Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 59: Graphene: Applications, luminescence and spin relaxation (HL with O/TT)

HL 59.6: Talk

Wednesday, March 18, 2015, 18:00–18:15, ER 270

Coherent and Incoherent Photoluminescene from Photo-excited Graphene — •Torben Winzer¹, Richard Ciesielski², Matthias Handloser², Alberto Comin², Achim Hartschuh², and Ermin Malic¹ — ¹Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Germany — ²Department Chemie, Ludwig Maximilians Universität München, Germany

Based on a microscopic theory and experimental measurements we investigate the ultrafast photoluminescence arsing from photo-excited graphene. Our calculations, performed within the density matrix formalism, allow for energy- and time-resolved insights into the radiative processes where two distinct microscopic mechanisms are distinguished: Beside the incoherent photoluminescence, which is driven by recombination of excited carriers, we find a coherent contribution induced by the microscopic polarization [1]. The incoherent spectrum mainly depends on the excitation strength. In contrast, the coherent photoluminescence spectrally shifts with the excitation energy, which is demonstrated for the first time and confirmed by our measurements. [1] T. Winzer, R. Ciesielski, M. Handloser et al., arXiv:1411.0531v1 (2014)