Ultrafast circular polarization oscillations in spin-polarized vertical-cavity surface-emitting laser devices

Gerhardt, N. C. and Li, M. and Jaehme, H. and Soldat, H. and Hofmann, M. R. and Ackemann, T. (2010) Ultrafast circular polarization oscillations in spin-polarized vertical-cavity surface-emitting laser devices. In: Physics and Simulation of Optoelectronic Devices XVIII. Proc. SPIE, 7597 . UNSPECIFIED, 75970Q.

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    Abstract

    Spin-polarized lasers offer new encouraging possibilities for future devices. We investigate the polarization dynamics of electrically pumped vertical-cavity surface-emitting lasers after additional spin injection at room temperature. We find that the circular polarization degree exhibits faster dynamics than the emitted light. Moreover the experimental results demonstrate a strongly damped ultrafast circular polarization oscillation due to spin injection with an oscillation frequency of approximately 11GHz depending on the birefringence in the VCSEL device. We compare our experimental results with theoretical calculations based on rate-equations. This allows us to predict undamped long persisting ultrafast polarization oscillations, which reveal the potential of spin-VCSELs for ultrafast modulation applications.