We report on enhanced fluorescence of lead sulfide quantum dots interactingwith leaky modes of slab-type silicon photonic crystals. The photonic crystalslabs were fabricated supporting leaky modes in the near infrared wavelengthrange. Lead sulfite quantum dots which are resonant the same spectral rangewere prepared in a thin layer above the slab. We selectively excited the leakymodes by tuning wavelength and angle of incidence of the laser source andmeasured distinct resonances of enhanced fluorescence. By an appropriateexperiment design, we ruled out directional light extraction effects anddetermined the impact of enhanced excitation. Three-dimensional numericalsimulations consistently explain the experimental findings by strong near-fieldenhancements in the vicinity of the photonic crystal surface. Our studyprovides a basis for systematic tailoring of photonic crystals used inbiological applications such as biosensing and single molecule detection, aswell as quantum dot solar cells and spectral conversion applications.
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