Tailoring ultra-short light pulses is a promising way of studying fundamental questions about the ultrafast electronic dynamics in matter, with foreseen new technological applications.
The current project is advancing attosecond physics by addressing two key bottlenecks: How to generate frequency-tunable attosecond XUV pulses that carry 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 and then combine them using attosecond delay lines, to drive the generation of XUV pulses through High Harmonic Generation.
The XUV generated spectrum will be continuously tunable, with a control by the delay. These XUV pulses will be used to probe electron dynamics at the attosecond scale, starting with simple targets and proceeding to complex two-dimensional materials.
Magnetization dynamics on the femtosecond time scale was discovered 25 years ago, but remains a much debated and imperfectly understood subject. Not only is the theory extremely difficult, but the experimental data remains incomplete.
Today, magnetization is difficult to probe in all directions of space at these time scales. In addition, the optomagnetic signals are not clearly isolated from the background noise.
The second novelty of this project lies in the full exploitation of all the degrees of freedom of light to probe the dynamics of the ultrafast magnetization of d-block elements, which play a central role in the development of opto-electronic devices.
By exploiting XUV light vortices generated with shaped IR pulses, we will be able to build up a complete picture of magnetization dynamics on the femtosecond timescale.