Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku 615-8510, Kyoto, Japan.
Nano Lett. 2011 Mar 9;11(3):1374-8. doi: 10.1021/nl200030h. Epub 2011 Feb 22.
We experimentally demonstrate the capability of tailoring lasing resonance properties by manipulating the coupling between surface plasmons and photons in random lasing media composed of metallic-dielectric core-shell nanoparticles and organic dyes. It is revealed that core-shell nanoparticle-based systems exhibit optical feedback features distinctive from those containing pure metallic nanoparticles, provided that the scattering strength is weak enough. The pump threshold increases with an increment in the shell thickness, which can provide a direct proof that the local field enhancement plays a central role in the emergence of coherent feedback. The anomalous behavior in both threshold and optical feedback is discussed in terms of the modification of fluorescent properties of fluorophores close to metallic surface.
我们通过操纵由金属-介质核壳纳米粒子和有机染料组成的随机激光介质中的表面等离激元与光子之间的耦合，实验证明了激光共振特性的可调节性。结果表明，只要散射强度足够弱，基于核壳纳米粒子的系统就会表现出与仅包含纯金属纳米粒子的系统不同的光学反馈特性。泵浦阈值随壳层厚度的增加而增加，这可以直接证明局域场增强在相干反馈的出现中起着核心作用。根据靠近金属表面的荧光团荧光性质的变化，讨论了阈值和光学反馈的异常行为。
