Ultrafast polarization modulation induced by the “virtual excitation” of spin-polarized excitons in quantum wells: Application to all-optical switching

The operation of an all-optical coherent polarization switch that makes use of spin-polarized virtual excitons in unstrained quantum wells is thoroughly investigated experimentally over a wide range of excitation intensities. The device is shown to exhibit a 415 fs switching time and a contrast rati...

Full description

Saved in:
Bibliographic Details
Published in:Journal of applied physics 2004-04, Vol.95 (8), p.3907-3915
Main Authors: Gansen, Eric J., Smirl, Arthur L.
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The operation of an all-optical coherent polarization switch that makes use of spin-polarized virtual excitons in unstrained quantum wells is thoroughly investigated experimentally over a wide range of excitation intensities. The device is shown to exhibit a 415 fs switching time and a contrast ratio of >300:1 at ∼100 K in a thin (40 well) sample. The switching mechanisms are discussed in terms of the circular optical selection rules and the virtual excitation is studied by performing differential measurements for various input polarizations. The polarization state changes induced by the spin-polarized virtual population are measured and their contributions to the switch signal separated using a combination of time-averaged, time-resolved, and spectrally resolved ellipsometric techniques.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.1666977