Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 71: Focus Session: Tailored Nonlinear Photonics II
HL 71.5: Talk
Thursday, March 19, 2020, 16:30–16:45, POT 51
Indirect optical transitions induced by a refractive index front — Mahmoud Gaafar1,2, Hagen Renner1, Manfred Eich1,3, and •Alexander Petrov1,4 — 1Institute of Optical and Electronic Materials, Hamburg University of Technology, Hamburg, Germany — 2Department of Physics, Menoufia University, Menoufia, Egypt — 3Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany — 4ITMO University, St. Petersburg, Russia
Refractive index fronts in dispersive waveguides can lead to indirect transition of light where frequency and wavenumber is changed. At the new position on the dispersion relation light might have strong change of the group velocity. Adjusting the front velocity and dispersion relation, reflection, transmission and trapping by the front are possible. We experimentally implement the free carrier front in silicon waveguides by the two photon absorption of the pump pulse and show all three effects. In case of trapping, also known as optical push broom effect, the light is trapped in the front and strongly compressed in time and space. Also transitions to zero group velocity are possible to stop and store optical pulses. We will make an overview of the possible front induced transitions and provide the outlook for the further research.