Experimental Probing of Canonical Electromagnetic Spin Angular Momentum Distribution via Valley-Polarized Photoluminescence

The canonical formulation of the spin angular momentum (SAM) of light has been suggested recently as an extension of the Abraham-Minkowski controversy. However, experimental substantiations of the canonical SAM for localized fields have not been reported yet. We directly probe the locally distributed canonical SAM tailored by a plasmonic nanostructure via the valley-polarized photoluminescence of the multilayer WS2. The spectrum-resolved measurement details the spin-selective Raman scattering and exciton emission beyond the conventional manner of employing circularly polarized paraxial waves.