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Fluoroindate glasses co-doped with Pr3+/Er3+ ions were synthesized and their near-infrared luminescence properties have been examined under selective excitation wavelengths. For the Pr3+/Er3+ co-doped glass samples several radiative and nonradiative relaxation channels and their mechanisms are proposed under direct excitation of Pr3+ and/or Er3+. The energy transfer processes between Pr3+ and Er3+ ions in fluoroindate glasses were identified. In particular, broadband near-infrared luminescence (FWHM = 278 nm) associated to the 1G4 → 3H5 (Pr3+), 1D2 → 1G4 (Pr3+) and 4I13/2 → 4I15/2 (Er3+) transitions of rare earth ions in fluoroindate glass is successfully observed under direct excitation at 483 nm. Near-infrared luminescence spectra and their decays for glass samples co-doped with Pr3+/Er3+ are compared to the experimental results obtained for fluoroindate glasses singly doped with rare earth ions. [ABSTRACT FROM AUTHOR]

The influence of Cr3+ concentration on near-infrared emission of Ho3+ in barium gallo-germanate glass has been studied. Near-infrared emission bands, due to 4T 2 → 4A 2 (Cr3+) as well as 5I 6 → 5I 8 and 5I 7 → 5I 8 (Ho3+) transitions, were observed under excitation of Cr3+. The enhanced and broadband near-infrared emission was obtained for glasses in the presence of transition metal (Cr3+) and rare earth (Ho3+) ions. This prosperity was optimized as a function of donor (Cr3+) and acceptor (Ho3+) concentration. The integrated intensities of emission bands were determined and their values are found to be maximal at 0.25 mol% Cr3+ and 0.5 mol% Ho3+. The energy transfer from Cr3+ to Ho3+ occurs through a nonradiative process with an efficiency up to 23%. • Cr3+/Ho3+ co-doped barium gallo-germanate glasses were studied for NIR emission. • NIR emission spectra of Ho3+ ions in glasses were measured under excitation of Cr3+. • Emission bands are due to 4T 2.→ 4A 2 (Cr3+), 5I 6 → 5I 8 and 5I 7 → 5I 8 (Ho3+) transitions • The relative emission band intensities of Ho3+ depend critically on Cr3+ concentration. • The energy transfer from Cr3+ to Ho3+ with an efficiency up to 23% occurs. [ABSTRACT FROM AUTHOR]

Near-infrared luminescence properties of Nd 3+ and Ho 3+ ions in barium gallo-germanate glasses have been reported. Several spectroscopic parameters for Nd 3+ and Ho 3+ ions have been determined from the Judd-Ofelt analysis and absorption/luminescence measurements. Quite large luminescence lifetime, quantum efficiency and stimulated emission cross-section have been obtained for the main 4 F 3/2  →  4 I 11/2 (Nd 3+ ) and 5 I 7  →  5 I 8 (Ho 3+ ) laser transitions of rare earths in barium gallo-germanate glasses. It suggests that barium gallo-germanate glass is promising for near-infrared laser application at emission wavelengths 1064 nm (Nd 3+ ) and 2020 nm (Ho 3+ ). [ABSTRACT FROM AUTHOR]

Luminescence properties of Pr 3+ ions in germanate glasses modified by BaF 2 were investigated. Several luminescence bands originating to transitions from the 3 P 0 state to the lower-lying states of Pr 3+ were registered under 450 nm excitation. The spectral analysis suggests that the positions of luminescence bands and their relative intensities are changed significantly with BaF 2 content. The relative integrated luminescence intensities of 3 P 0 → 3 H 4 transition (blue) to the 3 P 0 → 3 F 2 transition (red) of Pr 3+ ions strongly depend on fluoride modifier BaF 2 in glass composition. The luminescence bands of Pr 3+ ions are shifted to shorter wavelengths with increasing BaF 2 content. [ABSTRACT FROM AUTHOR]

Lead-free oxyfluoride borate glasses singly doped with Pr 3+ and Er 3+ were prepared and next investigated using absorption and luminescence spectroscopy. In the studied glass system, barium oxide was substituted by BaF 2 . Two luminescence bands of Pr 3+ located at visible spectral region are observed, which correspond to 3 P 0 – 3 H 4 (blue) and 1 D 2 – 3 H 4 (reddish orange) transitions, respectively. The luminescence bands due to 1 D 2 – 3 H 4 transition of Pr 3+ are shifted to shorter wavelengths, when BaO was substituted by BaF 2 . Near-infrared luminescence spectra of Er 3+ ions in lead-free borate glasses modified by BaF 2 correspond to 4 I 13/2 – 4 I 15/2 transition. Their spectral linewidths increase with increasing BaF 2 concentration. The changes in measured lifetimes of rare earth ions are well correlated with the bonding parameters calculated from the optical absorption spectra. [ABSTRACT FROM AUTHOR]

• Pr3+/Er3+ co-doped glass based on InF 3 have been studied • Emission spectra of Pr3+/Er3+ were measured under different excitation wavelengths • Energy transfer process from Pr3+ to Er3+ occurs • Pr3+/Er3+ co-doped glass based on InF 3 are promising for white light emission Pr3+/Er3+ co-doped glasses based on InF 3 were synthesized and then studied for white light emission. The emission spectra consist of several bands corresponding to characteristic 4f-4f electronic transitions of Pr3+ and Er3+ ions. The relative intensities of emission bands depend on the selective excitation wavelengths. The energy transfer process from Pr3+ to Er3+ ions was confirmed by the excitation and emission spectra measurements. From emission spectra, the CIE chromaticity coordinates, the correlated color temperature (CCT) and the color purity (CP) were determined. The results indicate that Pr3+/Er3+ co-doped glasses based on InF 3 are excellent fluoride candidate to achieve warm white light emission. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

Spectroscopic properties of rare earths in lead-free oxyfluoride germanate glasses were studied. The absorption and luminescence spectra of Eu 3+ , Pr 3+ and Er 3+ ions were examined as a function of BaF 2 concentration and several spectroscopic parameters for rare earths were determined. The ratio of integrated luminescence intensity of the 5 D 0 → 7 F 2 transition to that of the 5 D 0 → 7 F 1 transition of Eu 3+ decrease significantly with increasing BaF 2 content. The absorption (Er 3+ ) and emission (Pr 3+ ) ‘hypersensitive transitions’ of rare earths are shifted in direction to shorter wavelengths with increasing BaF 2 content in glass composition. Emission spectra and their decays corresponding to the main 4 I 13/2 → 4 I 15/2 laser transition of Er 3+ were also analyzed. Quite long-lived NIR luminescence of Er 3+ is observed for lead-free glass samples with low BaF 2 concentration. [ABSTRACT FROM AUTHOR]