Double-Slit and Square-Slit Interferences With Surface Plasmon Polaritons Modulated by Orbital Angular Momentum Beams

We present two kinds of interferences on metallic thin films with orbital angular momentum (OAM) beams, namely, double-slit interference and square-slit interference. When an OAM beam is normally incident upon the metallic thin film with two slits, the fringes on the metallic thin film generated by the interference of two surface-plasmon-polariton waves will twist, and the twist amount depends on the topological charge of the incoming OAM beam. When a square slit is employed, a quasi-square optical lattice will be unveiled, and the arrangement of lattice can be modulated by the OAM beam. The fringes and spots are both at the subwavelength level, which show great potential for superresolution microscopy, OAM detection, and spot-array generation.