The efficiency of surface-plasmon coupled emission for sensitive fluorescence detection

Abstract

Surface-plasmon coupled emission (SPCE) has emerged as a new and potentially powerful tool for highly sensitive fluorescence detection. In the case of SPCE, the fluorescence is collected through a semi-transparent thin metal film deposited on glass. We present a theoretical analysis of SPCE, studying the potential enhancement of the fluorescence collection efficiency, brightness, quantum-yield, and photostability. The results are compared with fluorescence detection on a pure glass surface. It is shown that SPCE does not lead to any improvement, but that the metal film actually reduces the sensitivity of fluorescence detection.

Metal-enhanced fluorescence of an organic fluorophore using gold particles

“…A thin Au film (2 nm) displayed a plasmon absorbance at 600 nm (Fig. 1), close to the wavelength of nano-size individual particle, indicating that the thin film was indeed composed of nano-size particles [30][31][32]. The plasmon wavelength was red-shifted to 680 nm with increasing the thickness to 5 nm, showing that the particle size became larger for the thicker gold film (Fig.…”

Kinetics of a single cross-bridge in familial hypertrophic cardiomyopathy heart muscle measured by reverse Kretschmann fluorescence

“…46 Figure 1͑c͒ reveals that there is a weak peripheral ring, a diffuse interior, and strong central spot. The ring is due to weak coupling to a high refractive index glass, even in the absence of metal, 47 the diffuse interior is the image, and the central spot arises because a significant amount of exciting light is able to pass to the detector ͑the detector is looking directly at the laser; all the light impinging on a sample at 0-deg angle is passing through the center at BFP͒. The situation is quite different when a sample rests on a coverslip coated with a thin layer of metal ͓Fig.…”

A proposal and a theoretical analysis of an enhanced surface plasmon coupled emission structure for single molecule detection

“…Now, the detection volume in an SPCE system will directly depend on the product of two near-field factors: The penetration depth of the excitation field and the distance-dependent coupling of fluorophore radiation to the surface plasmons. The distancedependent coupling of the radiated power of fluorescence to SPCE varies with the distance of the fluorophore from the metal interface as a skewed bell-shaped relation, with its peak at ∼ 25 nm [4,13]. The full-width at half-maximum (FWHM) of the product of evanescent excitation field and the distance-dependent coupling for a typical SPCE structure is ∼ 50 nm [4,46].…”

“…However, although in an SPCE based fluorescence microscopy technique, light is emitted only in a sharply defined angle, the intensity of the emitted light is less due to loss in metal [13]. Therefore, detection of a biological sample is difficult when the excitation volume is very limited as in for SMD so that the number of fluorophores that radiate is less.…”