Facile Design of a Plasmonic Nanolaser
Facile Design of a Plasmonic Nanolaser
复制标题
等离激元纳米激光器的简易设计
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
C. Kryschi
中科院分区：
文献类型：
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作者：
Hans;C. Kryschi
Spaser由等离子体贵金属纳米结构组成，当结合或表面耦合的两级发射体构成纳米级增益介质时，其充当纳米腔。合适的二能级发射器例如是激光染料。光泵浦可以在增益介质中的两能级发射体和纳米腔中维持的表面等离子体之间提供有效的激发能量转移。表面等离子体激元模式与增益介质的强共振耦合可以建立最终驱动spaser作用的固有反馈放大机制。在这方面的贡献，我们表明，spaser发射可以产生放大纵向表面等离子体模式的金纳米棒通过光泵浦表面附着的共振耦合激光染料。因此，我们合成了金纳米棒，其纵向表面等离子体共振峰被调节在680和700 nm之间。增益介质是通过静电吸附的激光染料酞菁四磺酸盐通过带正电荷的十六烷基三甲基溴化铵（CTAB）双层的金纳米棒表面。酞菁四磺酸盐在700 nm处显示荧光。荧光猝灭实验明确地给出了共振激发能量转移的指示。荧光强度比IF 0 /IF遵循Stern-Volmer关系，Stern-Volmer系数确定为KSV = 1.22 × 106 M−1。在飞秒瞬态吸收光谱中观察到spaser发射，在716 nm附近为超快衰减的窄发射峰。
A spaser consists of a plasmonic noble-metal nanostructure that acts as nanocavity, when incorporated or surface-coupled two-level emitters constitute the nanoscale gain medium. Suited two-level emitters are, for instance, laser dyes. Optical pumping may provide efficient excitation energy transfer between the two-level emitters in the gain medium and the surface plasmons sustained in the nanocavity. Strong resonant coupling of the surface plasmon modes to the gain medium may establish an inherent feedback amplification mechanism which finally drives the spaser action. In this contribution, we demonstrate that spaser emission can be generated by amplifying longitudinal surface plasmon modes in gold nanorods by optically pumping surface-attached resonantly-coupled laser dyes. Therefore, we synthesized gold nanorods whose longitudinal surface plasmon resonance peak was adjusted between 680 and 700 nm. The gain medium was realized by electrostatically attaching the laser dye phthalocyanine tetrasulfonate via the positively-charged CTAB (cetyltrimethylammonium bromide) bilayer to the gold-nanorod surface. Phthalocyanine tetrasulfonate exhibits fluorescence at 700 nm. Fluorescence quenching experiments unambiguously gave indication of resonant excitation energy transfer. The fluorescence intensity ratio I F 0 / I F follows the Stern–Volmer relationship, and the Stern–Volmer coefficient was determined as KSV = 1.22 × 106 M−1. The spaser emission was observed in fs transient absorption spectra as an ultrafast decaying narrow emission peak around 716 nm.