Reduction of heating rate in a microfabricated ion trap by pulsed-laser cleaning

Laser cleaning of the electrodes in a planar micro-fabricated ion trap has been attempted using ns pulses from a tripled Nd:YAG laser at 355 nm.The effect of the laser pulses at several energy density levels has been tested by measuring the heating rate of a single 40 Ca + trapped ion as a function of its secular frequency ω z .A reduction of the electric-field noise spectral density by ∼50% has been observed and a change in the frequency dependence also noticed.This is the first reported experiment where the 'anomalous heating' phenomenon has been reduced by removing the source as opposed to reducing its thermal driving by cryogenic cooling.This technique may open up the way to better control of the electrode surface quality in ion microtraps.The recent success of quantum information experiments based on trapped ions [1] triggered research on micro-fabricated radio-frequency (Paul) traps, which are in principle able to fulfill the scalability requirement of a quantum computer [2,3].In such traps, a set of micro-fabricated conducting electrodes generates oscillating and static electric fields that trap laser-cooled ions in a harmonic potential well at a sub-millimeter distance d from the substrate [4,5].However, the presence of uncontrolled fluctuating electric fields affects the ions' external motion and induces an 'anomalous heating' that limits the achievable fidelity of multi-ion quantum gates that rely on the coherent control of this motion [6].Experimental observations concerning this phenomenon