Accumulation of chromium metastable atoms into an Optical Trap

TL;DR

This paper demonstrates rapid accumulation of over a million metastable chromium atoms in an optical trap, achieving high density and low temperature, with optimized loading and measurement of light shifts.

Contribution

It introduces a method for fast accumulation of chromium metastable atoms in a combined optical and magnetic trap, with detailed analysis of light shifts and optimization procedures.

Findings

Achieved over one million metastable chromium atoms in 400 ms.

Reached a temperature of about 100 microKelvin.

Measured and analyzed the light shift of the 5D4 state.

Abstract

We report the fast accumulation of a large number of metastable 52Cr atoms in a mixed trap, formed by the superposition of a strongly confining optical trap and a quadrupolar magnetic trap. The steady state is reached after about 400 ms, providing a cloud of more than one million metastable atoms at a temperature of about 100 microK, with a peak density of 10^{18} atoms.m^{-3}. We have optimized the loading procedure, and measured the light shift of the 5D4 state by analyzing how the trapped atoms respond to a parametric excitation. We compare this result to a theoretical evaluation based on the available spectroscopic data for chromium atoms.