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The electron absorption-, photoluminescence- and electron paramagnetic-resonance spectra of Mn3+ in red beryl from Wah Wah Mountains (Utah USA) and of pink- and purple vesuvianite from Jeffrey Mine (Asbestos, Canada) were measured at room- and low temperatures. The crystal field stabilization energies are equal to 130.9 kJ/mol for the red beryl, and 151.5-158.0 and 168.0 kJ/mol for for the pink- and the purple vesuvianite, respectively. The red photoluminescence of Mn3+ was not intensive either at room- or at low temperatures. The high Mn content in the crystals caused the emergence of an additional emission band and short photoluminescence-decay lifetimes. The latter are only 183 μs for beryl and 17 μs for vesuvianite. [ABSTRACT FROM AUTHOR]

Single crystal of LaGaTaO (LGT) containing intentionally 0.5 % of Ho and 1 % of Yb was grown by the Czochralski method. Examination of chemical composition of the grown crystal revealed that luminescent holmium and ytterbium ions are preferably retained in the melt and their actual concentrations are 0.12 and 0.24 %, respectively. Spectroscopic investigation performed encompassed IR host absorption spectra and Raman spectra at room temperature, optical absorption and luminescence spectra of Ho and Yb at room temperature and at 5 K, and luminescence decay curves at room temperature. It was found that all spectral bands recorded show important inhomogeneous line broadening. This feature was attributed to structural disorder inherent to the crystal lattice in which pentavalent Ta ions occupy octahedral Ga(1) sites together with trivalent Ga ions. Despite small concentrations of luminescent ions, the occurrence of nonradiative interaction that feeds the I and I levels of Ho ions by transfer of an excitation from the F level of Yb ions was evidenced. Based on examination of spectroscopic parameters evaluated, it was concluded that LGT:Ho, Yb may be considered as a potential intermediate-gain laser active material able to emit infrared radiation from the I → I transition of Ho around 2 micrometres upon laser-diode pumping into Yb absorption band. [ABSTRACT FROM AUTHOR]

For the first time ever, the luminescence spectra of Cr centers in two chlorite crystals are presented. Chromium ions occupy the strong crystal-field site M4 in the brucite sheet and the intermediate crystal-field site in the inner octahedral sheet for purple and green chlorite, respectively. We discuss the influence of an effective positive charge on the Cr ion and an effective negative charge of ligands on the differences in the values of the Dq and B parameters. It is concluded that the presence of Fe ions and other point defects, as well as concentration quenching, causes the very short luminescence lifetimes of chromium ions. [ABSTRACT FROM AUTHOR]

The goal of this work was to investigate the spectroscopic properties of Pr ions, embedded in two different tellurite glass matrices, TeO-WO-PbO-LaO and TeO-WO-PbO-LuO. The absorption and fluorescence spectra have been recorded and analyzed in terms of the Judd-Ofelt theory along with the luminescence decay of the P and D levels of the Pr ion. The spectroscopic studies were completed with ellipsometric measurements providing the dispersion relation of the refractive index of the investigated glasses. [ABSTRACT FROM AUTHOR]

There are many figures of merit, which determine suitability of luminescent thermometers for practical applications. These include thermal sensitivity, thermal accuracy as well as ease and cost effectivness of technical implementation. A novel contactless emission thermometer is proposed, which takes advantage of the coexistence of photoluminescence from Nd3+ doping ions and black body emission in transparent Nd3+ doped-oxyfluorotellurite glass host matrix. The opposite temperature dependent emission from these two phenomena, enables to achieve exceptionally high relative sensitivity SR = 8.2%/°C at 220 °C. This enables to develop new type of emissive noncontact temperature sensors. [ABSTRACT FROM AUTHOR]