Laser technology has advanced to a stage where we can generate pulses of light on timescales equivalent to those governing the dynamics of electrons within atoms and molecules. Two reports in this issue illustrate progress towards exploiting this capability to study and control the electronic properties and behaviour of such systems. The work by Inigo Sola and co–workers modulates the polarization of a train of ultrashort pulses to steer the return of an electron wavepacket to an atom from which it had been ionized. As a result, an isolated and much shorter secondary pulse emerges, towards the few–attosecond limit. Thomas Remetter and colleagues use a sequence of attosecond pulses to shear apart multiple electron wavepackets within an argon atom. By probing the subsequent interference between these wavepackets, valuable information about their phase is gained.

Letter by Sola et al | Letter by Remetter et al | News and Views by Thomas Pfeifer