Fluorophores-modified silica sphere as emission probe in photonic crystals

The spontaneous emission of fluorophores embedded in a photonic crystal has been studied. By nano-engineering a sandwich-like photonic structure, such that fluorescent spheres constitute a middle layer between the photonic crystals, we can precisely control the location of fluorophores in photonic crystals and exclude the presence of fluorophores near the crystal surface. It has been found that the stopband in the transmission spectrum is deeper than the stopband in the emission spectrum. We conjecture that the omni-directional propagation of the emission from a point source in an incomplete photonic bandgap is the cause of the shallower stopband in emission.