Surface-electrode ion trap with integrated light source

TL;DR

This paper demonstrates an integrated fiber-optic light source in a cryogenic surface-electrode ion trap, enabling precise laser delivery for quantum computing applications with minimized displacement and charging effects.

Contribution

It introduces a novel surface-electrode ion trap with an integrated optical fiber source, achieving precise beam alignment and characterizing charging effects at cryogenic temperatures.

Findings

Achieved fiber-ion displacement within 0.13 of the mode center.

Measured fiber-induced charging of about 10 V/m at 125 μW.

Observed charging and discharging time constants of 1.6 s and 4.7 s.

Abstract

An atomic ion is trapped at the tip of a single-mode optical fiber in a cryogenic (8 K) surface-electrode ion trap. The fiber serves as an integrated source of laser light, which drives the quadrupole qubit transition of $^{88}$Sr$^+$. Through \emph{in situ} translation of the nodal point of the trapping field, the Gaussian beam profile of the fiber output is imaged, and the fiber-ion displacement, in units of the mode waist at the ion, is optimized to within $0.13\pm0.10$ of the mode center despite an initial offset of $3.30\pm0.10$. Fiber-induced charging at $125 \mu$W is observed to be ${\sim}10$ V/m at an ion height of $670 \mu$m, with charging and discharging time constants of $1.6\pm0.3$ s and $4.7\pm0.6$ s respectively. This work is of importance to large-scale, ion-based quantum information processing, where optics integration in surface-electrode designs may be a crucial enabling technology.