Final Report Summary - POLAPHEN (Polarization Phenomena in Quantum Microcavities) The investigation of light-matter interactions nanoscale objects attracts the growing interest of researchers. This interest is largely motivated by the possibility of reaching the strong light-matter coupling regime, where the elementary excitations – polaritons – have a hybrid, half-light half-matter nature. The unusual properties of the polaritons make them a unique laboratory for study of fundamental quantum effects such as high temperature Bose Einstein condensation, superfluidity, entanglement etc. The important property of the polaritonic systems is their polarization (spin) properties. The interplay between bosonic stimulated scattering of cavity polaritons and their spin precession under effective magnetic fields of various origin makes polarization dynamics in quantum microcavities extremely rich and interesting from fundamental point of view. Moreover, the possibility to manipulate spin of polaritons opens a way to experimental realization of optoelectronics devices of new generation, i.e. spinoptronic devices. With respect to optics, spin-optronics has the advantage of being able to use well controlled carrier interactions occurring in nanostructures. With respect to ‘spintronics’, it has the advantage of strongly reducing the dramatic impact of carrier spin relaxation or decoherence, which has severely limited the achievement or the functionality of any working semiconductor-based spintronic devices. Our research will be aimed at theoretical study of the coherent polarization (spin) phenomena in quantum microcavities with embedded quantum wells and dots in order to formulate practical recommendations for design of various spinoptronic devices: all-optical locical gates, optical circuits, polarization filters and sources of entangled photon pairs.In order to achieve this goal we created the distributed consortium (network) of partner institutions, located in EU and associated countries (Iceland, France, UK) and in Eligible Third Countries (Mexico, Russia) related with others by virtue of already existing collaborative links. In course of the project we suppose to amplify and order these collaborations under central common idea of studying and optimization of mechanisms of polarization manipulation and control in polaritonic systems with a final goal of practical realization of spinoptronic devices. Series of bilateral visits, training workshops and meetings are previewed for this purpose.