Monolithic Segmented 3D Ion Trap for Quantum Technology Applications

TL;DR

This paper introduces a fused-silica monolithic 3D ion trap that achieves low heating, high optical access, and stable operation for heavy ions, advancing quantum technology applications.

Contribution

It presents a novel fused-silica monolithic segmented 3D Paul trap with high RF voltages, low heating, and excellent optical access, suitable for scalable quantum systems.

Findings

Radial motional heating as low as 1.1 quanta/sec at 3 MHz

Motional Ramsey coherence time of 95 ms for radial mode

Successful generation of a two-qubit Bell state with 99.3% parity contrast

Abstract

Monolithic three-dimensional (3D) Paul traps combine the high-precision microfabrication of two-dimensional (2D) chip traps with the deep trapping potentials and low heating rates characteristic of macroscopic 3D Paul traps, which are typically machined by traditional means and mechanically assembled. However, achieving low motional heating rates and optical access with a high numerical aperture (NA) while maintaining the high radio-frequency (RF) voltages required for trapping heavy ionic species, such as Yb$^{+}$ and Ba$^{+}$, remains a significant technical challenge. In this work, we present a fused-silica, monolithic segmented 3D Paul trap with an ion-electrode distance of 250 $\mu$m, and stable operation at high RF voltages. We benchmark the performance of the trap using Yb$^{+}$ ions, demonstrating axially homogeneous trapping potentials spanning over 200 $\mu$m about the axial center of the trap, high multi-directional optical access (up to 0.7 NA), and radial motional heating as low as $\dot{\bar n}=1.1 \pm 0.1 $ quanta/s at radial trap frequencies about 3 MHz near room temperature. Furthermore, we observe a motional Ramsey coherence time, ${T}_{2}$, of about 95 ms for the radial center-of-mass mode. We demonstrate the generation of a two-qubit Bell state with a parity contrast of ${99.3}^{+0.7} _{-1.5}$% with state preparation and measurement correction. These results establish fused-silica monolithic 3D Paul traps as a scalable, modular platform for quantum simulation, computation, metrology, and networking with heavy ionic species.