Fabrication of optical waveguides inside transparent silica xerogels containing PbS quantum dots using a femtosecond laser

The fabrication and photoluminescence properties of waveguide structures inside transparent silica xerogels containing PbS quantum dots (QDs) have been investigated. Stable dispersion of water-soluble PbS QDs, which emit in the wavelength region of 1.3 mu m, in silica xerogels was conducted by a sol-gel method using 3-aminopropyl-trimethoxysilane. It was found that both the photoluminescence intensity and the dispersion stability are highly sensitive to catalysts, reaction temperature and time, and annealing temperature. Continuous and straight waveguide structures with refractive-index change were obtained by choosing appropriate irradiation conditions. The fabricated waveguides led approximately 60% increase in the intensity of the photoluminescence generated from the PbS QDs.