Absorption imaging of a single atom

TL;DR

This paper demonstrates the first absorption imaging of a single atom in vacuum, achieving near-theoretical maximum contrast, with implications for quantum information processing and imaging light-sensitive samples.

Contribution

It presents the first successful absorption imaging of a single atom, using a phase Fresnel lens and achieving maximum contrast limited by resolution.

Findings

Achieved 3.1% image contrast for a single atom

Used a phase Fresnel lens for near-wavelength resolution

Results have implications for quantum information and imaging sensitive samples

Abstract

Absorption imaging has played a key role in the advancement of science from van Leeuwenhoek's discovery of red blood cells to modern observations of dust clouds in stellar nebulas and Bose-Einstein condensates. Here we show the first absorption imaging of a single atom isolated in vacuum. The optical properties of atoms are thoroughly understood, so a single atom is an ideal system for testing the limits of absorption imaging. A single atomic ion was confined in an RF Paul trap and the absorption imaged at near wavelength resolution with a phase Fresnel lens. The observed image contrast of 3.1(3)% is the maximum theoretically allowed for the imaging resolution of our setup. The absorption of photons by single atoms is of immediate interest for quantum information processing (QIP). Our results also point out new opportunities in imaging of light-sensitive samples both in the optical and x-ray regimes.