Nonlinear Chiro-Optical Amplification by Plasmonic Nanolens Arrays Formed via Directed Assembly of Gold Nanoparticles
Nonlinear Chiro-Optical Amplification by Plasmonic Nanolens Arrays Formed via Directed Assembly of Gold Nanoparticles
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DOI：
10.1021/nl504613q
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发表时间：
2015-03-01
期刊：
影响因子：
10.8
通讯作者：
Vaia, Richard A.
中科院分区：
文献类型：
--
作者：
Biswas, Sushmita;Liu, Xiaoying;Vaia, Richard A.
金属纳米粒子组件由于其等离子体模式产生的新颖的线性和非线性光学特性而成为纳米光子应用的有前途的材料。然而，提供精确的纳米和宏观结构以及与设计和模型预测相称的性能的可扩展制造方法一直受到限制。在这里，我们展示了控制和有效的纳米聚焦入射线偏振光和圆偏振光的基频和次谐波频率，使用减少对称金纳米粒子二聚体形成的胶体纳米粒子的表面定向组装。这些C-ov异源二聚体的大有序阵列（bbb100）（半径R-1/R-2 = 150 nm/50 nm = 3；间隙距离l = 1 +/- 0.5 nm）表现出二次谐波产生和结构相关的光活性，单个异源二聚体的圆二色比在阵列上变化小于20%，显示出大规模的精度和均匀性。这些非线性光学性质是由粒子间等离子体耦合介导的。此外，在包括柔性聚合物在内的各种基材上证明了制造的多功能性。数值模拟指导了结构设计以及验证实验结果，从而证实了通过合理设计和制造纳米结构来优化紧凑型传感器、光调制器和可调谐光源的二次谐波产率和诱导手光学响应的能力。
Metal nanoparticle assemblies are promising materials for nanophotonic applications due to novel linear and nonlinear optical properties arising from their plasmon modes. However, scalable fabrication approaches that provide both precision nano- and macroarchitectures, and performance commensurate with design and model predictions, have been limiting. Herein, we demonstrate controlled and efficient nanofocusing of the fundamental and second harmonic frequencies of incident linearly and circularly polarized light using reduced symmetry gold nanoparticle dimers formed by surface-directed assembly of colloidal nanoparticles. Large ordered arrays (>100) of these C-ov heterodimers (ratio of radii R-1/R-2 = 150 nm/50 nm = 3; gap distance l = 1 +/- 0.5 nm) exhibit second harmonic generation and structure-dependent chiro-optic activity with the circular dichroism ratio of individual heterodimers varying less than 20% across the array, demonstrating precision and uniformity at a large scale. These nonlinear optical properties were mediated by interparticle plasmon coupling. Additionally, the versatility of the fabrication is demonstrated on a variety of substrates including flexible polymers. Numerical simulations guide architecture design as well as validating the experimental results, thus confirming the ability to optimize second harmonic yield and induce chiro-optical responses for compact sensors, optical modulators, and tunable light sources by rational design and fabrication of the nanostructures.