Near-infrared luminescence of rare earth ions in oxyfluoride lead borate glasses and transparent glass-ceramic materials

Oxyfluoride lead borate glasses singly doped with Nd3+ and Er3+ ions have been studied before and after thermal treatment. The orthorhombic PbF2 crystallites are formed during thermal treatment, which was evidenced by X-ray diffraction analysis. Near-infrared luminescence spectra at 1.06 μm and 1.53 μm have been registered for samples before and after annealing, which correspond to the main 4F3/2–4I11/2 and 4I13/2–4I15/2 laser transitions of Nd3+ and Er3+ ions, respectively. Luminescence decays from 4F3/2 state of Nd3+ and 4I13/2 state of Er3+ have been analyzed in detail. Contrary to Nd-doped samples, the luminescence lines obtained for Er-doped transparent oxyfluoride glass-ceramics are more intense and narrowed, whereas the luminescence decays from 4I13/2 state of Er3+ are slightly longer in comparison to precursor glasses

Influence of PbX2 (X = F, Cl, Br) content and thermal treatment on structure and optical properties of lead borate glasses doped with rare earth ions

Oxyhalide lead borate glasses doped with rare earth ions have been studied before and after thermal treatment. The rare earths as optically active ions were limited to the Er3+ ions. Near-infrared luminescence due to the main 4I13/2–4I15/2 laser transition of Er3+ was registered. The introduction of PbX2 to the borate glass results in a reduction of spectral linewidth and an increase of luminescence lifetime of 4I13/2 state of Er3+ ions. The unusual large spectral linewidth for 4I13/2–4I15/2 transition of Er3+ in the oxide glass host was obtained, whereas the luminescence decay from 4I13/2 state is longer for a sample with PbF2 than PbCl2 and PbBr2. Heat treatment introduces transformation from a glass to transparent glass-ceramic (TGC). The coordination sphere around Er3+ ions is changed, giving important contribution to the luminescence characteristics. The spectroscopic consequence of this transformation is the increase of luminescence lifetime and the narrowing of spectral lines of Er3+

Relaxation of the 4\text{}^{4}S3/2\text{}_{3}\text{}_{/}\text{}_{2} Level of Er3+\text{}^{3+} in Cs2\text{}_{2}NaErCl6\text{}_{6}

Octahedral (O$\text{}_{h}$) symmetry of the RE$\text{}^{3+}$ sites in the Cs$\text{}_{2}$NaRECl$\text{}_{6}$ crystals removes all of the electric dipole intensity from the 4f-4f transitions. Thus the decay of luminescence originating in the excited states of RE ions is governed by phonon assisted (vibronic) transitions, multiphonon relaxation and phonon assisted energy transfer (cross relaxation and energy migration to impurities). Contribution of these processes to the decay of the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ state of erbium in Cs$\text{}_{2}$NaErCl$\text{}_{6}$ has been studied in the 4.2-300 K temperature region. It has been concluded that at low temperatures the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ state decays exclusively by vibronic transitions. At about 100 K the cross relaxation via the $\text{}^{4}$I$\text{}_{9}\text{}_{/}\text{}_{2}$ state becomes operative. Efficiency of this process grows strongly with increasing temperature, reducing the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ lifetime by almost three orders of magnitude. No evidence has been found that multiphonon relaxations contribute to the decay of the $\text{}^{4}$S$\text{}_{3}\text{}_{/}\text{}_{2}$ state

Neodymium doped SrLaAlO4. A new promising crystal for laser application

Single crystals of neodymium doped SrLaAlO4 have been grown by the Czochralski method and investigated using the methods of optical spectroscopy. Absorption band centered at 806nm is particularly intense in this crystal and this feature seems to be advantageous for side pumping with GaAlAs laser diode bars. Available spectroscopic data indicate that excited states absorption might be of low importance in SrLaAlO4:Nd