Thierry Ruchon

Fonction

Research Program Overview

My research topic is focused on attosecond physics. In brief, we develop new generation and analysis schemes to synthetize attosecond light pulses, i.e. light pulses whose duration are in the 10 ^-18 s range. These pulses are necessarily in the XUV region of the spectrum, where most of the optical elements no longer work (even air absorbs in this region). Moreover, they cover an ultra broad spectrum, typically several times the total width of the visible spectrum. This makes their synthesis and characterization challenging, and a current hot research subject.
In our lab, we focus on the upconversion of intense visible femtosecond lasers in gases through the so-called High Harmonic Generation (HHG) process. Basic information on attosecond pulse generation is available in this lecture. In particular, we pay a lot of attention to the measurement of the phase properties of the emitted light, especially to the spectral phase. This is achieved through quantum interferometry of electronic wave packets together with optical interferometry in the XUV. We also investigate the generation of attosecond pulses carrying either or both Spin and orbital angular momenta.
These studies have two types of uses. First, one gains information on the gas used for the generation. It is therefore an Extreme Non Linear Spectroscopy. Second, they may be used to perform time resolved XUV spectroscopy with attosecond resolution.