Researchers from the HUN-REN Wigner Research Centre for Physics have conducted laser experiments that vividly demonstrate the dual nature of light. When laser light interacts with nanoparticles, it generates electrons while behaving as both a particle and a wave. This work, published in the prestigious journal Physical Review Letters, also included contributions from the ELI-ALPS Laser Research Institute in Szeged.
In their experiments in Budapest, physicists at the HUN-REN Wigner Research Centre for Physics used femtosecond (10-15 second) laser pulses to eject electrons from gold nanoparticles and measured their kinetic energy. By fine-tuning the intensity of the laser light, they identified a range where the laser primarily acts as particles on the electrons, a phenomenon known as multiphoton emission. However, at the same intensity, they also observed electrons behaving differently, affected by the laser light as electromagnetic waves—these are known as rescattered electrons.
“The beauty of this infrared laser-based experiment was that we could clearly observe both behaviours of light within a single experiment,” summarised Péter Dombi, leader of the Ultrafast Nano-optics Research Group at the Wigner RCP. Balázs Bánhegyi, a PhD student and lead author of the paper, added, “This result also shows that in basic research, if we look deep enough, we can always discover something new, even about physical processes we believed were fully understood, which provides strong motivation to continue our work.”
A physicist at the HUN-REN Wigner Research Centre for Physics sets up a femtosecond laser
(Photo: Márton Kovács)
The results of the Budapest researchers were published in the prestigious journal Physical Review Letters. The Nanofabrication Laboratory at the ELI-ALPS Laser Research Institute also contributed to the experiments by producing specifically designed nanoparticles.