Using a stroboscope and laser, a team led by Swedish researcher Johan Mauritsson, assistant professor in atomic physics at Lund University, went beyond measuring the end result of an electron's interaction, they tracked and filmed its process.
The movie of electron motion was created by a collaboration of scientists at Lund, Louisiana State University, and the Institute for Atomic and Molecular Physics in Amsterdam. Their method involved using a stroboscope and a laser that uses attosecond pulses to film electron motion. Attosecond pulses are a new technology that generate short pulses from intense laser light. An attosecond is equal to 1/1000000000000000000th of a second (that’s 18 zeroes in the denominator).
The development must have sparked interest and debate at university physics and electrical engineering departments worldwide. Until now it has been impossible to photograph electrons, given their velocity of movement.
The Heisenberg Uncertainty Principle is a concept in quantum physics that makes the idea of "seeing" an electron interesting. The Heisenberg Uncertainty Principle states that it's impossible to know where a particle is located exactly, and how fast it is moving exactly, simultaneously.
That may be part of the reason why the group in Sweden needed to repeat the same interaction between an electron and an attosecond pulse several times and obtain many "snapshots." It isn't possible to watch a single electron along every step in its path.
The research draws from concepts in atomic and molecular physics, advanced optics, nonlinear optics and laser physics.
What are potential applications for the stroboscope and laser used to capture an electron’s collision with an atom?
“What we are doing is pure basic research. If there happen to be future applications, they will have to be seen as a bonus,” Mauritsson said.
J. Mauritsson, P. Johnsson, E. Mansten, et al. Coherent Electron Scattering Captured By an Attosecond Quantum Stroboscope, Phys. Rev. Lett. 100, 073003