laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Séminaire Jeunes, 13 Janvier 2016

Ombline Lafont (PHD LPA)
Controler l’effet Hall optique de spin avec la lumière

The spin Hall effect became the paradigm for spintronics by allowing for the generation and separation of electron spins. In this context, the discovery of the optical spin Hall effect (OSHE) opened new perspectives for the generation of long-lived spin currents by optical means. This was shown using spin-polarized polaritons generated by laser excitation in semiconductor microcavities and allows generating polariton spin textures and currents across hundreds of μm. The physical basis of the OSHE is the TE-TM splitting-induced effective magnetic field that causes a pseudo-spin-orbit coupling. Nevertheless, present knowledge shows only limited control over the OSHE, hampering the emergence of new devices that would require the fine and simple control over the spin states in the nonlinear operation regime. Here, we predict and experimentally demonstrate the optical control of the OSHE. We show that the effective magnetic field can be finely tuned using an optical pump beam that tilts the effective magnetic field vector out of the 2D plane in the pseudo-spin space to which it is otherwise confined. This can be viewed as a Faraday effect without need for an external magnetic field, opening new perspectives for instance in the field of quantum information processing.