This paper develops a method for estimating the locations of laser-induced stray charges on surface-electrode ion traps. How the electric potential at the trapped-ion location changes in the presence of laser-induced stray charges is theoretically modeled, and the magnitude of the shift in the secular frequency of a trapped ion is derived from the model. This model can be used inversely to find the locations of stray charges from the secular frequency shift under certain conditions. Typically, this inverse relationship is not unique. However, in surface-electrode ion traps, the secular frequency shift caused by the stray charges can be measured at multiple ion positions, and therefore, the required number of secular-frequency-shift measurements can be performed to determine the stray-charge locations uniquely. This model is experimentally evaluated by intentionally producing electric charges at a single location by irradiating a laser onto that spot and by measuring the resulting secular frequency shift. The location of produced charges is estimated from the measured result, and the estimated location is consistent with where the laser is irradiating. The developed method can be applied to characterize the laser-induced stray charges, which in turn can be used to design experiments to avoid or reduce the occurrence of stray charges.

• Received 13 December 2022
• Revised 19 May 2023
• Accepted 21 June 2023

DOI:https://doi.org/10.1103/PhysRevApplied.20.014032