Dresden 2003 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 53: Heterostrukturen

HL 53.4: Vortrag

Freitag, 28. März 2003, 12:30–12:45, BEY/118

Collective absorption of Coulomb-coupled quantum oscillators - the extreme nonlinear regime — •Stefan Bärthlein and Claus Metzner — Institut für Technische Physik I, FAU Erlangen-Nürnberg

We theoretically investigate the nonlinear optical response of inhomogeneous arrays of two-level systems, which are interacting via long range Coulomb fields. The absorption spectra for coherent laser light are calculated directly in the time-domain by solving the coupled density matrix equations for finite oscillator clusters.

In the interesting regime of high light intensity and strong interactions, we find unexpected extreme changes of the spectral shape, due to the interplay of collective behaviour and saturation effects. We compare our results to a rotating wave approximation and to a semi- analytical mean-field approximation.

In addition, we design a semiconductor nanostructure for intersubband absorption experiments which would allow a direct test of our theoretical results.