Metallic nanosphere-assisted coupling ultrafast surface plasmon polaritons background-free tip nanofocusing

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Meng, C., Li, W., Xie, Z., Zhang, L., Xu, L. ORCID: 0000-0001-9071-4311, Gao, F., Zhang, W., Mei, T. and Zhao, J., 2021. Metallic nanosphere-assisted coupling ultrafast surface plasmon polaritons background-free tip nanofocusing. Optics Letters, 46 (22), pp. 5554-5557. ISSN 0146-9592

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Official URL: https://doi.org/10.1364/ol.443079

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.

Item Type:

Journal article

Publication Title:

Optics Letters

Creators:

Meng, C., Li, W., Xie, Z., Zhang, L., Xu, L., Gao, F., Zhang, W., Mei, T. and Zhao, J.

Publisher:

The Optical Society

Date:

15 November 2021

Volume:

Number: