Department of Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
Department of Physics and Astronomy, Rice University , 77005 Houston, United States.
Nano Lett. 2016 Aug 10;16(8):5183-90. doi: 10.1021/acs.nanolett.6b02154. Epub 2016 Jul 28.
Three-dimensional chiral plasmonic nanostructures have been shown to be able to dramatically boost photon-spin selective light-matter interactions, potentially leading to novel photonics, molecular spectroscopy, and light-harvesting applications based on circularly polarized light. Here, we show that chiral split-ring gold nanoresonators interfaced to a wide band gap semiconductor exhibit a contrast in hot-electron transfer rate between left-handed and right-handed visible light that essentially mimics the far-field circular dichroism of the structures. We trace down the origin of this effect to the differential excitation of the thinnest part of the split-ring structures using dichroic-sensitive cathodoluminescence imaging with nanometer spatial resolution. The results highlight the intricate interplay between the near-field and far-field chiral response of a nanostructure and establishes a clear link to the emerging field of hot carrier plasmonics with numerous potential applications in photocatalysis and solar light harvesting.
三维手性等离子体纳米结构已被证明能够显著增强光子-自旋选择性光物质相互作用，从而可能为基于圆偏振光的新型光子学、分子光谱学和光捕获应用提供基础。在这里，我们展示了与宽带隙半导体接口的手性分裂环金纳米谐振器在左旋和右旋可见光之间表现出的热电子转移率的对比度，该对比度实质上模拟了结构的远场圆二色性。我们通过具有纳米空间分辨率的二向色敏感的阴极发光成像，追溯了这种效应的起源，这归因于分裂环结构的最薄部分的差分激发。研究结果突出了纳米结构的近场和远场手性响应之间的复杂相互作用，并与新兴的热载流子等离子体学领域建立了明确的联系，该领域在光催化和太阳能收集等领域具有众多潜在应用。
