DNA-Templated Ultracompact Optical Antennas for Unidirectional Single-Molecule Emission

ZHU, FANGJIA; SANZ-PAZ, MARÍA; FERNÁNDEZ-DOMÍNGUEZ, ANTONIO I.; ZHUO, XIAOLU; LIZ-MARZÁN, LUIS M.; STEFANI, FERNANDO D.; PILO-PAIS, MAURICIO; ACUNA, GUILLERMO P.

NANO LETTERS (PRINT)

AMER CHEMICAL SOC

Año: 2022 vol. 22 p. 6402 - 6408

1530-6984

Optical antennas are nanostructures designed to manipulate light-matter interactions by interfacing propagating light with localized optical fields. In recent years, numerous devices have been realized to efficiently tailor the absorption and/or emission rates of fluorophores. By contrast, modifying the spatial characteristics of their radiation fields remains challenging. Successful phased array nanoantenna designs have required the organization of several elements over a footprint comparable to the operating wavelength. Here, we report unidirectional emission of a single fluorophore using an ultracompact optical antenna. The design consists of two side-by-side gold nanorods self-assembled via DNA origami, which also controls the positioning of the single-fluorophore. Our results show that when a single fluorescent molecule is positioned at the tip of one nanorod and emits at a frequency capable of driving the antenna in the antiphase mode, unidirectional emission with a forward to backward ratio of up to 9.9 dB can be achieved.