Endcap-Type Paul Trap for Precision Spectroscopy and Studies of Controlled Interactions

TL;DR

This paper introduces a novel endcap-type Paul trap optimized for precision spectroscopy and controlled ion interactions, detailing its design, fabrication, and characterization for use with Ca$^{+}$ and Yb$^{+}$ ions.

Contribution

The paper presents a new trap design with detailed fabrication and characterization, enabling high-precision ion trapping and control for advanced quantum experiments.

Findings

Quadrupole coefficient close to design value (~0.3)

Minimal excess micromotion frequency shift (~3.5×10^{-18})

High-resolution imaging system with diffraction-limited performance

Abstract

We present the design and fabrication of an endcap-type Paul trap. The trap is designed for studies with Ca$^{+}$ and Yb$^{+}$. The design, fabrication process, and characterization are presented in detail with a focus on trapping a single compensated ion at the rf node. A custom-built imaging system of $NA = 0.14$ and magnification $\approx 22 \times$ performs close to diffraction-limit and resolves multi-ion clusters. Controlled ion loading and characterization of the trap are performed using $^{40}$Ca$^{+}$. The experimentally determined quadrupole coefficient of the trap is $\approx 0.3$, which is very close to the design value. The relative frequency shift along the spectroscopy beam due to excess micromotion (EMM) is at the level of $3.5\times 10^{-18}$ for $^{40}$Ca$^{+}$. Applications of this trap encompass single-ion-based optical frequency standards, tests of fundamental physics, the study of mesoscopic Coulomb clusters, and the controlled interaction of a single ion with co-trapped atoms.