Cover Picture: Tomographic Reconstruction of Designer Free-Electron Wave Packets (ChemPhysChem 7/2013)



original image

Designer electron wave packets are created by multiphoton ionization of potassium atoms employing polarization-shaped femtosecond laser pulses, as reviewed on p. 1341 by M. Wollenhaupt et al. In order to reconstruct the three-dimensional photoelectron momentum distribution, we use a velocity-map imaging spectrometer to measure multiple projections at different angles by rotating the pulse with a l/2 plate. This procedure is illustrated for elliptically polarized light in the lower row. The images along the arrows (top left) show the evolution of measured projections towards a prescribed target (T) during an iterative optimization of the polarization-shaped pulse.

Cartoon 1.