Spin-dependent polariton scattering and all-optical control of transverse patterns in semiconductor microcavities

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This project is focussed on the formation and optical control of patterns in coherently driven microcavity polariton systems. Quantum-well based semiconductor microcavites are spatially homogeneous in the quantum-well plane. Plane-wave pump excitation in normal incidence does not spoil the translational and rotational symmetry in the plane. Nevertheless, for pump excitation spectrally above the lower polariton branch, the system can spontaneously break its symmetry and show a spatially non-homogeneous nonlinear optical response: above a certain pump threshold intensity, stimulated off-axis scattering of pump-induced polaritons overcomes the intrinsic losses in the off-axis modes such that off-axis signals spontaneously build up and are emitted from the cavity under a finite angle. It is the purpose of this project to study in detail the resulting self-organization in the driven nonlinear system and related pattern formation. Important insights were already obtained in the first funding period of this project. In the project continuation we will particularly focus on spin-dependent aspects of the pattern formation. Aim is to achieve a deep understanding of the underlying microscopic physics and explore how spinor effects can be used to control the patterns, e.g., for all-optical switching. Our theoretical work will be done closely together with our experimental collaborators.