等离子体增强的超高灵敏度二次谐波纳米尺。

Plasmon-Enhanced Second-Harmonic Generation Nanorulers with Ultrahigh Sensitivities.

机构信息

Department of Physics, Xiamen University , Xiamen 361005, China.

State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.

出版信息

Nano Lett. 2015 Oct 14;15(10):6716-21. doi: 10.1021/acs.nanolett.5b02569. Epub 2015 Sep 17.

DOI:10.1021/acs.nanolett.5b02569

PMID:26372425

Abstract

Attainment of spatial resolutions far below diffraction limits by means of optical methods constitutes a challenging task. Here, we design nonlinear nanorulers that are capable of accomplishing approximately 1 nm resolutions by utilizing the mechanism of plasmon-enhanced second-harmonic generation (PESHG). Through introducing Au@SiO2 (core@shell) shell-isolated nanoparticles, we strive to maneuver electric-field-related gap modes such that a reliable relationship between PESHG responses and gap sizes, represented by "PESHG nanoruler equation", can be obtained. Additionally validated by both experiments and simulations, we have transferred "hot spots" to the film-nanoparticle-gap region, ensuring that retrieved PESHG emissions nearly exclusively originate from this region and are significantly amplified. The PESHG nanoruler can be potentially developed as an ultrasensitive optical method for measuring nanoscale distances with higher spectral accuracies and signal-to-noise ratios.

摘要

通过光学方法实现远远低于衍射极限的空间分辨率是一项具有挑战性的任务。在这里，我们设计了非线性纳米标尺，通过利用等离子体增强二次谐波产生（PESHG）的机制，能够实现约 1nm 的分辨率。通过引入 Au@SiO2（核@壳）壳隔离纳米粒子，我们努力操纵电场相关的间隙模式，以便获得 PESHG 响应与间隙大小之间的可靠关系，用“PESHG 纳米标尺方程”表示。通过实验和模拟验证，我们已经将“热点”转移到了薄膜-纳米粒子-间隙区域，确保了所提取的 PESHG 发射几乎完全来自该区域，并得到了显著增强。PESHG 纳米标尺有望成为一种超灵敏的光学方法，用于以更高的光谱精度和信噪比测量纳米级距离。