Self-Assembly of Plasmonic Nanoantenna-Waveguide Structures for Subdiffractional Chiral Sensing

Rothe M, Zhao Y, Mueller J, Kewes G, Koch CT, Lu Y, Benson O (2021)

Publication Type: Journal article

Publication year: 2021

Journal

ACS nano American Chemical Society

Book Volume: 15

Pages Range: 351-361

Journal Issue: 1

DOI: 10.1021/acsnano.0c05240

Abstract

Spin-momentum locking is a peculiar effect in the near-field of guided optical or plasmonic modes. It can be utilized to map the spinning or handedness of electromagnetic fields onto the propagation direction. This motivates a method to probe the circular dichroism of an illuminated chiral object. In this work, we demonstrate local, subdiffraction limited chiral coupling of light and propagating surface plasmon polaritons in a self-assembled system of a gold nanoantenna and a silver nanowire. A thin silica shell around the nanowire provides precise distance control and also serves as a host for fluorescent molecules, which indicate the direction of plasmon propagation. We characterize our nanoantenna-nanowire systems comprehensively through correlated electron microscopy, energy-dispersive X-ray spectroscopy, dark-field, and fluorescence imaging. Three-dimensional numerical simulations support the experimental findings. Besides our measurement of far-field polarization, we estimate sensing capabilities and derive not only a sensitivity of 1 mdeg for the ellipticity of the light field, but also find 103 deg cm2/dmol for the circular dichroism of an analyte locally introduced in the hot spot of the antenna-wire system. Thorough modeling of a prototypical design predicts on-chip sensing of chiral analytes. This introduces our system as an ultracompact sensor for chiral response far below the diffraction limit.

Involved external institutions

Humboldt-Universität zu Berlin DE Germany (DE) Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) DE Germany (DE)

How to cite

APA:

Rothe, M., Zhao, Y., Mueller, J., Kewes, G., Koch, C.T., Lu, Y., & Benson, O. (2021). Self-Assembly of Plasmonic Nanoantenna-Waveguide Structures for Subdiffractional Chiral Sensing. ACS nano, 15(1), 351-361. https://doi.org/10.1021/acsnano.0c05240

MLA:

Rothe, Martin, et al. "Self-Assembly of Plasmonic Nanoantenna-Waveguide Structures for Subdiffractional Chiral Sensing." ACS nano 15.1 (2021): 351-361.

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