Multiphoton ionization processes, driven by a superposition of XUV high harmonics and an IR pulse, are of interest from the point of view of the Physics involved and for applications to the femtosecond and attosecond metrology. The RABITT method [1] for instance, which relies on a two-photon two color total ionization signal has been investigated in details. Studies of the angular properties of such transitions are at their commencement. Beyond single ionization, the release of two electrons by absorption on one or several photons can also be explored with this tool. Such studies fill the gap between the huge corpus of data resulting from decades of synchrotron experiments and the more recent interest for strong field double ionization. They also pave the road for future studies of single color XUV nonlinear processes.

This talk will discuss two recent experiments carried out at LOA in France and MBI in Berlin. The first one deals with angular distributions of single ionization of helium in a two-color two and three-photon processes [2]. The basic tool for these measurements is a toroidal electron spectrometer with position-sensitive detection. The second with single [3] and double [4] ionization of xenon by IR and XUV pulses using the COLTRIMS method.

Current results will be discussed and future developments will be sketched.

[1] P. Paul et al. Science (2001)

[2] O. Guyetand et al. J. Phys B  At. Mol. Opt. Phys. Letter(2005) in press

[3] M. Boettcher et al. J. Phys. B. At. Mol. Opt. Phys. Letter(2005) in press

[4] M. Boettcher et al. in preparation