The propagation of both electrons and photons becomes chiral when their momentum and spin are correlated in forms such as spin-momentum locking. For the surface electrons in three-dimensional topological insulators (TIs), their spin is locked to the transport direction. For photons in optical fibers and photonic waveguides, they carry transverse spin angular momentum (SAM) which is also locked to the propagation direction. A direct connection between chiral electrons and chiral photons occurs in Tis with lifted spin degeneracy, which leads to spin-dependent selection rules of optical transition and results in phenomena such as circular photogalvanic effect (CPGE). Here, we demonstrate an optoelectronic device that integrates a TI with a chiral photonic waveguide. Interaction between the photons in the transverse-magnetic (TM) mode of the waveguide, which carries transverse SAM, and the surface electrons in a Bi2Se3 layer generates a directional, spin-polarized photocurrent. Because of
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