Tailored Ion Beam for Precise Color Center Creation

TL;DR

This paper introduces a quantum control method for generating a monochromatic, low-dispersion ion beam from a Paul trap, enhancing precision in ion implantation without the need for sympathetic cooling.

Contribution

The authors develop a unitary quantum control scheme that produces a highly monochromatic ion beam with low dispersion, using simple voltage supplies and avoiding sympathetic cooling.

Findings

Achieves a low-dispersion ion beam with simple voltage control.

Enables control of ion energy and momentum spread.

Improves lateral resolution for ion implantation.

Abstract

We present a unitary quantum control scheme that produces a highly monochromatic ion beam from a Paul trap. Our protocol is implementable by supplying the segmented electrodes with voltages of the order of Volts, which mitigates the impact of fluctuating voltages in previous designs and leads to a low-dispersion beam of ions. Moreover, our proposal does not rely on sympathetically cooling the ions, which bypasses the need of loading different species in the trap -- namely, the propelled ion and, e.g., a $^{40}$Ca$^+$ atom able to exert sympathetic cooling -- incrementing the repetition rate of the launching procedure. Our scheme is based on an invariant operator linear in position and momentum, which enables us to control the average extraction energy and the outgoing momentum spread. In addition, we propose a sequential operation to tailor the transversal properties of the beam before the ejection to minimize the impact spot and to increase the lateral resolution of the implantation.