Spin-controlled vertical-cavity surface-emitting lasers (VCSELs) have been intensively studied in recent years because of the low threshold feasibility and the nonlinearity above threshold, which make spin-VCSELs very promising for spintronic devices. Here we investigate the circular polarization dynamics of VCSELs on a picosecond time scale after pulsed optical spin injection at room temperature. A hybrid excitation technique combining continuous-wave (cw) unpolarized electrical excitation slightly above threshold and pulsed polarized optical excitation is applied. The experimental results demonstrate ultrafast circular polarization oscillations with a frequency of about 11 GHz. The oscillations last inside the first undulation of the intensity relaxation oscillations. Via theoretical calculations based on a rate equation model we analyze these oscillations as well as the underlying physical mechanisms.
|Title of host publication||Vertical-Cavity Surface-Emitting Lasers XV|
|Editors||J. K. Guenter, Chun Lei|
|Number of pages||8|
|Publication status||Published - 7 Feb 2011|
- polarization oscillations
- laser devices
Ackemann, T., Li, M. Y., Jaehme, H., Soldat, H., Gerhardt, N. C., & Hofmann, M. R. (2011). Spin induced gigahertz polarization oscillations in vertical-cavity surface-emitting laser devices. In J. K. Guenter, & C. Lei (Eds.), Vertical-Cavity Surface-Emitting Lasers XV (Vol. 7952, pp. 79520B). (Proc. SPIE). https://doi.org/10.1117/12.873758