A student from the University of Oxford has won the 2018 Science Photography Competition organized by the United Kingdom’s Engineering and Physical Sciences Research Council; his amazing entry shows a single atom of strontium, the alkaline earth metal classified as number 38 in the periodic table. The atom in the photograph, which was captured by an inexpensive digital camera found in most electronics stores, appears in the middle of two electrodes emitting an invisible electric field that keeps the atom afloat.
The atom was isolated within a vacuum chamber storing a device known as an ion trap. The strontium atom was trapped between two electrodes situated about two millimeters apart. In the photograph, the atom appears right in the middle of the electrodes, and it is clearly visible when the size of the high resolution image is expanded.
To capture this unique shot, scientists at the atomic lab pointed a laser that displays a blue and violet glow. Knowing that strontium is an elements that absorbs and reflects light particles, the photographer set up his camera to take long exposure images; the idea came to him after learning about the lighting tricks used by scientists to visualize atomic activity. After thinking about different methods he could use to bridge the quantum and everyday worlds, the photographer drafted some calculations that seemed promising. The equipment used included a standard camera, a tripod and a timer; it took a single afternoon and a few takes to get the photograph just right.
To get an idea of the incredibly small size of the atom at the center of the award-winning photograph, it helps to imagine that more than a billion atoms can fit inside a red blood cell; in turn, a million cells can easily be glimpsed inside a drop of blood when placed under a microscope.
When looking at the photograph, viewers should keep in mind that they are not actually looking at the atom itself, which is invisible to the naked eye; they are looking at light particles reflected off a single atom.