Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
J Chem Phys. 2017 Feb 28;146(8):084704. doi: 10.1063/1.4977079.
We investigate the dynamics of the photon echo exhibited by exciton-plasmon systems under strong coupling conditions. Using a self-consistent model based on coupled Maxwell-Bloch equations, we investigate the femtosecond time dynamics of ensembles of interacting molecules optically coupled to surface plasmon supporting materials. It is shown that observed photon echoes under a two pulse pump-probe sequence are highly dependent on various material parameters such as molecular concentration and periodicity. Simulations of photon echoes in exciton-plasmon materials reveal a unique signature of the strong exciton-plasmon coupling, namely, a double-peak structure in spectra of recorded echo signals. This phenomenon is shown to be related to hybrid states (upper and lower polaritons) in exciton-plasmon systems under strong coupling conditions. It is also demonstrated that the double-peak echo is highly sensitive to mild deviations of the coupling from resonant conditions making it a great tool for ultrafast probes.
我们研究了在强耦合条件下激子-等离子体系统表现出的光子回波的动力学。我们使用基于耦合麦克斯韦-布洛赫方程的自洽模型，研究了光学耦合到支持表面等离子体的材料的相互作用分子的飞秒时间动力学。结果表明，在双脉冲泵浦-探测序列下观察到的光子回波高度依赖于各种材料参数，如分子浓度和周期性。在激子-等离子体材料中的光子回波的模拟揭示了强激子-等离子体耦合的独特特征，即在记录的回波信号的光谱中出现双峰结构。这种现象被证明与强耦合条件下的激子-等离子体系统中的混合态（上和下极化激元）有关。还表明，双峰回波对耦合偏离共振条件的微小偏差非常敏感，使其成为超快探针的绝佳工具。
