Unusual and Tunable One-Photon Nonlinearity in Gold-Dye Plexcitonic Fano Systems
Unusual and Tunable One-Photon Nonlinearity in Gold-Dye Plexcitonic Fano Systems
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金染料 Plexcitonic Fano 系统中异常且可调的单光子非线性
DOI：
10.1021/acs.nanolett.5b00413
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发表时间：
2015-04-01
期刊：
影响因子：
10.8
通讯作者：
Zhang, Zhenyu
中科院分区：
文献类型：
--
作者：
Nan, Fan;Zhang, Ya-Fang;Zhang, Zhenyu
金属纳米结构的等离子体激元激发与分子物种的激子激发之间的耦合的最新研究揭示了被称为plexcitonics的各种各样的涌现现象。在这里，我们使用相结合的实验和理论方法来证明新的和有趣的方面，在超快的非线性响应的强耦合的混合Fano系统组成的金纳米棒装饰近红外染料分子。我们发现，严重抑制的线性吸收周围的法诺浸显着增强的单向能量转移从等离子体激子，并进一步允许单光子非线性大幅和可逆调谐。这些惊人的观察解释在一个微观模型强调两个竞争过程：饱和等离子体吸收和削弱破坏性Fano干扰漂白激子吸收。这里揭示的异常强的单光子非线性提供了一个很有前途的策略，在制造纳米等离子体器件具有显着的非线性和良好的品质因数。
Recent studies of the coupling between the plasmonic excitations of metallic nanostructures with the excitonic excitations of molecular species have revealed a rich variety of emergent phenomena known as plexcitonics. Here, we use a combined experimental and theoretical approach to demonstrate new and intriguing aspects in the ultrafast nonlinear responses of strongly coupled hybrid Fano systems consisting of gold nanorods decorated with near-infrared dye molecules. We show that the severely suppressed linear absorption around the Fano dip significantly enhances the unidirectional energy transfer from the plasmons to the excitons and further allows one-photon nonlinearity to be drastically and reversibly tuned. These striking observations are interpreted within a microscopic model stressing on two competing processes: saturated plasmonic absorption and weakened destructive Fano interference from the bleached excitonic absorption. The unusually strong one-photon nonlinearity revealed here provides a promising strategy in fabricating nanoplasmonic devices with both pronounced nonlinearities and good figures of merit.