Exciton spin relaxation in InAs/InGaAlAs/InP(001) quantum dashes emitting near 1.55 μm

Exciton spin and related opticalpolarization inself-assembled InAs/In0.53Ga0.23Al0.24As/InP(001) quantum dashes emitting at 1.55  μm are investigated by means of polarization- and time-resolvedphotoluminescence, as well asphotoluminescence excitation spectroscopy, at cryogenic temperature. We investigate the influence of highly non-resonant and quasi-resonant optical spin pumping conditions on spinpolarization and spin memory of the quantum dashground state. We show that a spin pumping scheme, utilizing the longitudinal-optical-phonon-mediated coherent scattering process, can lead to thepolarization degree above 50%. We discuss the role of intrinsic asymmetries in the quantum dash that influence values of the degree ofpolarization and its time evolution.

Source: Applied Physics Letters - November 8, 2016 Category: Physics Authors: M. Syperek, Ł. Dusanowski, M. Gawełczyk, G. Sȩk, A. Somers, J. P. Reithmaier, S. Höfling and J. Misiewicz Source Type: research