Attosecond science focuses on the study of dynamics in matter at ultimate timescales, using light pulses of attosecond (10-18 s) duration. Our laboratory has pioneered the development and use of these pulses to investigate the ultrafast response of matter. In particular, we operate several platforms dedicated to attosecond spectroscopy of solids.

During this PhD project, we will develop original attosecond experiments aimed at elucidating the dynamics of one of the most important and intriguing degree of freedom of solids: the spins of its electrons. This quantity is responsible for the magnetic properties of materials, with applications ranging from data storage devices to spintronic components. Typically, existing devices use electric currents to convey and manipulate information.
Here, we aim to answer one apparently simple question: can we use a laser field, instead of a current, to control the electronic spins of a solid? While this would have the concrete potential of orders-of-magnitude faster operation, answering this question first requires fascinating fundamental investigations. Indeed, the response of magnetic materials at optical frequencies – below 10 fs – is almost completely unknown to this day. We propose to address this problem by performing experiments that combine spin sensitivity and attosecond resolution for the first time. By carefully shaping attosecond pulses and using state-of-the art detection schemes, we aim to establish a technique called attosecond magnetic dichroism, which will reveal the spin response of materials on the timescale of the electric field of light. We will first focus on simple tridimensional ferromagnetic and antiferromagnetic systems, before evolving towards their bi-dimensional counterparts. Indeed, so-called 2D materials are expected to provide enhanced, or even fundamentally novel light-spin interactions. By understanding how light interacts with electronic spins in 2D, we will provide key elements towards the integration of future low-dimensionality spintronic components.

The student will acquire practical knowledge about experimental ultrafast optics and of time resolved spectroscopy of condensed matter, especially magnetic materials. He/she will become an expert in attosecond physics and technology, as well as acquire valuable skills in complex data acquisition and analysis.