Characterizing the spatial potential of an ion trap chip

Abstract

The accurate characterization of the spatial electric field generated by electrodes in a surface electrode trap is of paramount importance. In this pursuit, we have identified a simple yet highly precise parametric expression to describe the spatial field of a rectangular-shaped electrode. Leveraging this expression, we introduced an optimization method designed to accurately characterize the axial electric field intensity produced by the powered electrode and the stray field. Distinct from the existing methods, our approach integrates a diverse array of experimental data, including the equilibrium positions of ions in a linear string, the equilibrium positions of single trapped ions, and trap frequencies, to effectively reduce the systematic errors. This approach provides considerable flexibility in voltage settings for data acquisition, making it especially advantageous for surface electrode traps where the trapping height of ion probes may vary with casual voltage settings. In our experimental demonstration, we successfully minimized the discrepancy between observations and model predictions to a remarkable degree. The relative errors of secular frequencies were contained within ±0.5%, and the positional error of ions was constrained to less than 1.2 μm, which surpasses the performance of current methodologies.