Absorption spectral studies of rare earth ions (Pr3+, Nd3+, Sm3+, Dy3+, Ho3+ and Er3+) doped in NASICON type phosphate glass, Na4AlZnP3O12

The absorption spectral studies have been performed for rare earth (Pr3+, Nd3+, Sm3+: Dy3+, Ho3+ and Er3+) doped NASICON type phosphate glass, Na4AlZnP3O12 (NAZP) to derive the phenomenological Judd-Ofelt parameters Omega(lambda) (lambda = 2, 4, 6). The variation of Omega(2) values with f electrons shows a pronounced rise in the middle of the series arises due to the differences in the distribution of sires occupied by the rare earth ions in the present phosphate glass. The hypersensitive nature of absorption transitions of Nd3+, Er3+ and Ho3+ are explained in the light of covalency and site asymmetry effects. Emission studies of Eu3+ and Dy3+ indicate that these rare earths are situated in highly distorted sites compared to other fluoride, phosphate and oxyfluoride glasses. (C) 2000 Elsevier Science B.V. All rights reserved.