Polariton spin jets through optical control

We demonstrate spin-polarized jets in extended systems of ballistic exciton-polariton condensates in semiconductor microcavities using optical nonresonant excitation geometries. The structure of the spin jets is determined by the spatially patterned degree of circular polarization of the nonresonant excitation laser. The presence of the laser excitation, strong particle interactions, and spin relaxation leads to a tunable spin-dependent potential landscape for polaritons, with the appearance of intricate polarization patterns due to coherent matter-wave interference. Our work realizes polarization-structured coherent light sources in the absence of gauge fields.