局域表面等离激元场时空演化的相干控制

Coherent Control of Spatiotemporal Evolution of the Localized Surface Plasmon Field

等离激元具有独特的物理特性,在许多研究领域得到了重要应用。目前,在微观尺度下等离激元与物质作用动力学演化的相干控制,正广受关注。本文分别模拟了入射光为单色连续光、正啁啾脉冲与负啁啾脉冲时,非对称金纳米十字结构的光学响应。发现当采用单色连续光照射时,纳米结构中热点的空间位置具有很好的稳定性,正啁啾脉冲时能够激发产生两种共振模式,并对等离激元场在不同结构位置的时间演化规律进行了分析。当采用负啁啾脉冲时,两种共振模式的激发顺序相反,实现了对等离激元时空演化的有效调控。该研究对于等离激元纳米器件设计和优化具有重要意义。

Surface plasmons have been used in many research fields for the unique physical properties. At present, coherent control of dynamical evolution of surface plasmons and matter on the micro scale is widely concerned. In this paper, the optical response of asymmetric gold cross nanostructure is simulated when the incident light is monochromatic continuous light, positive chirped pulse and negative chirped pulse, respectively. It is found that when the positive chirped pulse is used, two resonance modes can be generated, and the time evolution law of the plasmon field at different positions of the structure is analyzed. To the negative chirped pulse, the excitation sequence of the two resonant modes is opposite, so the plasmon field can be effectively manipulated. This study is of great significance for the design and optimization of plasmonic nano-devices.