The preparation and optical properties of small silver particles in glass

The preparation of a large number of well characterized small silver particles in a photosensitive glass and in a stained glass is described. Particles with diameters from about 10 Å to greater than 100 Å were produced. Using the stained glass a volume fraction of particles of at least 1% can be obtained. The width and peak position of the optical absorption due to these particles was measured for different particle sizes. A significant shift in the peak position was observed for particles less than about 25 Å diameter. Both the width of the absorption and its position could be quite well described by a theory which assumes that the mean free path of the conduction electrons is proportional to the particle radius.