Directional electron acceleration on glass nanospheres. A femtosecond laser pulse (coming
from the left) hits a glass nanosphere. The light releases electrons (green) from the
group of atoms. Graphic: Martin Dulovits, woogieworks
A team of physicists and chemists from the Laboratory of Attosecond Physics at the Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics has studied the interaction of light with tiny glass particles.
(August 12, 2015) The relationship between strong laser pulses and glass nanoparticles is a special one – one that could influence medical methods, as scientists from Rostock, Munich, and Berlin have discovered. The interplay between light and matter was studied by a team of physicists and chemists from the Laboratory of Attosecond Physics (LAP) at the Max Planck Institute of Quantum Optics (MPQ) and the Ludwig-Maximilians-Universität Munich (LMU), from the Institute of Physics of the University of Rostock, and from the Freie Universität Berlin. The researchers studied the interaction between strong laser pulses and glass nanoparticles, which consist of multiple millions of atoms. Depending on how many atoms were contained in the nanoparticles, these objects reacted differently over attosecond timescales (an attosecond is a billionth of a billionth of a second). Depending on their size, so called near-fields (electromagnetic fields close to the particle surface) were induced by the laser pulses, resulting in a controlled directional emission of electrons. These findings could eventually extend cancer therapy and imaging methods in medicine. The study was published in the latest issue of the journal Nature Communications.
Strong laser pulses have an extremely pronounced effect on nanoparticles. As soon as the atoms “feel” the electromagnetic wave of the light, their electrons start to oscillate. This produces near-fields at the surface of the particles. These near-fields have dimensions in the nanometer range, and oscillate in a characteristic fashion depending on the wavelength of the incident light.