Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 46: Ultra-fast phenomena
HL 46.12: Vortrag
Freitag, 5. April 2019, 12:30–12:45, H31
Bringing nonlinear stimulated emission to the infrared: From sapphire and fused silica to perovskites — •Thomas Winkler1, Sean Bourelle1, Thomas Baumert2, and Felix Deschler1 — 1Cavendish Laboratory, University of Cambridge, United Kingdom — 2Institut für Physik und CINSaT, Universität Kassel, Deutschland
While the stimulated emission of light was postulated over more than a hundred years ago and the laser has found its way into every laboratory, its nonlinear counterpart (i.e. two-photon stimulated emission) has only been observed in a handful of experiments so far. Therefore it was very surprising when we recently discovered the nonlinear amplification of an ultraviolet femtosecond laser pulse in a piece of optically excited sapphire (LADIE effect [1]). The effect holds high promises for laser technology, nonlinear microscopy and laser-spectroscopy as it provides e.g. a different set of selection rules. Here, we present extended studies showing the possibility of switching between two nonlinear amplification processes in fused silica, one being related to free carriers, whereas the other is related to the characteristic and self-trapped excitons. Furthermore, we discuss our recent studies to expand the nonlinear stimulated emission from the ultraviolet into the infrared regime. To that extend we utilize novel 2D and 3D perovskite materials, which showed great properties for optoelectronic devices. Having band gaps in visible spectrum and long carrier lifetimes, they are an ideal sample system to probe the two-photon stimulated emission in an ultrafast pump-probe experiment with tunable- and broadband infrared probe pulses. [1]T.Winkler et al. Nature Physics 14, 74-79 (2018)