Enhancing the radiative emission rate of single molecules by a plasmonic nanoantenna weakly coupled with a dielectric substrate

Abstract

Enhancing the spontaneous emission of single emitters has been an important subject in nano optics in the past decades. For this purpose, plasmonic nanoantennas have been proposed with enhancement factors typically larger than those achievable with optical cavities. However, the intrinsic ohmic losses of plasmonic structures also introduce an additional nonradiative decay channel, reducing the quantum yield. Here we report on experimental studies of a weakly coupled dielectric substrate and a plasmonic nanoantenna for enhancing the radiative decay rate of single terrylene molecules embedded in an ultrathin organic film. We systematically investigate how the refractive index of the dielectric substrate affects the lifetime and the quantum efficiency and show that the coupled structure could moderately enhance the radiative decay rate while maintaining a high quantum efficiency.

Quantum Plasmonic Sensors

“…The inset shows a plasmon spectrum of a AuNP (black), the fluorescence spectrum of a single terrylene molecule (red), and the excitation laser line (green). Reproduced and adapted with permission from refs and . Copyright 2009 American Chemical Society and Copyright 2015 The Optical Society.…”

Dielectric Microsphere Coupled to a Plasmonic Nanowire: A Self‐Assembled Hybrid Optical Antenna

“…[ 4,5 ] These hybrid structures have been utilized, to design single photon devices, [ 6–8 ] optical antenna, [ 9,10 ] to tune the photoluminescence dynamics of emitters [ 11,12 ] and for enhanced spontaneous emission from emitters [ 13–15 ] down to the level of single molecule with minimized ohmic losses. [ 16,17 ]…”

“…[4,5] These hybrid structures have been utilized, to design single photon devices [6][7][8] , optical antenna [9,10] and for enhanced spontaneous emission from molecules [11,12] [ 13] down to the level of single molecule with minimized ohmic losses. [14,15] In this paper, we introduce a self-assembled, hybrid photonic structure: dye moleculecoated silica microsphere coupled to a plasmonic-silver nanowire. The coated microspheres facilitate whispering gallery mode (WGM) resonances and silver nanowire provides propagating plasmons.…”

Optical characterization of a single molecule complete spatial orientation using intra-molecular triplet–triplet absorption

“…22 This thin film configuration paved the way for pioneering nanophotonics experiments, enabling the quantitative measurement of the influence of nanoantennas on the very same single molecule, through scanning probe microscopy. 23,24 Furthermore, the thin film configuration allowed the integration of single Tr molecules as tools to inverstigate the impact of more complex structures on their emission properties and photophysics, such as plasmonic nanoparticles, [23][24][25][26] dielectric and metallic local probes, 27 planar dielectric antennas, 28 or hybrid nanostructures. 29 In our specific case, the thin film configuration is particularly appealing as it provides a good knowledge of the excitation electric field distribution.…”