The advent of table-top-terawatt lasers has opened the pos- sibility of realizing XUV radiation sources based on extre- mely high order harmonic generation. Some unique features of such radiation are: coherence, short pulse duration, small divergence and tunability. Several aspects of the har- monic generation process are still under study in order to determine experimental conditions that maximize the XUV pho- ton flux. The final goal is to obtain XUV radiation intensi- ties above 1012 W/cm2 which will open a new branch of Ato- mic Physics, namely multiphoton processes with XUV radia- tion. To this end, the applicant will focus his work on harmonic generation optimization, on guiding and focusing of XUV radiation and on some specific application in XUV multiphoton processes.