Whispering gallery modes from CVD diamond spherical-like particles

The optical properties of diamond spherical-like particles, prepared by the hot-filament chemical vapor deposition technique on opal substrates, have been investigated. The particles were studied using scanning electron microscopy, micro-Raman spectroscopy and micro-photoluminescence techniques. The diamond particles, consisting of polycrystalline diamond, have a size of about 5 μm. Periodic peaks in the background of the photoluminescence spectra have been revealed. Analysis of the position of these peaks with the Lorentz–Mie theory for light scattering by single dielectric spherical particles confirms that these observed peaks can be regarded as whispering-gallery mode.