Two-photon spin-polarization spectroscopy in silicon-doped GaAs.
We generate spin-polarized electrons in bulk GaAs using circularly polarized two-photon pumping with excess photon energy (DeltaE) and detect them by probing the spin-dependent transmission of the sample. The spin polarization of conduction band electrons is measured and is found to be strongly dependent on DeltaE. The initial polarization, pumped with DeltaE=100 meV, at liquid helium temperature is estimated to be approximately 49.5%, which is very close to the theoretical value (50%) permitted by the optical selection rules governing transitions from heavy-hole and light-hole states to conduction band states in a bulk sample. However, the polarization pumped with larger DeltaE decreases rapidly because of the exciting carriers from the split-off band.
Nanoscale Science and Technology Centre, School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111, Australia. m.miah@griffith.edu.au
M Idrish
MI
Miah
D017785:Photons; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry*; D013057:Spectrum Analysis; D013696:Temperature
D012825:Silicon