A Fast, Deterministic Source of Cr Atoms

Overview

As nanotechnology moves toward manipulating matter at finer and finer levels, we are led to the ultimate concept of controlling individual atoms one at a time, deciding exactly when and where we want them. To explore ways in which atom optics can be used to approach this goal, we have developed a highly deterministic source that can eject single atoms essentially "on demand" whenever they are needed. In concept, we have a "black box" source that can accept arbitrary electronic demand pulses (e.g. TTL pulses) and reliably produce one, and only one, atom for each pulse.

Figure 1. Schematic showing TTL pulses triggering a "black box" to produce single atoms.

Such a source is not only relevant to the ultimate nanotechnology goal of atom-by-atom control. It is also useful for a number of emerging technologies and avenues of scientific study that are beginning to exploit purely quantum processes. Foremost among these is the rapidly expanding field of quantum information processing. Further applications include quantum electrodynamics studies of single atoms in cavities, precision doping of semiconductor nanostructures for novel photonic materials, and detailed collision studies of two or three atoms at a time.

Our deterministic source [EPG Pub #739] consists of a magneto-optical trap (MOT), in which we detect atomic fluorescence with sufficiently high efficiency to easily discriminate between zero, one, or more atoms in the trap. The fluorescence signal is then used to control loading and dump gates: if the signal reaches the one-atom level, loading is turned off, and if the signal ever reaches the two- (or more) atom level, the trap is dumped. The result of this feedback control is a trap that contains one, and only one, atom up to 99% of the time.

Summary

• By actively controlling the loading and loss processes, we have demonstrated a magneto-optical trap containing a single atom 98.7% of the time.
• We have periodically ejected single atoms with 90% confidence at 10 Hz.
• Simulations predict single-atom extraction with 99% confidence at rates approaching 400 Hz.

Online: May 2003
Last Updated: February 2008

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