In 2012, Australian physicists captured the first image of a single atom. The process was painstaking and required a super-high resolution microscope. The resulting image was groundbreaking, but not much to look at.
A new photograph taken by Oxford University physics PhD candidate David Nadlinger shows a single, glowing-blue strontium atom hovering within a powerful vacuum chamber. Taken using only an ordinary digital camera, Nadlinger’s image is equally remarkable, yet also quite beautiful – qualities that earned it the top prize in the 2018 Engineering and Physical Sciences Research Council (EPSRC) photography competition.
“Single Atom in an Ion Trap” allows us to visualize a single atom with the naked eye, yet what we are really looking at is blue light that was emitted by the atom and then absorbed by the camera's sensors during a long-exposure photo. The charged strontium atom is being held in place by electric fields emanating from the metal electrodes placed about 2 millimeters apart on either side. A window into the ion trap vacuum chamber provided a viewpoint for the camera's lens.
“The idea of being able to see a single atom with the naked eye had struck me as a wonderfully direct and visceral bridge between the minuscule quantum world and our macroscopic reality,” Nadlinger told the EPSRC.
“A back-of-the-envelope calculation showed the numbers to be on my side, and when I set off to the lab with camera and tripods one quiet Sunday afternoon, I was rewarded with this particular picture of a small, pale blue dot.”
Nadlinger already had all the equipment he would need, apart from his camera, because his lab uses this equipment to study the quantum state of matter, physical interactions at or below the atomic scale. This realm of existence defies our current grasp of physics, yet even our limited understanding was fundamental to the past development of telecommunication and timekeeping technology. More recent insights are responsible for sparking the ongoing revolution in computing that will likely change the course of human civilization. So, yeah, sort of important.
To observe the actions of a single atom, the particle must first be immobilized. Lasers come into play because atoms change velocity after absorbing and re-emitting light. And as temperature is actually a measurement of motion, physicists refer to the efficiency of this process in degrees Kelvin rather than terms of motion. Hence the technique's unimaginative name: Laser cooling.
Nadlinger's stunning representation of quantum research earned him the top spot out of more than 100 entries, all from groups who receive EPSRC funding.
Winners in the competition’s other five categories – Eureka & Discovery, Equipment & Facilities, People & Skills, Innovation, and Weird & Wonderful – can be seen here.