[Spectroscopic properties of Pr3+ doped transparent oxyfluoride vitroceramics].

In the present paper, the room-temperature absorption spectrum of Pr+ -doped transparent oxyfluoride vitroceramics (Pr(0.2):FOV) was studied systematically. The optical characterisation of Pr(0.2):FOV was performed. The standard and modified Judd-Ofelt theories were used to determine the J-O intensity parameters. The problems with standard Judd-Ofelt theorie for Pr3+ were discussed. Based on the intensity parameters, some predicted optical parameters, such as the spontaneous radiative transition probabilities, radiative lifetimes, branching ratios and integrated emission cross section were calculated. And the application of Pr:FOV was analyzed. Especially there are large oscillator strength and large integrated emission cross section in the transitions of (3)P0-->(3)H4, (3)P1-->(3)H5 and (3)P0-->(3)H6, (3)P0-->(3)F2. So, they are more worthy of attention. The obtained spectroscopic results show the potential application of the Pr3+ -doped oxyfluoride vitroceramics for solid-state lasers.

[Optical parameters of Er3+ in Er3+ : YVO4].

In the present paper the authors firstly measured the absorption spectra of Er3+ in the sample Er3+ : YVO4 (0.5%), then calculated the intensity parameters are calculated by using the Judd-Ofelt theory. After that the authors dealed with some predicted spectroscopic parameters, such as the oscillator strength, spontaneous radiative transition rate, branching ratio and integrated emission cross section. And Er : YVO4 crystal application value has been analyzed with the optical parameters. Especially there are large oscillator strengths and large integrated emission cross sections in the transitions of 4 I1/2 --> 4 I15/2, 2 H11/2 --> 4I15/2, 4S3/2 --> 4 I15/2, and 4F9/2 --> 4 I15/2. So, they are more worth of attention. Moreover, by comparing the Er-doped yttrium vanadate crystal and other Er-doped crystal optical properties, the authors can see the advantages of YVO4 as laser crystal. Finally, the authors discussed the splitting of the energy levels of Er3+ in the crystal YVO4 based on the group theory.

[The upconversion luminescence of Tm(0.35)Yb(5):FOV nanophase oxyfluoride vitroceramics].

The upconversion luminescence of nanophase oxyfluoride vitroceramics Tm(0.35)Yb(5) : FOV when excited by a 975 nm diode laser was studied in the present paper. Several ultraviolet upconversion luminescence lines positioned at 363.6 nm, (462.6 nm, 477.0 nm), 648.7 nm, (699.7 nm, 680.7 nm) and (777.6 nm, 800.7 nm) were found. They can be attributed to the fluorescence transitions of 1 D2-->3 H6, 1 G4-->3 H6, 1 G4-->3 F4, 3 F3-->3 H6 and 3 H4-->3 H6 of Tm3+ ion. The careful measurement and analysis of the variation of upconversion luminescence intensity F as a function of the 975 nm pumping laser power P has proven that the upconversion luminescence of 1 D2 state is partly a five-photon upconversion luminescence, while the upconversion luminescence of 1 G4 and 3 H4 state is the three-photon and two-photon upconversion luminescence respectively.