Optical absorption and photoluminescence properties of Dy3+-doped alkali borate: 59 H3BO3 + 30 Li2CO3 + 10 Al2O3 + 1 Dy2O3 (Glass-A) and alkali fluoroborate: 59 H3BO3 + 30 LiF + 10 Al2O3 + 1 Dy2O3 (Glass-B) glasses have been investigated. From the measured absorption spectra, the oscillator strengths are determined from the area under the absorption bands. Judd-Ofelt analysis was applied and the intensity parameters (×10−20 cm2) Ω2 = 4.620, Ω4 = 2.706, Ω6 = 2.087 and Ω2 = 5.306, Ω4 = 2.027, Ω6 = 1.511 for glasses A and B, respectively were evaluated with a reasonable agreement between the measured and calculated f-values. These parameters were used for the calculation of radiative transition rates (AR), branching ratios (βR), radiative lifetimes (τR) and integrated absorption cross-sections (Σ) for the 4F9/2, 6H5/2, 6H9/2, 6F11/2, 6H11/2 and 6H13/2 electronic excited states and are compared with those of other glasses reported in the literature. From the radiative spectroscopic parameters, it is predicted that these Dy3+-doped glasses A and B are found to be more attractive for blue–green solid-state laser devices.

Spectroscopic and laser properties of Pr3+ ions incorporated into tellurofluorophosphate (TFP) glasses have been investigated from the absorption and emission spectra recorded in the UV–VIS–NIR regions. The intensities of the 4f–4f induced electric dipole transitions are parametrized in terms of Judd–Ofelt intensity parameters Ωλ (λ=2, 4, 6) from the experimentally determined oscillator strengths. Various spectroscopic parameters such as electric dipole linestrengths (Sed), magnetic dipole linestrengths (Smd), radiative transition probabilities (AR), radiative lifetimes (τR), branching ratios (βR) and integrated absorption cross-sections (σa) for stimulated emission were evaluated for various excited levels of Pr3+ ions. The effect of compositional changes of the glasses on the optical properties of Pr3+ ions has been discussed. These calculated intensity parameters (Ωλ) and radiative lifetimes (τR) are compared with other Pr3+ doped host materials. From the magnitudes of the stimulated emission cross-sections (σe), branching ratios (βR), the most potential laser transitions are identified and utility of these glasses as laser active materials is discussed.

Absorption and emission properties of Pr3+ doped mixed alkali chloroborophosphate glasses have been reported in the UV-VIS-NIR region. A modified Judd–Ofelt (JO) approach has been employed to evaluate the intensity parameters Ωλ, from the experimentally determined oscillator strengths. These parameters are compared with those obtained from the standard JO theory. The evaluated JO parameters are utilized for the calculation of various radiative parameters such as radiative transition rates (AR), radiative lifetimes (τR), fluorescence branching ratios (βR) and the integrated absorption cross-section (∑) for stimulated emission from different excited states of Pr3+ ion. From the measured emission spectra, the principal fluorescence transitions of interest are identified and their stimulated emission cross-sections (σe) and branching ratios (βR) were determined. The measured branching ratios are in close agreement to the branching ratios predicted by the modified JO parameters. From these investigations, it is observed that the modified JO theory provides the positive values for the Ω2 parameters and also significant improvement between the measured and calculated oscillator strengths.

Optical absorption spectra were studied in wavelength region 400–900 nm for the Nd3+-doped alkali (R=Li, Na and K) chloroborophosphate glasses at room temperature. The energy level scheme of the 4f3 electron configuration was deduced from the observed energy level data using a parametrized Hamiltonian (HF1) model which includes 20 free-ion interaction parameters. Reasonable correlation was obtained between the experimental and calculated energy levels. The Judd–Ofelt model for the intensity analysis of induced electric dipole transitions has been applied to the measured oscillator strengths of the absorption bands to determine the three phenomenological intensity parameters Ω2, Ω4 and Ω6 for each glass. Using these parameters, the total radiative transition rates (AT), non-radiative relaxation rates (WNR), branching ratios (βR), integrated cross-sections for the stimulated emission (Σ), excited state emission intensities (fESE) and excited state absorption intensities (fESA) have been theoretically calculated for certain excited Nd3+ fluorescent levels. From the results obtained, the conclusion is made about the possibility of using these glasses as laser media.

Optical properties of Dy3+ doped zinc phosphate glasses have been investigated. In the present study glasses with the composition xZnO·(1−x)P2O5 (0.5⩽x⩽0.7) (typical value of x=0.667) containing 0.5 mol weight of Dy2O3 are prepared. The density of the glass is determined by Archimedes’s principle and the refractive index is measured on Abbe refractometer using sodium lamp as light source. The optical absorption spectra are recorded on a Hitachi U-3400 spectrophotometer in the wavelength range 200–2500 nm. Using the Judd–Ofelt (JO) theory, the intensity parameters (Ωλ, λ=2, 4,6) have been evaluated for the glass. These intensity parameters are used to predict radiative properties that include electric (Sed) and magnetic (Smd) dipole line strengths, radiative (A) and total radiative (AT) transition probabilities, lifetimes (τR), branching ratios (βR) for the excited (6H11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2) levels of these Dy3+ doped phosphate glass.

Alkali chloroborophosphate glasses containing 1 mol% of Er3+ ions were studied experimentally using the absorption and emission spectroscopy. The energy level scheme for the 4f11 (Er3+) electronic configuration was deduced from the observed band energies of the absorption spectra in terms of a parametrized Hamiltonian using the various free-ion spectroscopic parameters. Oscillator strengths (f) measured from the absorption spectra have been analyzed using the Judd–Ofelt theory to evaluate the three intensity parameters Ωλ (λ=2, 4 and 6). Reasonable agreement between the measured and calculated f values has been found. Electric and magnetic dipole transition probabilities, fluorescence branching ratios, integrated emission cross sections and radiative lifetimes were calculated for all the excited states of Er3+ ions. The non-radiative (WNR) relaxation rates from the excited levels to the next lower levels have been calculated and the relationship between the energy gap and non-radiative relaxation rate has been established. These results were used to predict the possible potential laser transitions in Er-doped alkali chloroborophosphate glasses.

Alkali chloroborophosphate glasses containing 1 mol% PrCl3 were prepared and their absorption and emission spectra measured at room temperature. The energy level scheme of the 4f2 electronic configuration of Pr3+ was parameterized in terms of 14 free-ion parameters using the free-ion Hamiltonian model (HFI). From the measured oscillator strength of the absorption bands, the three phenomenological Judd–Ofelt parameters Ωλ (λ=2, 4 and 6) were determined by the standard least-squares fit procedure. With the knowledge of these intensity parameters, the radiative transition probabilities, radiative lifetimes, branching ratios, integrated cross sections for stimulated emission and peak emission cross sections were calculated. The obtained data are used to discuss the radiative and non-radiative properties of certain excited luminescent levels of Pr3+ in alkali chloroborophosphate glasses and possible laser transitions are identified.