First Photo of Individual Atoms Floating

A few cesium atoms are trapped 270 nm away from the surface of an optical nanofiber. They are exposed to a near-resonant excitation laser field. (Source: HU)

Scientists at Humboldt University of Berlin (HU) and Technical University of Vienna (TU) have now succeeded for the first time in taking photos of indi­vidual atoms floating less than a thousandth of a millimeter above a light-conduc­ting glass fiber. This allows effects such as the absorption and emission of light to be studied in the labora­tory in a much more controlled way than before. In addition, the knowledge gained will help to develop components for a new gene­ration of optical fiber networks.

About ten years ago, Arno Rauschen­beutel’s research group realized for the first time a novel atom-light interface in which several thousand atoms are trapped in the vicinity of special glass fibers as optical nanofibers. The atoms are captured with tweezers created by laser light only 0.2 micro­meters away from the glass fiber surface. At the same time, they are cooled with laser light to a tempera­ture of about one millionth of a degree above absolute zero.

Despite these extreme condi­tions, the researchers have recently even been able to carry out experiments with single fiber-coupled atoms. They took photo­graphs of the atoms and made short films of a few seconds duration. To do this, they used an ultra-sensitive camera and had to rigorously shield any ambient light. Thanks to the permanent cooling, the atoms remained so steady that the images could be exposed for almost half a second.

“Based on these results, we will be able to study the inter­action of light and matter extremely precisely, atom by atom”, says Philipp Schnee­weiss, a member of Rauschen­beutel’s team. Possible applications of this research include more effi­cient light sources and photo­sensitive elements, using indi­vidual atoms as probes to study the pro­perties of surfaces, and the optical processing of quantum information. (Source: HU Berlin)

Reference: Y. Meng et al.: Imaging and Localizing Individual Atoms Interfaced with a Nanophotonic Waveguide, Phys. Rev. Lett. 125, 053603 (2020); DOI: 10.1103/PhysRevLett.125.053603

Link: Institute of Physics, Humboldt-University Berlin, Berlin, Germany

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