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Flexible plasmonic spin-Hall effect and its applications
1  Shanghai University


Optical spin-Hall effect (OSHE) is a spin-dependent transport phenomenon of light. Although being discovered decades ago, OSHEs are usually extremely weak and in uncontrollable manner owning to the inability to fully control the spin-orbit coupling [1]. Recently, the development of metasurfaces open a new way for control the spin-dependent splitting of light beam by using a single sheet metamaterials [2-3]. However, these previous works on OSHE only demonstrated simple and symmetric splitting of the two spins [1-3], far from the capability to generate independent OSHEs, which can then work coherently together for more flexible and tunable functionalities. Here, we present a plasmonic metasurface consisting of an array of nano-slots with tailor-made orientation profiles to generate independent surface plasmon polariton (SPP) patterns on the metasurface with the two incident spins [4]. For example a “cross” pattern for one spin and a “triangle” pattern for another as incidence. With such flexible control of OSHEs, we also demonstrate that it is possible to make the two spins work coherently together by controlling the relative phase between the two polarizations, which allows us to play motion pictures, for example, to write a letter “b” with a series of picture frames. Our work may stimulate more applications in near-field optics, such as optical integrated circuits, tip-free near-field scanning optical microscopy, and plasmonic tweezers to trap and move micron size particles.