Tailoring ultrashort light pulses is a promising way of investigating fundamental questions about ultrafast electronic dynamics in matter, with new technological applications to follow. The current project advances attosecond physics by tackling two major bottlenecks:
(i) How to generate frequency-tunable attosecond XUV pulses carrying spin or orbital angular momentum?
Tunability is crucial for probing resonant signatures in the electronic and magnetization dynamics of matter on the attosecond time scale.
We propose to shape a pair of femtosecond pulses in an original way, then combine them using attosecond delay lines, in order to drive the generation of XUV pulses through the generation of high harmonics.
The XUV spectrum generated will be continuously tunable, with delay control.
These XUV pulses will be used to probe electron dynamics on the attosecond scale, starting with simple targets and continuing with complex two-dimensional materials.
(ii) Magnetization dynamics on the femtosecond scale was discovered 25 years ago, but remains a hotly debated and imperfectly understood subject.
Not only is the theory extremely difficult, but experimental data remain incomplete. Today, it is difficult to probe magnetization in all directions in space at these time scales.
Moreover, optomagnetic signals are not clearly isolated from background noise.
The second novelty of this project lies in the full exploitation of all light’s degrees of freedom to probe the ultrafast magnetization dynamics of d-block elements, which play a central role in the development of optoelectronic devices.
By exploiting XUV light vortices generated by shaped IR pulses, we will be able to build up a comprehensive picture of magnetization dynamics on the femtosecond timescale.
The potential benefits of this project could be extended to demonstrating our ability to control light excitation and probe in 3D the dynamics of non-scalar quantities, which are ubiquitous in condensed matter and the physics of surfaces and interfaces.
Finally, this project brings together the complementary expertise of four accomplished researchers, from India and France, to realistically achieve the ambitious goals mentioned.