Asymmetric transmission in nanophotonics

Abstract In a reciprocal medium, transmission of electromagnetic (EM) waves is symmetric along opposite directions which restrict design and implementation various systems in optics photonics. Asymmetric (AT) essential for designing isolators circulators photonics, it benefits other applications such as photovoltaic systems, lasers, cloaking, EM shielding. While bulky nonreciprocal devices based on magnetic field biases have been well known, creating AT subwavelength structures more challenging, with thickness that show drawn lot attention over the last decade. Various approaches reported to create metasurfaces featuring transmission, plasmonic dielectric enhance Faraday rotation, nonlinear intensity-dependent refractive indices, implementing spatiotemporal modulation metasurface. On hand, has also by multiple paths changing polarization light or redirecting higher-order diffraction orders. Here, we present review implemented realizing both systems. We discuss main principles limitations achieved approaches.