Engineering the light-transport mean free path in silica photonic glasses

Abstract

A method for tailoring the resonant transport of light in photonic glasses (PGs) was introduced, which consisted of infiltrating the material with conformal layers of silica using CVD. If the infiltration degree is kept below a critical level, the spectral position of the resonances could be tuned finely without severely affecting their contrast. A calibration of the number of CVD cycles, the thickness of the silica layer deposited, and the displacement of the resonances was suggested, which should be optimized for different particles size, surface composition, or environmental conditions when applying this method to design PG properties. Additionally, the procedure resulted in an increase of the total transmittance of the sample and the transport mean free path, which were stepwise monitored. The experiment resulted in a change of transport mean free path in a range almost as high as one order of magnitude. We propose the possibility of using this method for tuning the amplified emission of PGs incorporating optical gain.