Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

TL;DR

This paper introduces a scalable CMOS-fabricated linear ion trap with advanced control electrodes and integrated features, enabling precise manipulation of ion chains for quantum computing.

Contribution

The paper presents a novel microfabricated ion trap design with 44 independently controlled electrodes, integrated capacitors, and optimized geometry for improved ion manipulation and reduced stray fields.

Findings

Verified trap potentials through experiments

Achieved stable trapping lifetimes and low heating rates

Successfully canceled stray electric fields for uniform ion chains

Abstract

Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled DC electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on DC electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains.