Category Archives: non linear optics

New talks at the 2017 ETSF conference in Frascati

Here my new two talks at the 2017 ETSF conference in Franscati. The first on Scientific Publishing and the SciPost journal where I will discuss the actual situation of the scientific publishing system and how new green open access journal, like SciPost, could change it. The second talk on the Lumen code, an ab-initio code… Read More

My thesis for the Habilitation à Diriger des Recherches

The first draft of my  thesis for the accreditation to direct research (Habilitation à Diriger des Recherches) is available online. The thesis covers my studies of the non-linear response in solids and nanostructures by means of real-time simulations.  In the thesis I discuss how to couple electrons and external fields by means of Modern Theory… Read More

Density Functional Polarization Theory

We present a new paper on Density Functional Polarization Theory (DFPT). This theory is an extension of Time-Dependent-DFT where the exchange correlation functional depends not only from the density but also from the polarization P. Thanks to this explicit dependence on P it is possible  solve different problems of TD-DFT in periodic systems with a… Read More

Nonlinear response of solids within the GW plus Bethe-Salpeter approximation

My new talk for the GDR-Corr is available online. In this talk I will present our new (probably not so new now) approach to calculate non-linear response in extended systems within the GW plus Bethe-Salpeter equation. I  put different references in the presentation that can be interesting for the reader.

Strong second harmonic generation in SiC, ZnO, GaN two-dimensional hexagonal crystals from first-principles many-body calculations

We published a new paper on the second harmonic generation(SHG) in two-dimensional hexagonal crystals SiC, ZnO and GaN. The SHG is calculated within the so called GW plus Bethe-Salpter formalism, using a real-time implementation proposed by some of us. We found that these system present a large region with a strong SHG before the absorption… Read More

Excitons in second harmonic generation

Together with Myrta Gruning we just submitted a new paper on second harmonic generation(SHG)  in two-dimensional materials, h-BN and MoS2. We calculated the SHG using a real-time approach that we recently developed. We included both local field effects and electron-hole interaction at the level of screened exchange , without any additional approximation. Our approch is… Read More

Nonlinear optics by means of the dynamical Berry-phase

We present an ab-initio real-time based computational approach to nonlinear optical properties in Condensed Matter systems[1]. The equation of motions, and in particular the coupling of the electrons with the external electric field, are derived from the Berry phase formulation of the dynamical polarization.[2] The zero-field Hamiltonian includes crystal local field effects and the renormalization… Read More