Preparation of Cerium‐Activated Silica Glasses: Phosphorus and Aluminum Codoping Effects on Absorption and Fluorescence Properties

Abstract

Cerium‐activated silica (SiO 2 ) glasses were prepared by plasma torch chemical vapor deposition (CVD). In Ce‐doped SiO 2 glasses, most Ce exists as Ce 4+ ions; the remaining small amount of Ce 3+ ions exhibits a broad fluorescence spectrum with a large Stokes shift, ∼9600 cm ‐1 , from the excitation spectrum peak of 324 nm. Aluminum and phosphorus codoping considerably increases the Ce 3+ ratio and shifts the peaks of both spectra to shorter wavelengths. P codoping is the more effective way to achieve this result and in some cases produces an absorption spectrum similar to that of a Ce‐doped phosphate glass. These findings are consistent with the solvatiorn shell model for codoping, as previously proposed. To codope P, a soot remelting method was devised to deal with the highly volatile P 2 O 5 .