Visualization of femtosecond plasmon wave-packet by two-photon fluorescence microscopy

利用一台新研制的时间分辨双光子荧光显微镜，以10ps的红外脉冲激光为激发源，以飞秒的时间分辨率显示了表面等离子体波在金属薄膜上的传播运动。对时间分辨电影的分析定量地确定了波包的群速度、相速度、寿命、传播长度和形变。这些实验确定的参数与由多层系统的本征模函数估计的值有很好的一致性。

Motions of propagation of surface plasmon wave packets on metal films are visualized at a femtosecond time resolution by a newly developed time-resolved two-photon fluorescence microscopy using a 10 fs infrared pulse laser as the excitation source. Analyses of the time-resolved moviesquantitatively determine the group velocity, the phase velocity, the lifetime, the propagation length, and the deformation of wave packets. These experimentally determined parameters are in good consistency with the values estimated from an eigenmode function of the multilayer system.