# Séminaire d'Institut

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Mardi 5 Novembre 2024 à **14h00**.

## Ab-initio simulation of laser-matter interaction from microscopic to macroscopic

**Kazuhiro Yabana**

(Université de Tsukuba, Japan)

**Amphi Dirac**

Invité(e) par

**Rajarshi Sinha Roy**

présentera en 1 heure :

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In the field of optical science, two computational methods have been developed and used to describe the interaction of light and matter. One is a numerical electromagnetics, which solves the macroscopic Maxwell equations where properties of matters are taken into account through dielectric functions. The other is first-principles quantum mechanical methods for calculating dielectric functions. Thus the macroscopic electromagnetism (EM) and quantum mechanics (QM) has been separated using constitutive relations. In current frontiers of optical science, however, numerous developments have occurred in those areas where EM and QM cannot be separated. For example, interaction of strong laser pulse with matter causes extremely nonlinear phenomena such as high harmonic generations. In attosecond science, electronic motion in matters can be directly explored in real time where computations of light- matter interaction in atomic scale play an indispensable role. In the interaction of nanostructures and pulsed light, nonlocal responses caused by quantum effects in nanostructures are often significant. We have been developing computational methods in which EM and QM are combined: First-principles time-dependent density functional theory is used to describe electronic motion in matter, and is coupled with Maxwell equations to describe light propagation as well. In my seminar, I will explain the methodology and present several applications of the new method.

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