Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 23: Spin controlled transport II
HL 23.2: Talk
Tuesday, March 27, 2007, 14:15–14:30, H14
Fast polarization switching in room temperature Spin-VCSEL — •Stephan Hövel1, Nils Gerhardt1, Martin Hofmann1, Fang-Yuh Lo2, Dirk Reuter2, and Andreas Wieck2 — 1Optoelectronic Devices and Materials, Ruhr-University Bochum, IC2/133, Universitätsstr. 150, 44780 Bochum, Germany — 2Applied solid state physics, Ruhr-University Bochum, NB03/58, Universitätsstr. 150, 44780 Bochum, Germany
Spin controlled vertical-cavity surface-emitting lasers (VCSELs) are very promising devices for future spintronic applications, because of their ability to amplify electron spin information. We could show amplified polarization degrees by all optical test experiments in an InGaAs/GaAs-VCSEL at room temperature [1, 2]. Here we present time-resolved polarization measurements of the optically pumped VCSEL showing a fast switching behaviour on a ps timescale between opposite circular polarization states in a single laser pulse. The complex polarization dynamics do not depend on carrier density, spin polarization or excitation wavelength alone, but are additionally influenced by inhomogenities and strain of the sample structure. Understanding the polarization dynamics is therefore a key issue on the way to electrically pumped Spin-VCSELs. Taking the time-resolved polarization measurements into account, design considerations for a future electrically pumped Spin-VCSEL for both room temperature as well as highly modulated polarization switching will be discussed.
[1] S. Hövel et al., Electronics Letters 41, 251 [2] N. Gerhardt et al., Electronics Letters 42, 88