Dynamics of amplification in a nanoplasmonic metamaterial
Dynamics of amplification in a nanoplasmonic metamaterial
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DOI：
10.1007/s00339-012-6784-y
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发表时间：
2012-02
期刊：
影响因子：
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通讯作者：
S. Wuestner;A. Pusch;J. Hamm;K. Tsakmakidis;O. Hess
中科院分区：
文献类型：
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作者：
S. Wuestner;A. Pusch;J. Hamm;K. Tsakmakidis;O. Hess
等离子体超材料形成了一种令人兴奋的新型工程介质，有望实现一系列重要的应用，如亚波长聚焦，隐身和减缓/停止光。最近已经表明，由于金属在光频率的自然吸收而引起的内部损耗可以通过增益来补偿。在这里，我们采用麦克斯韦-布洛赫方法，使我们能够研究相干等离子体增益相互作用，非线性饱和，场增强和辐射阻尼的动力学。利用数值泵浦-探测实验研究了含染料分子的双鱼网超材料在低Qfishnet腔中的反转和等离子体激元模的形成。我们发现，损失补偿发生在负折射率制度，由于损失补偿和相关的锐化的谐振，超材料的折射率的真实的部分变得更负相比，被动的情况下。此外，我们调查的行为的超材料以上的激光阈值，我们确定发生的远场激光脉冲和增益耗尽。我们的研究结果提供了深入了解的内部过程，影响宏观性能的有源超材料。这可以指导放大和激光等离子体纳米结构的发展。
Plasmonic metamaterials form an exciting new class of engineered media that promise a range of important applications, such as subwavelength focusing, cloaking and slowing/stopping of light. Recently it has been shown that the internal losses due to the natural absorption of metals at optical frequencies can be compensated by gain. Here, we employ a Maxwell–Bloch methodology which allows us to study the dynamics of the coherent plasmon-gain interaction, nonlinear saturation, field enhancement and radiative damping. Using numerical pump-probe experiments on a double-fishnet metamaterial with dye-molecule inclusions we investigate the buildup of the inversion and the formation of the plasmonic modes in the low-Qfishnet cavity. We find that loss compensation occurs in the negative-refractive-index regime and that, due to the loss compensation and the associated sharpening of the resonance, the real part of the refractive index of the metamaterial becomes more negative compared to the passive case. Furthermore, we investigate the behavior of the metamaterial above the lasing threshold, and we identify the occurrence of a far-field lasing burst and gain depletion. Our results provide deep insight into the internal processes that affect the macroscopic properties of active metamaterials. This could guide the development of amplifying and lasing plasmonic nanostructures.