Ultrafast switching of tunable infrared plasmons in indium tin oxide nanorod arrays with large absolute amplitude
Ultrafast switching of tunable infrared plasmons in indium tin oxide nanorod arrays with large absolute amplitude
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DOI：
10.1038/nphoton.2016.14
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发表时间：
2016-04-01
期刊：
影响因子：
35
通讯作者：
Chang, Robert P. H.
中科院分区：
文献类型：
--
作者：
Guo, Peijun;Schaller, Richard D.;Chang, Robert P. H.
等离子体激元的全光控制可以使光开关具有高速度、小尺寸和高开/关比。在这里，我们展示了超快等离子体激元调制在近红外（NIR）到中红外（MIR）范围内的带内泵浦的铟锡氧化物纳米棒阵列（ITO-NRA）。我们观察到红移的局域表面等离子体共振所产生的ITO，这是由导带非抛物性的等离子体频率的变化。我们概括的等离子体频率的非抛物线带，定量模型的能量密度依赖的等离子体频移，并表明，不同的贵金属，在ITO中的较低的电子密度，使电子分布的显着变化，产生显着的等离子体频率调制和随之而来的大的瞬态漂白和诱导的反射，这可以通过调整ITO-NRA几何光谱调谐。低的电子热容解释了亚皮秒动力学比贵金属快得多。我们的工作展示了一个新的计划，以控制红外等离子体的光开关，电信和传感。
All-optical control of plasmons can enable optical switches with high speeds, small footprints and high on/off ratios. Here we demonstrate ultrafast plasmon modulation in the near-infrared (NIR) to mid-infrared (MIR) range by intraband pumping of indium tin oxide nanorod arrays (ITO-NRAs). We observe redshifts of localized surface plasmon resonances arising from a change of the plasma frequency of ITO, which is governed by the conduction band non-parabolicity. We generalize the plasma frequency for non-parabolic bands, quantitatively model the fluence-dependent plasma frequency shifts, and show that different from noble metals, the lower electron density in ITO enables a remarkable change of electron distributions, yielding a significant plasma frequency modulation and concomitant large transient bleaches and induced absorptions, which can be tuned spectrally by tailoring the ITO-NRA geometry. The low electron heat capacity explains the sub-picosecond kinetics that is much faster than noble metals. Our work demonstrates a new scheme to control infrared plasmons for optical switching, telecommunications and sensing.