Absorption spectra and luminescence of oxygen-deficient centres in titanosilicate glass synthesised in a steady laser plume. II. Luminescence

Abstract

The luminescence spectra of titanosilicate glasses, grown in a steady laser plume in an atmosphere of air or nitrogen at normal pressure, were investigated in the spectral range 260–500 nm. The luminescence was excited by the second harmonic of a cw Ar+ laser (λ =257nm) and was observed for glasses synthesised in air and nitrogen atmospheres throughout the investigated range of the titanium concentrations by weight (from ∼0.1% to ∼6%). When the titanium concentration was less than 1%, the luminescence spectrum of glass grown in a nitrogen atmosphere had a band with a maximum at λ ∼ 280 nm associated with silicon oxygen-deficient centres and a correlated new strong band with a maximum at λ ∼ 380 nm. An increase in the Ti concentration from ∼0.1% to ∼0.4% resulted in an exponential fall (by a factor of ∼4) of the intensity of the 280 nm luminescence band accompanied by a rise of approximately 30% in the intensity of the luminescence in the 380 nm band. Luminescence in the range 350–500 nm was observed in glass grown in a nitrogen atmosphere when the titanium concentration was ∼1%—2%. Glass grown in air there had a wide band in the luminescence spectrum and its maximum was near ∼ 440 nm (titanium concentration ∼2%) and a band attributed to the Ti4+ luminescence (with a maximum near ∼420 nm when the titanium concentration was 3%—6%).