Optical nonreciprocity in multilayer nanoisland systems of [Ag–Al₂O₃] _N

Abstract

We study the effect of optical nonreciprocity in [Ag--Al2<\sub>O<sub>3<\sub>]<sub>N<\sub> multilayer structures. The percolation threshold for Ag films was found to be d* ≈ 2 nm. An anomalously large optical nonreciprocity effect was found in the structures with Ag island layers. This effect appeared as a change in the reflected light polarization (Δω) when the sample was rotated around its axis from the initial position by 180°. The effect magnitude reached Δωmax<sub> ≈ 7°. We suggest that a possible mechanism for the optical nonreciprocity effect in these structures can be related to the excitation of localized plasmons in Ag islands. We show that Δω essentially depends on the interlayer and intralayer interaction between Ag layers in multilayer structures and is suppressed in the case of strong intralayer and interlayer interaction of plasma oscillations.