Enhanced infrared Faraday rotations and transmission in nonreciprocal magneto-optical structure

Abstract

At present, most of all the micro/nano scale structure is reciprocal material, that is, behave as reciprocity. Corresponding to the reciprocal material, the nonreciprocal materials can break the time reversal and detailed balance due to the special nonreciprocal effect, which can lead to nonreciprocal optical devices when magnetism is applied. In this paper, the Faraday rotation effect of an open square hole magnetic plasma structure with periodic corner openings has been studied. The size of the magneto-optical plasmon film is only 600 nm, which is extremely small compared to a hundred-micron magneto-optical garnet film. It is found that the Faraday deflection angle can be adjusted by changing the size of the applied magnetic field without affecting the transmittance. Moreover, the influence of the width of the metal structure and the thickness of the magneto-optical material on the Faraday effect is studied. The maximum Faraday deflection angle can be achieved as 22° and the transmittance is up to 0.63, as the side length of corner openings is set to 100 nm. At the same time, the mechanism of the giant Faraday effect is further explained through the output electric field distribution. It is found that the optical isolation had a high non-reciprocal Faraday rotation and optical transmission enhancement, which will has application in infrared optical isolation.