Enhanced Photonic Spin Hall Effect with a Bimetallic Film Surface Plasmon Resonance

Abstract

The surface plasmon resonance (SPR) with the bimetallic film can achieve minimum reflectivity and higher evanescent field enhancement than the SPR configuration with the single gold film, which makes it to be a much better option for enhancing the photonic Spin Hall Effect (SHE). It is found that the thicknesses of silver and gold films have a major impact on the photonic SHE, and the maximal transverse shift of horizontal polarization state can reach to 5.34 μm near the SPR resonant angle by optimizing the thicknesses of silver and gold films in the bimetallic film. Our results are far greater than the previously reported transverse shifts in the conventional SPR structure. This novel phenomenon is attributed to the higher evanescent field enhancement and the larger refractive index variation gradient of silver/gold bimetallic film. These findings provide us an effective method to manipulate the photonic SHE and therefore establish a strong foundation for developing photonic devices based on photonic SHE.