Optical properties of Nd3+-doped fluorophosphate glasses

Optical absorption spectra of Nd3+-doped fluorophosphate glasses of the type 75NaPO(3)-24AF-1NdF(3) (A=Li, Na, K) and of the type 75NaPO(3)-24AF(2)-1NdF(3) (A=Ca, Sr, Ba, Zn, Cd) have been recorded. The dipole strengths are parameterised in terms of three phenomenological Judd-Ofelt intensity parameters Omega(lambda) (lambda=2, 4 and 6). With the knowledge of these intensity parameters, the probability for spontaneous emission, the branching ratios and the radiative lifetime are calculated. The relation between the spectral intensities and the glass composition is discussed. The optical properties of the fluorophosphate glasses are compared with those of phosphate and fluoride glasses. It is shown that the choice of the cation only has a minor influence on the spectral intensities. The spectral behaviour of the fluorophosphate glasses is intermediate between the spectral behaviour of pure phosphate and fluoride glasses. (C) 1998 Elsevier Science S.A.