Enhanced spin–orbit coupling in an epsilon-near-zero material

Light can carry both spin and orbital angular momentum. While it is known that a nonparaxial circularly polarized beam couples the momentum to momentum, this phenomenon does not hold upon collimation of field. With rising interest in epsilon-near-zero photonics, integral ingredients field are beam-shaping capabilities such regime. In work, experimentally shown permanent conversion spin-to-orbital arises naturally from an incident on isotropic interface due asymmetry Fresnel coefficients. More significantly, efficiency be substantially enhanced presence film unique properties exhibited It further scales with nonparaxiality Our study showcases intriguing phenomena resulting combination concepts as old coefficients modern materials films.