All-optical spectroscopy of matter is a well-established technique to access properties of electrons and quasi-particles in matter. The description of these optical properties is usually done employing ab initio methods such as linear response methods.

Recent advances in experimental techniques have opened up the possibility to develop novel types of spectroscopies based on ultrashort and intense laser pulses, allowing for instance to access non-equilibrium dynamics of condensed-matter systems, coherently control magnetization on ultrafast timescales, or to allow for exploring non-equilibrium phase diagram of correlated materials.

The strong-field electronic dynamics in solids have received a lot of attention, in particular due to the experimental observation of high-harmonic generation in solids. The dynamics associated with strong laser fields requires a non-perturbative description of the electronic dynamics. One possible way of describing this dynamics by ab initio methods is to use real-time time-dependent density functional theory, which will be introduced.

In this talk, I will present some examples of how intense lasers can be used to coherently control materials' properties, in particular correlation and magnetic properties, but also how we can use high-harmonic generation as a spectroscopical tool in condensed matter.