> Attosecond pulses: Flashes of light that last only a few billionths of a billionth of a
second. In one attosecond, light covers a distance of 0.3 nanometers (one nanometer is
one millionth of a millimeter). This corresponds to the diameter of a water molecule.
> Femtosecond pulses: Flashes of light that last one millionth of a billionth of a second –
about one thousand times longer than attopulses.
> Attosecond pulses: Flashes of light that last only a few billionths of a billionth of a second. In one attosecond, light covers a distance of 0.3 nanometers (one nanometer is one millionth of a millimeter). This corresponds to the diameter of a water molecule.
> Femtosecond pulses: Flashes of light that last one millionth of a billionth of a second – about one thousand times longer than attopulses.
https://www.mpg.de/9298413/F002_focus_024-031.pdf