Plasmonic Antennas for Directional Sorting of Fluorescence Emission

Abstract

Spontaneous emission of fluorescent molecules or quantum dots is radiated along all directions when emitters are diluted in a liquid solution, which severely limits the amount of collected light. Besides, the emission direction does not carry any useful information and cannot be used to sort different molecules. To go beyond these limits, optical antennas have been recently introduced as conceptual tools to control the radiation properties for nanoemitters fixed on a substrate. Despite intense recent research, controlling the luminescence directivity remains a challenge for emitters with random positions and orientations, which is a key for several biomolecular screening applications. Here, we present full directional control of the fluorescence emission from molecules in water solution by an optical antenna made of a nanoaperture surrounded by a periodic set of shallow grooves in a gold film. For each emission wavelength, the fluorescence beam can be directed along a specific direction with a given angular width, hereby realizing a micrometer-size dispersive antenna. We demonstrate the fluorescence beaming results from an interference phenomenon and provide physical optics guidelines to control the fluorescence directivity by tuning the groove-nanoaperture distance. This photon-sorting capability provides a new approach for high-sensitivity screening of molecular species in solution.

Dipole Emission to Surface Plasmon-Coupled Enhanced Transmission in Diamond Substrates with Nitrogen Vacancy Center- Near the Surface

“…Most designs, however, are based on the epi-illumination techniques where the incident pump power and the luminescent radiation share the same half-space. See for example the study undertaken by Aouani et al [10,11] on the fluorescence of an ensemble of molecules with randomly oriented dipole moments, trapped inside a plasmonic aperture, when illuminated and collected through the glass substrate. A more deterministic study showed the dependence of the radiation pattern of plasmonic antennas with respect to the distance and the dipolar orientation of a nearby nano-diamond with NV- [7,12].…”

Flexible and Adaptable Light‐Emitting Coatings for Arbitrary Metal Surfaces based on Optical Tamm Mode Coupling

“…[3] These effects result from the strict control over the local density of photon states around the emitter they provide. [4][5][6][7][8] However, the necessary confinement of the active material in a small region close to the metallic resonator entails a restriction on the maximum radiance achievable. An alternative to employing metallic nanostructures is the use of hybrid metal-dielectric systems [9,10] where the electromagnetic field can be tailored in such a way that the emission of light sources can be enhanced while reducing absorption losses.…”

Directional sideward emission from luminescent plasmonic nanostructures

“…In particular, structures supporting localized surface plasmon resonances like single metal nanoparticles [2], more complicated nanoparticle structures [3], nanoapertures in metal films [4,5], and diffractive structures [6,7] have proven efficient at redirecting luminescence from single luminophores. In the case of isolated metal nanoparticles, the plasmon resonances provide high local fields close to the particles.…”