Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 29: 2D Materials: Graphene
HL 29.4: Talk
Thursday, September 8, 2022, 10:15–10:30, H36
All-optical modulation of third harmonic generation in graphene — •Omid Ghaebi1, Sebastian Klimmer1, Habib Rostami2, and Giancarlo Soavi1 — 1Institute of Solid-State Physics, Friedrich Schiller University, Jena, Germany — 2Nordita, KTH Royal Institute of Technology and Stockholm University, Sweden
Graphene is a unique platform for non-linear optics thanks to its linear band dispersion that allows gate tunable resonant light-matter interactions [1]. While the gate tunability of THG have been investigated in recent years [1], less is known about the possibility to realize all-optical nonlinear modulators, which could provide higher modulation speed (THz) compared to electrical modulators (GHz) [2]. In this work, we show all-optical TH modulation in graphene at different values of the Fermi level and with a modulation depth up to 85%. First, we demonstrate that it is possible to actively control the THG recombination dynamics by tuning the graphene Fermi level. This is due to phase-space filling and quenching of the scattering between hot electrons and optical phonons [3]. In addition, we reveal the interplay between TH modulation due to increase in the electronic temperature and due to Pauli blocking at different values of the Fermi level. This work offers new insights for the understanding of TH all-optical modulation and thus for the realization of ultrafast frequency converters and nonlinear modulators. [1] Soavi, G. et al. Nature Nanotechnology 13, 583-588 (2018). [2] Cheng, Y. et al. Nano Letters 20, 8053-8058 (2020). [3] Pogna, E. A. et al. ACS Nano 15, 11285-11295 (2021).