• 摘要: 微纳结构的非互易光学传输特性在微纳光学、通信和材料科学等领域中具有重要应用。本文研究一种基于Au@Ag核壳纳米颗粒超晶格薄膜的非互易反射特性。通过界面自组装方法制备超晶格薄膜,采用硝酸刻蚀和二次生长策略,实现对Au@Ag超晶格薄膜正向/反向非对称反射特性的调控。实验利用硝酸刻蚀工艺去除银壳层,通过调节刻蚀时间,薄膜的正向和反向反射率差异得到了显著增强,其中3层结构的反射率差值达到19.7%。随后,在刻蚀后的薄膜表面通过二次生长法制备了星状金纳米团簇结构,进一步破坏薄膜的对称性,二次生长后的薄膜在前向和后向反射率差值提高至75.3%。该自组装薄膜能够降低器件制备成本,可用于非互易功能化微纳光子器件的设计。

       

      Abstract: Non-reciprocal optical transmission properties of micro-nanostructures have important applications in the fields of micro-nano optics, communications, and materials science. In this paper, the nonreciprocal reflective properties of a superlattice film based on Au@Ag core-shell nanoparticles are investigated. The superlattice film was prepared by the interfacial self-assembly method, and the nitric acid etching and secondary growth strategies were used to realize the modulation of the forward/reverse asymmetric reflection properties of the Au@Ag superlattice film. The nitric acid etching process was utilized to remove the silver shell layer in the experiments, and the difference between the forward and reverse reflectivity of the films was significantly enhanced by adjusting the etching time, in which the reflectivity difference of the 3-layer structure reached 19.7%. Subsequently, star-shaped gold nanocluster structures were prepared on the surface of the etched film by the secondary growth method to further disrupt the symmetry of the film, and the difference between the forward and backward reflectivity of the second-grown film was enhanced to 75.3%. The self-assembled films can reduce the cost of device preparation and can be used for the design of non-reciprocal functionalized micro- and nanophotonic devices.