一种温控的可调表面等离子体光学器件

A Temperature-Controlled Tunable Plasmonic Dual-Band Absorber

设计加工了一个三层结构的表面等离子体光学吸收器件,表层结构为规则排列的金质椭圆形微粒。入射电磁波与椭圆形金粒作用激发表面等离子体共振时,由于沿长短轴方向谐振频率不同,使得该器件实现了在近红外谱段两个频率处对入射光近100%的吸收。实验样品用电子束曝光技术加工,实验测量与仿真设计结果一致。此外,由于改变器件表面介质的折射率可以有效调谐器件的谐振特性,通过在器件表面覆盖一向列型液晶层并由温度控制液晶层的折射率,实现了一种温控的可调表面等离子光学吸收器件,调节过程简单可靠并且可重复实现,调节范围达22nm。该器件由于其高吸收效率和可调谐特性,可在太阳能电池以及未来光子集成电路等方面得到重要应用。

A plasmonic dual-band absorber based on a three-layer metal-dielectric-metal structure with an gold elliptical nanodisk array arranged on the top layer is designed and fabricated. Nearly 100% absorption is achieved at dual frequencies in near infrared range due to the plasmonic resonances of incident light and gold elliptical nanodisks along major and minor axes. The designed structure is fabricated by electron beam lithography and the measured reflection spectra match well with simulations. Moreover, it shows that the two absorption peaks can be effectively tuned by coating a temperature-controlled nematic liquid crystal layer on top of the device. The tuning process is simple and repeatable with a maximal tuning range of 22 nm. Owing to its high absorption efficiency and tunable property, this plasmonic absorber must have a great potential in the research field such as solar cells and future photonic circuits.