Science News
“The world's fastest cameras captures motion of electrons”
Date : 04-Feb-2019
Film recordings show for the first time how the energy distribution in a graphite sample changes in the ultrashort period of 50 femtoseconds.
Credit: Phys. Rev. Lett
The special feature of the Kiel system is its extremely high temporal resolution of 13 femtoseconds. This makes it one of the fastest electron cameras in the world.
In their current research experiment, the research team irradiated a graphite sample with a short, intense light pulse of only seven femtoseconds duration. Graphite is characterized by a simple electronic structure. Thus, fundamental processes can be observed particularly clearly. In the experiment, the impacting light particles—also called photons—disturbed the thermal equilibrium of the electrons. This equilibrium describes a condition in which a precisely-definable temperature prevails amongst the electrons. The Kiel research team then filmed the behavior of the electrons, until a balance was restored after about 50 femtoseconds.
Reference : G. Rohde et al, Ultrafast Formation of a Fermi-Dirac Distributed Electron Gas, Physical Review Letters (2018).DOI: http://10.1103/PhysRevLett.121.256401