NAWI Graz researchers measure light fields in 3D

Researchers from TU Graz and the University of Graz present the new method of 3D-plasmon tomography in Nature Communications. Light as a carrier of information is indispensable to modern communication technology. The controlled manipulation of light quanta, so-called photons, form the basis for wireless transmission or data transfer in optical glass fibres. Due to the wave-like nature of light and its diffraction limit, however, optical components can only focus light down to the micron scale (10-6 m). Ulrich Hohenester from the Institute of Physics at the University of Graz explains: "To enable photons and nanostructures to interact more efficiently, in the research field of plasmonics, we couple light onto a metallic nanoparticle, typically made out of gold or silver." Depending on size, shape, environment and material, resonating clouds of electrons are formed - so-called surface plasmons. Hohenester continues: "This collective electron vibration enables us to focus light at the nano scale and so use a variety of applications in sensor technology and photovoltaics." Imaging plasmon fields. The direct observation of plasmon fields is only possible thanks to Austria's most powerful electron microscope - the ASTEM, Austrian Scanning Transmission Electron Microscope, at the Graz Centre for Electron Microscopy.