Anna Galler

Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

A glimpse into the optical response of solids: from color pigments to laser-driven 2D
materials

Optical phenomena in solids are fascinating and of great importance for technological
applications. In this talk, I will first present a novel approach to compute the optical response and
color of non-toxic, inorganic pigment materials from first principles. I will show that the brilliant
colors of my target materials, certain transition-metal oxides and rare-earth semiconductors, are
strongly influenced by the presence of transition-metal and rare-earth electronic states, whose
theoretical treatment requires elaborate many-body techniques.
The second part of the seminar will be focused on nonlinear optical phenomena. I will investigate
the response of monolayer hexagonal boron nitride, a prototypical 2D semiconductor, to intense
ultrafast laser pulses. I will show that the conduction band charge occupation induced by an
elliptically-polarized laser can be understood in a multi-photon resonant picture, but remarkably,
only if using the Floquet light-dressed states instead of the undressed matter states.
[1] Ransmayr, Tomczak and Galler, PRM 6, 105003 (2022)
[2] Galler, Rubio and Neufeld, arXiv:2303.15055 (2023)