We demonstrate that higher-order acoustic phonon oscillations of self-assembled Au nanoparticles can be excited using higher frequency bandwidth picosecond acoustic pulses generated by superdiffusive hot electrons. These modes require directional excitations such as a longitudinal strain pulse, being inaccessible in a direct optical excitation scheme. They are detected using the periodic shift of the surface plasmon resonance and are coherently controlled by a sequence of delayed acoustic pulses. Acoustic mode calculations show that the high-frequency mode corresponds to two higher-order spheroidal modes.

中文翻译：

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由超扩散热电子产生的一系列超短应变脉冲控制的金纳米颗粒中的高阶声子声子振荡

我们证明自组装金纳米粒子的高阶声子声子振荡可以使用由超扩散热电子产生的更高频率带宽的皮秒声脉冲来激发。这些模式需要定向激励，例如纵向应变脉冲，这是直接光学激励方案无法实现的。使用表面等离振子共振的周期性位移来检测它们，并通过一系列延迟的声脉冲进行相干控制。声学模式计算表明，高频模式对应于两个高阶球面模式。