Single-molecule controlled emission in planar plasmonic cavities

Abstract

We study the fluorescence emission from single dye molecules in coplanar plasmonic cavities composed of a thin gold film surrounded by two in-plane surface plasmon Bragg mirrors. We first discuss the effect of the presence of Bragg mirrors on the radiation diagram of surface plasmon coupled emission. Then, we investigate the role of the planar cavity size by single-molecule fluorescence lifetime imaging. Experimental data are compared to numerical simulations of the decay rates calculated as a function of the molecule orientation and position within the cavity. The creation of new decay channels by coupling to the cavity modes is also discussed. We measure a plasmonic Purcell factor up to five, attributed to the enhancement of the radiative rate.

Spatially uniform enhancement of single quantum dot emission using plasmonic grating decoupler

“…1(a) and ref. 15 ). QDs were imaged by using a confocal scanning microscope with an oil immersion 100X objective and numerical aperture (NA) of 1.3.…”

“…We first check the grating decoupling effect by imaging the emission diagram of the QDs by Fourier-plane leakage radiation microscopy (LRM) 15 20 . In order to obtain a sufficient signal to noise ratio (SNR) but keeping a controlled positioning of the QDs (determined by the size of the box), we considered ~5 QDs instead of single one deposited on the grating.…”

“…To date, various plasmonic structures have been investigated for the engineering of the spontaneous emission: nano-aperture 5 6 , random film 7 , plasmonic antenna 8 9 10 11 12 , circular grating 13 14 , in-plane cavity 15 , etc. All these devices relie on both the strong electromagnetic mode confinement that induces a large modification of the fluorescence emission rate and surface plasmon (de)coupled emission (SPCE) 16 to improve the collection efficiency.…”

Plasmonic Purcell factor and coupling efficiency to surface plasmons. Implications for addressing and controlling optical nanosources

“…Finally, a planar plasmonic cavity relies on the confinement of the SPP surface waves instead of confining a bulk mode for an optical micro-cavity. This additionnal mode confinement leads to a significant increase of the decay rate inside the cavity [121]. This is however at the price of strong losses.…”

Enhanced and polarized emission from single colloidal CdSe/CdS nanocrystals coupled to a one-dimensional gold grating

“…To check this, we estimate the total decay rate using Green's dyad formalism (see Refs. [21][22][23] for details). Figure 5(a) shows the modification of the 2D local density of states (LDOS) due to the addition of the grating on the flat gold film for a vertically oriented dipole.…”