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arXiv · 2204.03604

Unidirectional ultracompact DNA-templated optical antennas

Fangjia Zhu·Maria Sanz-Paz·Antonio Fernandez-Dominguez·Xiaolu Zhuo·Luis M. Liz-Marzan·Fernando D. Stefani·Mauricio Pilo-Pais·Guillermo P. Acuna
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Abstract

Optical nanoantennas are structures designed to manipulate light-matter interactions at the nanoscale by interfacing propagating light with localized optical fields. In recent years, a plethora of devices have been realized that are able to efficiently tailor the absorption and/or emission rates of fluorophores. By contrast, modifying the spatial characteristics of their radiation fields remains a challenge. Up to date, the designs providing directionality to fluorescence emission have required compound, complex geometries with overall dimensions comparable to the operating wavelength. Here, we present the fabrication and characterization of DNA-templated ultracompact optical antennas, with sub-wavelength sizes and capable of directing single-molecule fluorescence into predefined directions. Using the DNA origami methodology, two gold nanorods are assembled side-to-side with a separation gap of 5 nm. We show that a single fluorescent molecule placed at the tip of one of the nanorods drives the dimer antenna in anti-phase, leading to unidirectional emission.

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Fangjia Zhu, Maria Sanz-Paz, Antonio Fernandez-Dominguez, Xiaolu Zhuo, Luis M. Liz-Marzan, Fernando D. Stefani, Mauricio Pilo-Pais, Guillermo P. Acuna. 2022-04-07. Unidirectional ultracompact DNA-templated optical antennas. https://doi.org/10.1021/acs.nanolett.2c02424

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