Domain, Specialties : Laser
Keywords: Non linear optics, Physical chemistry, Ultrafast lasers
Research Unit : LIDYL / ATTO
Summary
Electronic motion in molecules is now accessible thanks to attosecond (10-18 s) spectroscopic tools. The characterization of these pulses of light and their generation were the focus of the 2023 Nobel Prize in Physics, and have since been applied mainly to the study of isolated systems. We are now looking to study more complex systems such as molecules in liquid phase, where many-body dynamics are still unknown on these extreme time scales. To take this step, we are developing an ultrafast laser experiment based on ytterbium architectures beyond the current state of the art. Now that the foundations of this system are operational, we are looking to generate isolated attosecond pulses of up to 200 eV, compatible with our liquid phase sampling system. Such a system will be unique, and its development is at the heart of this Master’s internship, in collaboration with a PhD student and a post-doc already working on the project.
Full description
The ERC-starting grant SATTOC project aims to study the electronic movements of molecules in a solvated medium on the attosecond time scale. In this complex environment, electronic interactions are key to understand and even control the reactivity of compounds. We are currently developing experimental laser tools based on high-order harmonic generation and, more generally, non-linear optical effects to achieve the sensitivity and temporal resolution required for these measurements. We are therefore aiming to combine isolated attosecond pulses with our state-of-the-art sampling system capable of creating sheets of water just 200 nm thick under vacuum, necessary for the transmission of our x-rays.
To do this, we need state-of-the-art laser tools. We installed a new 80 W ytterbium laser system (40 kHz, 2 mJ and 350 fs initially) which we post-compressed to 8 fs pulse duration using a multipass cell and a hollow-core fiber. Now that we have this source at our disposal, we aim to use it to generate and characterize our attosecond pulses ranging from 50 to 200 eV, thus reaching soft x-rays. This unique source will enable us to study a whole range of yet unexplored molecular dynamics, from solute-solvent charge transfer following inner-shell ionization, to the detection of chiral molecules using UV-x-ray sum frequency generation protocols.
We are currently working on setting up the vacuum equipment needed for the experiment, which will be ready for the start of this M2 internship. The internship will focus on characterizing this state-of-the-art laser source, as well as initiating attosecond measurements on liquids. The latter will be at the heart of a thesis starting in October 2025, towards which the M2 trainee will be encouraged.
Location
CEA – Saclay, 91 Essonne, France
Internship conditions
- Internship duration: 5 months
- Level of study: Bac+5
- Training: Master 2
- Continuation in PhD thesis: Yes
- Application deadline: 3 mars 2025
Experimental skills
Language : English
Useful methods and technics:
- high order hamonics generation
- optical fiber (solitonic and other),
- charaterization of UV ultrashort pulses
- Vacuum technologies
Computer languages and software: python
Links
Supervisor
Hugo Marroux
Phone: 0647233965
Email :