Controlling free electrons -- from attosecond physics at nanotips via photonic accelerators to quantum-enhanced electron microscropy

29.11.2013, 14:00

Prof Dr Peter Hommelhoff, Department of Condensed Matter Physics, FAU

Electro-magnetic control of electrons is of utmost interest in many applications, ranging from electron microscropes to particle accelerators. With laser-based techniques, we are exploring fundamentally new ways to steer electrons. Three experiments will be sketched: 1. At nanoscale tips, we have observed that electrons, photo-emitted by phase-controlled few-cycle laser pulses, can be steered back to the parent tip, where they re-collide with the tip's surface. All this happens wihtin a single cycle of a laser period and forms the basis of attosecond physics -- here observed at a solid. Implications for ultrafast nanooptics and plasmonics will be presented. 2. In free space electrons can not be efficiently accelerated with oscillating fields. This notion does not hold any more if a properly chosen boundary is present. We show that with dielectric optical gratings, acceleration of electrons with laser light works. Much larger gradients (GeV/m) than in today's accelerators are possible. 3. In the third experiment, we investigate if an electron microscope can be built that allows imaging of alive biological samples. This can only work if the radiation dose needed for imaging can be drastically reduced. We will present quantum enhanced electron imaging techniques. With our demonstration of a planar microwave Paul trap for electrons, we have taken a first steps in this direction.