Ultrafast Optical Spectroscopy of Large-Momentum Excitons in GaAs

G. Göger; M. Betz; A. Leitenstorfer; M. Bichler; W. Wegscheider; G. Abstreiter

doi:10.1103/PhysRevLett.84.5812

Ultrafast Optical Spectroscopy of Large-Momentum Excitons in GaAs

G. Göger, M. Betz, A. Leitenstorfer, M. Bichler, W. Wegscheider, and G. Abstreiter

Phys. Rev. Lett. 84, 5812 – Published 19 June 2000

Abstract

Highly energetic excitons with wave vectors much larger than that of an absorbed photon are excited in thin GaAs films. We observe propagation beats between three polariton modes up to 300 meV above the absorption edge employing femtosecond transmission spectroscopy. The dispersion relations of the coherent excitations are measured. Ultrafast exciton damping via scattering with nonequilibrium carriers and with phonons is investigated. The dynamics is found to deviate strongly from the relaxation of free carriers. Theoretical simulations are in quantitative agreement with the data.

Received 22 February 2000

DOI:https://doi.org/10.1103/PhysRevLett.84.5812

Authors & Affiliations

G. Göger¹, M. Betz¹, A. Leitenstorfer¹, M. Bichler², W. Wegscheider³, and G. Abstreiter²

¹Physik-Department E 11, Technische Universität München, D-85748 Garching, Germany
²Walter-Schottky-Institut, Technische Universität München, D-85748 Garching, Germany
³Institut für Angewandte und Experimentelle Physik, Universität Regensburg, D-93040 Regensburg, Germany