Molecular fluorescence above metallic gratings - art. no. 125405

We present measurements of the fluorescence of emitters located in close pr oximity (d<<lambda>) to metallic grating surfaces. By measuring both the sp ontaneous emission lifetime and angle-dependent radiation pattern of a mono layer of dye molecules as a function of their separation from planar and pe riodically corrugated mirrors of increasing modulation depth, we are able t o examine the effect of varying the surface profile on the emission process . Both the distance dependence of the lifetime and the spatial distribution of the emitted light are significantly changed upon the introduction of a corrugation, quite apart from the appearance of the familiar Bragg-scattere d bound-mode features. It is postulated that these perturbations arise from the interference of the grating scattered dipole fields with the usual upw ard propagating and reflected fields. In addition. the measurement of nonex ponential decay transients for the deepest gratings examined provide eviden ce for the existence of optically dissimilar dipole positions above the gra ting surface.