Inverted Leakage Radiation Microscopy for measurement of nonreciprocity induced by a plasmonic metasurface with false chirality
A system has a nonreciprocity when the light propagating through it in opposite directions encounters different optical adventures. This effect lies in the origin of various applications, including signal processing, noise reduction, unidirectional propagation, and sensing. Here, we experimentally demonstrate the detection of nonreciprocity in plasmonic metasurfaces and a method to determine its direction. We use the Inverted Leakage Radiation Microscopy setup to show that the non- reciprocity is linked to a false chirality of the medium. The setup behaves as an equivalent of the classical Sagnac loop providing an interference pattern at the image plane. The non-reciprocity is then detected by examining the topological order of the resulting image. Our system represents a compact and versatile method to detect false chirality in plasmonics and suggests a variety of potential areas of implementation in nanophotonics, chemistry and applied physics.