ion in a room temperature trap with exceptionally low heating rates, surpassing previous results in similar conditions.

Contribution

It demonstrates resolved sideband laser cooling of a 40Ca+ ion in a large, room temperature RF trap with unprecedentedly low heating rates and high ground state population.

Findings

Achieved 99% ground state population of the ion.

Measured heating rates below one quantum per second at room temperature.

Lowest heating power reported for room temperature traps, surpassing previous cryogenic results.

Abstract

We demonstrate resolved sideband laser cooling of a single 40Ca+ ion in a macroscopic linear radio frequency trap with a radial diagonal electrode spacing of 7 mm and an rf drive frequency of just 3.7 MHz. For an oscillation frequency of 585 kHz along the rf-field-free axis, a ground state population of 99+-1% has been achieved, corresponding to a temperature of only 6 microkelvin. For several oscillation frequencies in the range 285 - 585 kHz, heating rates below one motional quantum per second have been measured at room temperature. The lowest measured heating power is about an order of magnitude lower than reported previously in room temperature, as well as cryogenically cooled traps.