Formation of Photosensitive Layers in Alkali Germanate Glasses

Abstract

The induced optical absorption spectra of 70GeO 2 · 10Ga 2 O 3 · 20Li 2 O glasses are measured. A process is described for producing photosensitive layers on alkali germanate glasses using ion-exchange diffusion from salt melts containing silver nitrate. The effects of the sensitizer (Ce 3+ , Fe 3+ , and Fe 2+ ) and preparation, UV irradiation, and heat treatment conditions on the mechanisms of silver reduction in the surface layer of germanate glasses are examined. The results demonstrate that colloidal silver particles can be produced via ion exchange at 350 ° C in glasses containing 0.1 wt % Fe 2 O 3 . The particle diameter in a glass prepared under reducing conditions is estimated at 2.5 nm.

Er3+-doped germanate glasses for active waveguides prepared by Ag+/K+↔Na+ ion-exchange

“…They studied the composition containing 65.5GeO 2 -12Al 2 O 3 -4.5BaO-18Na 2 O (mol%), measured mode profiles and propagation losses of the channel waveguides at 1.55 lm less than 2 dB/cm. Heavy metal germanate glasses have proved to be promising hosts for such applications since they combine many interesting properties such as high chemical durability, temperature stability and large transparency window in the infrared region [10,13] relatively lower phonon energy (800-900 cm À1 ) than those of silicate, borate and phosphate glasses [14][15][16]. The relative low phonon energy of germanate glasses leads to increasing Er 3+ emission quantum efficiency [17,18] since non-radiative decays become less important.…”