Figure legend, Fig. 2: Generation of attosecond laser pulses at the Max Planck Institute for Quantum Optics: A femtosecond laser pulse strikes a cloud of a noble gas emerging from a tiny nozzle. The electrons in the gas atoms absorb the laser energy and subsequently re-emit it in the form of an attosecond pulse. Photo: Thorsten Naeser

Figure legend, Fig. 2: Generation of attosecond laser pulses at the Max Planck Institute for Quantum Optics: A femtosecond laser pulse strikes a cloud of a noble gas emerging from a tiny nozzle. The electrons in the gas atoms absorb the laser energy and subsequently re-emit it in the form of an attosecond pulse. Photo: Thorsten Naeser