Active plasmonic nanostructures with tunable resonances promise to enable smart materials with multiple functionalities, on-chip spectral-based imaging and low-power optoelectronic devices. A variety of tunable materials have been integrated with plasmonic structures, however, the tuning range in the visible regime has been limited to less than the line width of the resonance resulting in small on/off ratios. Here we demonstrate dynamic tuning of plasmon resonances up to 71 nm through multiple cycles by incorporating photochromic molecules into plasmonic nanopatch antennas. Exposure to ultraviolet (UV) light switches the molecules into a photoactive state enabling dynamic control with on/off ratios up to 9.2 dB and a tuning figure of merit up to 1.43, defined as the ratio between the spectral shift and the initial line width of the plasmonic resonance. Moreover, the physical mechanisms underlying the large spectral shifts are elucidated by studying over 40 individual nanoantennas with fundamental resonances from 550 to 720 nm revealing good agreement with finite-element simulations.

中文翻译：

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光致变色分子耦合到等离激元纳米天线的单线宽度有源调谐超过了。

具有可调谐共振的有源等离子体纳米结构有望实现具有多种功能的智能材料，基于光谱的片上成像以及低功耗光电器件。各种可调材料已与等离激元结构集成在一起，但是，可见光范围内的调谐范围已被限制为小于共振的线宽，从而导致较小的开/关比。在这里，我们通过将光致变色分子掺入等离子体纳米贴片天线中，展示了通过多个循环可动态调谐高达71 nm的等离子体激元共振。暴露在紫外线（UV）下会将分子切换为光敏状态，从而能够以高达9.2 dB的开/关比和高达1.43的品质因数进行动态控制，定义为频谱偏移与等离子体共振的初始线宽之间的比率。此外，通过研究40多个具有550至720 nm基本共振的单个纳米天线，阐明了发生大光谱位移的物理机制，从而揭示了与有限元模拟的良好一致性。