Valley-controlled directional coupling to plasmonic nanowire modes

Abstract

The chiral interaction between transverse optical spin and circularly polarized emitters provides a novel way to manipulate spin information at the nanoscale. Here, we demonstrate the valley(spin)-dependent directional emission of transition metal chalcogenides (TMDs) into plasmonic eigenstates of a silver nanowire. Due to the spin-path locking of the plasmonic eigenstates, the emission from the two different valleys of TMDs material will couple to the guided modes propagating in opposite directions. The high valley polarization of TMDs and high density of the transverse optical spin of the plasmonic wire together offer a novel platform for a chiral network even at room temperature without any magnetic fields.