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4/2: Christos Flytzanis, Laboratoire Pierre Aigrain, Ecole Normale Superieure (France)
ECE Seminar: Photoinduced Magnetic Ordering and Spin Photogalvanic Effect In a Semimagnetic Semiconductor Quantum Microcavity
2:00PM, 8 Saint Mary's Street, room 339

Abstract
We use the connection between spin-photogalvanic effects in cascade and the photo-induced polarization state rotation to follow the optically driven spin dynamics in semimagnetic semiconductors with a time resolved photoinduced Faraday rotation technique.

Using such a picosecond pump and probe time resolved technique we evidence a single pump pulse photo-induced magnetic ordering in a Mn-doped semiconductor quantum microcavity operating in the strong coupling regime at room temperature. This nanosecond duration Mn-magnetization mediated through photo-generated holes and enhanced through the confinement is distinct from the short lived optical spin orientation of carriers also evidenced by our technique.

The photogenerated flux amounts to 1kG for beam fluences of few tens µJ/cm2. Large magneto-optic Kerr effect rotations are also measured.