Abstract
The time resolved fluorescence spectra and their Nd3+ concentration CNd dependence were observed in Nd-doped SiO2 glasses prepared by plasma torch CVD. The 4F3/2 radiative emissions observed consist of a fast (FDC, τm≃0.35 µs) and a slow (SDC, τm≃470 µs) decay component. The FDC are characterized by the intensity ratio (4F3/2–4I11/2/4F3/2–4I9/2>1), but the SDC by the inverse ratio and the spectral shift to the longer wavelength. The SDC increases and reaches almost constant values in higher CNd. The FDC can not be observed in very low CNd region, but increases abraptly in higher CNd. The FDC is ascribed to the Nd3+ in the clustering microstructure and the SDC is ascribed to the isolated Nd3+ in crystal field unique to unitary SiO2 glass.