Measurement of ion displacement via RF power variation for excess micromotion compensation

TL;DR

This paper presents a precise method for minimizing ion micromotion in linear Paul traps by measuring ion displacement caused by stray electric fields through fluorescence imaging, suitable for compact and planar ion traps.

Contribution

The authors introduce a novel technique for micromotion compensation that does not depend on laser orientation, enabling its use in miniaturized and planar ion trap systems.

Findings

Achieved residual electric field uncertainty of a few volts per meter.

Method effective regardless of laser orientation or detuning.

Applicable to various trap geometries for sensing and metrology.

Abstract

We demonstrate a method of micromotion minimization of a trapped ion in a linear Paul trap based on the precision measurement of the ion trapping position displacement due to a stray electric field in the radial plane by ion fluorescence imaging. The amount of displacement in the radial plane is proportional to the strength of a stray electric field. Therefore, we evaluated the micromotion compensation condition by measuring the ion displacements from the ion equilibrium position using two different radial trap frequencies with various combinations of the compensation voltage. The residual electric field uncertainty of this technique reached a few volts per meter. This compensation technique does not depend on the orientation of the incident cooling laser or the detuning and imaging direction. Therefore, this method is suitable for a planar ion trap, a stylus ion trap, which limits the propagation angle of lasers, or miniaturized ion trap systems for sensing and metrological applications.