局域表面等离激元诱导的三次谐波增强效应

Enhanced third harmonic generation by localized surface plasmon excitation

本文研究了二维金三角形纳米颗粒阵列的三次谐波非线性光学效应.金三角纳米颗粒阵列是基于微球刻印技术制成.采用反射式光学系统,观察到该纳米结构在光谱分辨的飞秒激光照射下产生明显的三次谐波.研究表明,当激光抽运频率接近金纳米颗粒的局域表面等离激元共振位置时,三次谐波信号得到增强;三次谐波辐射方向满足动量匹配条件.

We experimentally achieved optical third harmonic generation （THG） from two-dimensional periodically arrayed gold-island films. The gold-island films were fabricated using micro-spherical lithography. By using a reflection-type optical system, these arrays can produce significant THG with the help of a spectrum-resolved femto-second laser. At the localized surface plasmon （LSP） excitation wavelength of the fundamental wave, THG is greatly enhanced due to the strong light localization effect. The radiation direction of THG satisfies the momentum matching condition.