Category Archives: lumen

Two-photon absorption in two-dimensional crystals

In this work we combine tight-binding calculations of the two-photon transition probability with sophisticated ab-initio real-time Bethe-Salpeter simulations of the two-photon resonance third-order susceptibility. This combination is a unique feature of this work: on the one hand the tight-binding calculations allow us to identify the symmetry properties of the excitons, on the other hand the… Read More

Invisible excitons in hexagonal Boron Nitride

New talk for the conference “2D layered materials for opto-electronics: a theoretical/computational perspective” in Rome. In this work we study excitations in hexagonal Boron Nitride that are invisible in linear optical response. We show that these dark states can be measured with other spectroscopic techniques and they play an important roles in the luminescence response… Read More

Spin-orbit coupling, polarised light and real-time BSE in Lumen

A new version of the Lumen code is available online. It includes spin-orbit coupling, the possibility to use polarised light and the real-time Bethe-Salpeter equation (RT-BSE). Notice that the RT-BSE is limited to small systems or a small number of G-vectors in the screened-exchange due to its computational time. New tutorials on spin-orbit coupling and… Read More