偏振响应纳米狭缝阵列制备与光学性质

Preparation and Optical Properties of Polarization-Dependent Nano-Gap Array

提出一种利用微球自组装技术制备具有偏振依赖特性的金属纳米狭缝阵列的方法,该阵列以聚苯乙烯微球薄膜为掩模版,通过倾斜蒸镀银膜获得。对纳米狭缝阵列透射光谱与入射偏振角度的关系进行测量,纳米狭缝阵列具备用于光开关的偏振响应特性。利用时域有限差分法,对该结构的透射光谱和共振波长处的电场强度分布进行仿真计算,并分析结构中存在的表面等离激元模式以及结构参数对透射光谱的影响。通过仿真计算可得该结构的折射率灵敏度可达992 nm/RIU。

A metal nano-gap array with polarization-dependent optical properties prepared by self-assembly technology of microspheres is proposed.The structure is fabricated based on the mask of periodic polystyrene(PS)microsphere film,followed with tilted vacuum evaporation coating of metal film.The relationship between the transmission spectrum of the nano-gap array and the incident polarization angle is measured,and it exhibits polarization-dependent properties that can be used as optical switches.The finite-difference-time-domain(FDTD)method is used to simulate the transmission spectrum of the nano-gap array and the electric field intensity distributions at the resonant wavelengths.Furthermore,the surface plasmon modes and the influence of geometry parameters on transmission spectra are studied.The refractive index sensitivity of this structure reaches as high as 992 nm/RIU.