Wang Yong, Liu Xuejun, Whitmore Desiré, Xing Wendong, Potma Eric O
Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, USA.
Opt Express. 2011 Jul 4;19(14):13454-63. doi: 10.1364/OE.19.013454.
We demonstrate dual-color nonlinear excitation of quantum dots positioned onto a gold film at distances up to 40 μm away from a micrometer sized focused laser spot. We attribute the observed remote nonlinear signal to the excitation of two independent surface plasmon polariton (SPP) modes excited at the laser spot in the gold film, which subsequently propagate in a collinear fashion to a distant site and provide the surface field required for nonlinear excitation of the target. This scheme decouples the illuminating photon flux from surface plasmon mediated nonlinear excitation of the target, which provides more control of unwanted heating effects at the target site and represents an attractive approach for surface-mediated femtosecond nonlinear examinations of molecules.
我们展示了量子点的双色非线性激发，这些量子点位于距微米级聚焦激光光斑最远40μm的金膜上。我们将观察到的远程非线性信号归因于在金膜中的激光光斑处激发的两种独立表面等离激元极化激元（SPP）模式，它们随后以共线方式传播到远处，并提供目标非线性激发所需的表面场。该方案将照明光子通量与目标的表面等离激元介导的非线性激发解耦，这能更好地控制目标位置处的不必要加热效应，并且是一种用于分子表面介导飞秒非线性检测的有吸引力的方法。
