Abstract
Plasmonic tip nanofocusing has gained much attention owing to its wide application in the field of nanospectroscopy. Here, we present the Au nanosphere (AuNS)-assisted coupling ultrafast surface plasmon polaritons (SPP) background-free tip nanofocusing. The plasmonic tip was prepared by attaching an AuNS on the shaft of an Au conical tip fabricated by electrochemical etching. The AuNS was adopted as an antenna to couple the far-field excitation light to the propagating SPP along the shaft to the tip apex for achieving power compression. Importantly, we experimentally and theoretically demonstrate that such a plasmonic tip can realize background-free ultrafast SPP tip nanofocusing with radially polarized features in a wide spectral range based on the localized SPP resonance effect supported by AuNS. Furthermore, the intensity of the tip nanofocusing light field has strong polarization dependence under linearly polarized light excitation, providing a powerful platform for spatiotemporal light control on the nanoscale. Our technique realizes remote excitation of background-free tip nanofocusing with a structured light feature, and it holds promising potential for tip-enhanced nanospectroscopies, nonlinear nanophotonics, etc.
© 2021 Optical Society of America
Full Article | PDF ArticleMore Like This
Shima Fardad, Justinas Lialys, Laurynas Lialys, and Alessandro Salandrino
Opt. Lett. 46(11) 2581-2584 (2021)
Jing Yang, Chuang Hu, Qiuling Wen, Chenglong Zhao, and Jiasen Zhang
Opt. Lett. 40(6) 978-981 (2015)
Gian Paolo Papari, Zahra Mazaheri, Can Koral, and Antonello Andreone
Opt. Lett. 46(11) 2601-2604 (2021)