Controlling and measuring the relativistic motion of matter using Ultra-Tense Structured Light
Femtosecond lasers can now deliver intensities such that the light field induces relativistic motion of electron packets.
The ultimate goal of this ultra-high-intensity (UHI) physics is the control of the relativistic motion of matter by light, which requires a thorough understanding of this extreme regime of laser-matter interaction.
Such control promises major scientific and societal applications, providing ultra-compact laser-driven particle gas pedals and attosecond X-ray sources. Until now, progress in the field of UHI physics has been based on the search for the highest laser intensities, by focusing optimally compressed laser pulses right up to their diffraction limit.
In contrast, the aim of the ExCoMet project is to establish a new paradigm, demonstrating the potential of HIF plasma-laser interactions with sophisticated structured laser beams, i.e. high-quality laser beams whose amplitude, phase or polarization are shaped in space-time. Based on this new paradigm, we will show that it is possible to obtain unprecedented experimental information on laser-matter interactions in the UHI.
For example, by using a laser field whose propagation direction rotates on the femtosecond scale, we will temporally resolve the synchrotron emission of relativistic laser-driven electrons in plasmas, thereby obtaining direct information on their dynamics.
We will also show that these structured laser fields can be exploited to introduce new physics into UHI experiments, and can provide advanced degrees of control that will be essential for future light and particle sources based on these interactions. Using Laguerre-Gauss beams, we will study in particular the transfer of orbital angular momentum from UHI lasers to plasmas, and its consequences for the physics and performance of laser-plasma gas pedals. This project aims to make conceptual breakthroughs in UHI physics, at a time when major projects based on this physics are being launched, notably in Europe.