Universal Near-Field Spin Properties Of Polarized And Chiral Dipoles

Universal spin-momentum locking of light dictates the direction of transverse spin in the evanescent waves. The coupling between the guided modes of a waveguide and radiating dipoles is also governed by universal spin-momentum locking phenomenon. The spin of the dipole determines the direction of propagation of the coupled wave in the waveguide. We experimentally investigate the radiation behavior of circular and chiral dipoles near a tapered optical fiber. We show that the intrinsic chirality of a chiral dipole plays the role of the spin of a circular dipole in coupling to the modes of an optical fiber.