Spectroscopic investigations of LaAlO3_3:Eu3+^{3+}

RADIOC

Spectroscopic investigations of LaAlO3_3:Eu3+^{3+}

RADIOC

Spectroscopic properties of LaAlO3 doped with Ho3+

RadiochAbsorption and emission as well as emission decay times of Ho3+ ions embedded in LaAlO3 single crystal were measured. The experimental results were analysed in the frame of the Judd–Ofelt theory. Energy levels, oscillator strengths and probabilities of radiative transitions were determined. The results indicate on nonradiative transitions due to cross-relaxation down and up-conversions processes

Visible anti-Stokes emission of Gd3+ in Cs2NaGdCl6 crystal

Visible emission, assigned to the transitions between the upper excited levels of Gd3+ in the Cs2NaGdCl6 crystal upon excimer laser excitation, was observed. The emitting level is covered by the intense 4f(6)5d bands. The observed anti-Stokes transitions result from a two-photon absorption, the nature of which is discussed. Two mechanisms may have contributed to the observed visible signal: excited state absorption and two-photon absorption where the intermediate state belongs to the 4f(7) configuratio

Visible anti-Stokes emission of Gd3+ in Cs2NaGdCl6 crystal

Visible emission, assigned to the transitions between the upper excited levels of Gd3+ in the Cs2NaGdCl6 crystal upon excimer laser excitation, was observed. The emitting level is covered by the intense 4f(6)5d bands. The observed anti-Stokes transitions result from a two-photon absorption, the nature of which is discussed. Two mechanisms may have contributed to the observed visible signal: excited state absorption and two-photon absorption where the intermediate state belongs to the 4f(7) configuratio

Blue emission of Pr3+ ions in LaCl3 crystal triggered by U3+

An anti-Stokes emission in LaCl3:Pr3+ was found after excitation by a laser line resonant with the H-3(6)-->P-3(0) transition. The intensity of the blue emission was enhanced by three orders of magnitude when U3+ was added into the crystal. A mechanism for the up-conversion observed is discussed as well as the possibility of an avalanche process in Pr3+ triggered by U3+ ions

Spectroscopic properties of U3+^{3+} ions in a ZnCl2_2-based - glass

A ZnCl/sub 2/-based glass sample doped with U/sup 3+/ ions was prepared by mixing ZnCl/sub 2/, PbBr/sub 2/, KBr and UCl/sub 3/ in an appropriate stoichiometry and by melting the mixture at 450 degrees C under vacuum. Absorption and luminescence spectra of the sample have been measured at 300 and 15 K, respectively. The absorption spectrum is typical for U/sup 3+/ complex compounds in non-aqueous solutions. The emission bands observed at 14 250, 13 100, 8100, 7000 and 4170 cm/sup -1/ have been assigned to the transitions from the lowest components of the /sup 4/F/sub 9/2/, /sup 4/G/sub 7/2/, /sup 4/I/sub 13/2/, /sup 4/F/sub 3/2/ and /sup 4/I/sub 11/2/ multiplets to the Stark components of the /sup 4/I/sub 9/2/ ground multiplet. Decay curves of the visible emission were strongly non-exponential. The decay time of the longest component of the decay profile was found to be equal to 7 mu s and 800 ns at 10 and 300 K, respectively. Good agreement between the observed and calculated oscillator strengths has been obtained in an analysis of the f-f band intensities based on the Judd-Ofelt theory