Xstase

Xstase project is dedicated to the study of the exchanges of angular momenta of light with matter in linear and highly nonlinear regimes. It will provide a full panorama of both Orbital Angular Momenta and Spin Angular Momenta conversions from the IR to the XUV through High Harmonic Generation (HHG); generalizing the use of these fundamental properties of light beams to the femtosecond XUV domain. Xtase will establish, both experimentally and theoretically, the rules of orbital angular momentum conservation through HHG. Experimentally, it will use dedicated setups specifically developed for the project, which will continuously bridge the gap between the low orders of non linearities, already documented in the visible domain, i.e. the multiphoton regime, all the way up to high orders of non linearities, i.e. the non perturbative regime provided by the HHG process. It will provide a framework for further developments of original XUV sources carrying OAM’s, opening the road for future applications in quantum information, imaging of thin surfaces or new kind of spectroscopies. The technological developments required are based on attosecond technologies developed over the past ten years and will in turn feed this domain. In particular, wavefront diagnosis technologies, may it be monitoring its general shape or its coherence will progress significantly through Xstase. Xstase will also develop the fast shaping of the Spin Angular Momentum of attosecond light beams, through a series of dedicated techniques based on ultra-stable interferometers. In particular, it will advance the design of sources adapted to probing chiral specific interactions in the XUV domain, through the use of MultiPhoton Ionization (MPI), PhotoElectron Circular Dichroism (PECD) and X-Natural Circular Dichroism (XNCD). It will make world’s first dynamical observations of these two latter phenomena, setting the stage for new spectroscopic studies of chiral samples. The outcomes are expected to have far reaching applications, linked to the ubiquity of chiral molecules in bio-medical and chemical applications. Indeed, very little is known about the evolution of chirality through elementary processes such as dissociation, excitation, or electronic relaxation at the targeted femtosecond and attosecond timescales. Xstase will address this question directly in a series of test-cases. The potential is extremely high for developing new spectroscopic techniques, perfectly suited to monitor chirality. As a side benefit, it will advance attosecond science through the mastering of polarization properties of XUV pulses. Xstase will finally set the stage for combined studies of SAM and OAM couplings in matter, which is currently a subject of intense theoretical debate. It thus has altogether very promising outcomes for physical chemistry, fundamental physics and attosecond science. It federates a team of theoreticians and experimentalists having very complementary knowledge and knowhow about the building blocks of the project and will be developed in a very dynamical international and national environment. Indeed, this new line of research will develop in the context of the “Attolab” facility, which will be available mid-2015, and has the potential to aggregate a large community, originating from the gas-phase and solid state communities, currently using the quasi continuous synchrotron radiation.