How to focus an attosecond pulse

Attosecond experiments involving focusing of attosecond light pulses can suffer from a spread of the attosecond radiation both in space and time due to optical aberrations. We present a detailed numerical study of the distortions induced in the most common focusing geometries that make use of parabolic, spherical, toroidal and ellipsoidal mirrors. We deduce the consequences on the pulse duration and possible issues that could arise in applications of attosecond pulses. This should serve as a guideline for setting up attosecond focusing optics.