First photo of atom's shadow at Qld uni

A university in Queensland has managed to photograph the shadow of an atom, an achievement that will make waves in the world of quantum computing.
Written by AAP , Contributor and  Suzanne Tindal, Contributor

A pixellated image of a black spot on an orange background isn't likely to win any photographic competitions.

The world-first image.
(Credit: Griffith University)

However, the seemingly bland image, taken by scientists at Queensland's Griffith University, could potentially revolutionise mankind's understanding of physics and how the world works.

A research team at the university's centre for quantum dynamics in Brisbane has been able to photograph the shadow of a single atom for the first time.

Professor Dave Kielpinski said that the image is at the extreme limit of microscopy.

"You cannot see anything smaller than an atom using visible light," Professor Kielpinski said in a statement.

"We wanted to investigate how few atoms are required to cast a shadow, and we proved it takes just one."

The scientists used a super high-resolution microscope not available anywhere else in the world.

A single atom of the element ytterbium was held by electrical forces and exposed to a specific frequency of light, which caused it to cast a shadow that could be photographed.

Research team member Erik Streed said that the photo has myriad implications, including revolutionising quantum computing and biomicroscopy.

"In quantum computing, light is the most effective method for communication, while atoms are often better for performing calculations," Streed said in a post on The Conversation.

"In observing the shadow from a single atom, we have shown how to improve the input efficiency in a quantum computer. Single atoms have well-understood light-absorption properties. We used this knowledge to predict how dark the shadow should be for a given amount of light."

In biomicroscopy, they can use the knowledge of how dark a single atom should be to measure whether the microscope is achieving the maximum contrast allowed by physics.

"This is important if you want to look at very small and fragile biological samples, such as DNA strands, where exposure to too much UV light or x-rays will harm the material," Streed said.

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