Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 61: Frontiers of Electronic Structure Theory: Organics and Materials (jointly with O, HL)
TT 61.5: Vortrag
Mittwoch, 18. März 2015, 11:45–12:00, MA 004
Ab initio Simulation of Optical Limiting: The Case of Metal-Free Phthalocyanine — •Caterina Cocchi1,2, Deborah Prezzi2, Alice Ruini2,3, Elisa Molinari2,3, and Carlo Andrea Rozzi2 — 1Physics Department and IRIS Adlershof, Humboldt-Universität zu Berlin, Germany — 2Centro S3, CNR Istituto-Nanoscienze, Modena, Italy — 3Dipartimento di Scienze Fisiche, Informatiche, Matematiche, University of Modena and Reggio Emilia, Italy
Optical limiting (OL) is a nonlinear process that is relevant for an entire class of devices related to the protection of light-sensitive elements, including the human eye, from intense light sources. While extensively studied experimentally, an accurate theoretical investigation of this phenomenon is still missing. In the framework of time-dependent density-functional theory, we present a fully ab initio, non-perturbative description of OL properties of a metal-free phthalocyanine, a prototypical macrocyclic organic compound. By applying a broadband electric field of increasing intensity, we confirm that reverse saturable absorption is the leading mechanism for OL phenomena in this class of systems, and reveal that a number of dipole-forbidden excitations are populated by excited-state absorption at more intense external fields. The excellent agreement with the available experimental data supports our approach as an effective and powerful tool to describe and predict OL [1]. [1] C. Cocchi et al., Phys. Rev. Lett. 112, 198303 (2014).