SKM 2021 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 15: Focus Session: Tailored Nonlinear Photonics

HL 15.5: Hauptvortrag

Donnerstag, 30. September 2021, 12:15–12:45, H4

Supercontinuum second-harmonic generation spectroscopy of 2D semiconductors — •Steffen Michaelis de Vasconcellos — Institute of Physics and Center for Nanotechnology, University of Münster, Germany

The emergence of 2D materials has opened up a wealth of new research topics for a wide variety of applications. The intensive research efforts on 2D materials were initially ignited by the groundbreaking work on graphene. Since then, the family of 2D crystals and their heterostructures has been expanding rapidly. The research has been focusing not only on their unique electrical properties, but also on their fascinating optical, mechanical, thermal, and chemical properties. Several of the materials are particularly suited for establishing nonlinear light-matter interactions. The strong optical nonlinearity, broadband and tunable optical absorption, and ultrafast response of these materials have been successfully employed in all-optical modulators, saturable absorbers used in passive mode locking and Q-switching, wavelength converters, and optical limiters.

A powerful tool to gain insight into nanoscale materials is the prototypical nonlinear process second-harmonic generation (SHG) due to its dependence on crystal symmetry and electronic structures. We developed a new method to perform ultra-broadband SHG spectroscopy, which provides access to the frequency-dependent nonlinear susceptibility χ⁽²⁾ of atomically thin materials and allows for the identification of the prominent excitonic resonances.