A unique feature of exciton-polaritons, inherited from their mixed light-matter origin, is the strongly spin-dependent polariton-polariton interaction, which has been predicted to result in the formation of spin rings in real space [Shelykh et al., Phys. Rev. Lett. 100, 116401 (2008)]. Here we experimentally demonstrate the spin bi-stability of exciton-polaritons in an InGaAs-based semiconductor microcavity under resonant optical pumping. We observe the formation of spin rings whose size can be finely controlled in a spatial scale down to the micrometer range, much smaller than the spot size. We additionally evaluate the sign and magnitude of the antiparallel polariton spin interaction constant.
@article{arxiv.1007.3575,
title = {Spin rings in bi-stable planar semiconductor microcavities},
author = {C. Adrados and A. Amo and T. C. H. Liew and R. Hivet and R. Houdre and E. Giacobino and A. V. Kavokin and A. Bramati},
journal= {arXiv preprint arXiv:1007.3575},
year = {2010}
}