After the initial development in gas phase, attosecond (1 as = 10-18 s) spectroscopy techniques are now read for application to condensed targets where fundamental physics questions still remain unanswered: Which are the mechanisms that dominate the coherent response during light-matter interaction? Which is and what determines the speed limit at which we can coherently manipulate charges in a solid? Are physical laws developed from macroscopic models still valid on attosecond and nanometric scales? In order to answer these important questions, we need a probe capable to interview the sample with sub-femtosecond time resolution. Attosecond extreme-ultraviolet pulses represent the perfect tool to reach this goal.
 

Attosecond dynamics in bulk solids

In this thesis work, attosecond extreme-ultraviolet (XUV) pulses will be employed in combination with few femtosecond infrared (IR) pulses to perform transient absorption or transient reflectivity measurements in bulk solid crystals. The main goal of the work is to study effects like carrier injection, dynamical screening, exciton formation, electron localization and correlation on sub-femtosecond time scale with unprecedented time resolution.

Attosecond dynamics in advanced 2D materials       

2D materials are a class of advanced materials which research in the fields of condensed matter physics, materials science, chemistry, and nanotechnology has grown exponentially in the recent years. Due to the quantum confinement in one direction and reduced coulomb screening, these materials exhibit unique features like strong light-mater interaction and enhanced many-body and excitonic effects. As such, they constitute the ideal target to study the early dynamics of these phenomena with attosecond transient absorption or reflectivity techniques. This thesis work aims to the development of novel investigation techniques in order to investigate exotic physical properties in 2D materials with attosecond resolution.
 
This thesis work will be performed in the ERC-granted AuDACE laboratory: 
http://www.attosecond.fisi.polimi.it/