Controlling the spin-selective absorption with two-dimensional chiral plasmonic gratings.

Spin-selective absorption in a two-dimensional (2D) chiral plasmonic grating is observed by excitation of chiral-dependent plasmonic cavity resonance. For the proposed structures, the incident right-handed circularly polarized light is absorbed with nearly 100% efficiency, whereas the incident left-handed circularly polarized light is reflected with same handedness. Moreover, we show that the location of spin-selective absorption can be controlled flexibly by tuning the plasmonic cavity dimension. The intensity of spin-selective absorption can be enhanced as well as suppressed based on Fabry-Perot interference phase relation. Such 2D chiral plasmonic gratings could find many potential applications in novel photon-spin selective devices, such as circularly polarized light detectors/emitters, chiral sensors, chiral cavities, and spin lasers. (C) 2019 Optical Society of America