Spin Current Generation by a Surface Plasmon Polariton

Surface plasmon polariton (SPP) is an electromagnetic wave which is tightly localised beyond the diffraction limit at metallic surfaces. Recently, it is theoretically proposed that the angular momentum conversion between the SPP and electrons. In this work, we have successfully measured SPP induced spin currents, which proves the fact that the angular momenta are interconverted. Such conversion from light to a spin current can be used as a coupler in a next generation spintronic computing with optical data transfer or storage.