Oriented prolate silver particles in glass - Characteristics of novel dichroic polarizers

Nanosized spherical silver particles in glass, introduced by an ion exchang e plus annealing procedure, have been deformed at elevated temperatures to uniformly arranged prolate spheroidal particles by homogeneous glass stretc hing at constant stress. Thereupon, the optical absorption band splits into two bands according to the long and short mes of the deformed particles. S ince colour and polarizing effect of these particles may widely be controll ed by variation of their aspect ratio this technique enables the fabricatio n of novel dichroic polarizers with spectral characteristics throughout the whole visible range. Local thermally induced shape relaxation of deformed particles makes colour structuring possible on the micrometer scale. Charac terisation of these materials by optical absorption spectroscopy and transm ission electron microscopy demonstrates the influence of deformation and sh ape relaxation on their spectral and polarizing properties. (C) 1999 Acta M etallurgica Inc.