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.