Levels Of Pr3 Research Articles

Pr3+ ions doped single alkali and mixed alkali fluoro tungsten tellurite glasses for visible red luminescent devices

The present work illustrates the optical absorption and fluorescence properties of Pr3+ ions doped single alkali and mixed alkali fluoro tungsten tellurite glasses prepared by using melt quenching technique. The prepared glasses were characterized by using absorption, excitation and photoluminescence (PL) spectral measurements. The energies of the absorption spectral features called oscillator strengths were calculated using area method and in turn used to evaluate the Judd-Ofelt (J-O) intensity parameters (Ω2, Ω4, Ω6). Such J-O parameters are used to estimate various radiative parameters such as radiative transition probabilities (AR), branching ratios (βR), and radiative lifetimes (τR) for the prominent fluorescent levels of Pr3+ ions in these glasses. The PL spectra of the as prepared glasses show three prominent peaks at wavelengths 488, 646 and 670 nm related to the transitions 3P0 → 3H4, 3P0 → 3F2 and 1D2 → 3H5 respectively for which emission cross-sections and branching ratios were evaluated. The variations in the spectral parameters with the variation of glass matrix composition have been examined in detailed. The decay profiles of the prepared glasses have been recorded to evaluate quantum efficiency of present series of glasses. From the measured branching ratios, emission cross-sections and quantum efficiency, it was concluded that the tungsten tellurite glasses added with potassium fluoride and doped with 1 mol% of Pr3+ions (TeWK glass) are quite suitable to produce visible red emission at 670 nm suitable to fabricate red luminescent devices.

Spectroscopic study of Pr3+ ions doped Zinc Lead Tungsten Tellurite glasses for visible photonic device applications

Zinc Lead Tungsten Tellurite (ZnPbWTe) glasses doped with different Pr3+ ion concentrations having the composition 5ZnO + 15PbO + 20WO3 + (60-x)TeO2 + xPr6O11 (where x = 0.5, 1, 1.5, 2.0 and 2.5 mol%) were prepared by using sudden quenching technique and characterized to understand their visible emission characteristic features using spectroscopic techniques such as absorption, excitation and emission. The Judd-Ofelt (J-O) theory has been applied to the absorption spectral features with an aim to evaluate various radiative properties for the prominent fluorescent levels of Pr3+ions in the as-prepared glasses. The emission spectra recorded for the as-prepared glasses under 468 nm excitation show three prominent emission transitions 3P0→3H6, 3P0→3F2 and 3P1→3F4, of which 3P0→3F2 observed in visible red region (648 nm), is relatively more intense. The intensity of 3P0→3F2 emission transition in the titled glasses increases up to 1mol% of Pr3+ ions and beyond concentration quenching is observed. Branching ratios (βR) and emission cross-sections (σse) were estimated for 3P0→3F2 transition to understand the luminescence efficiency in visible red region (648 nm). The CIE chromaticity coordinates were also evaluated in order to understand the suitability of these glasses for visible red luminescence devices. From the emission cross-sections, quantum efficiency and CIE coordinates, it was concluded that 1mol% of Pr3+ ions in ZnPbWTe glasses are quite suitable for preparing visible reddish orange luminescent devices.

The influence of post-preparation annealing atmospheres on the optical properties and energy transfer between Pr3+ and Dy3+ in mixed lanthanum-yttrium oxyorthosilicate hosts

The effect of post-annealing atmospheres (air and Ar-H2) on the optical properties of La2-xYxSiO5 (x = 0, 0.5, 1, 1.5 and 2) co-doped 0.25Pr3+ and 0.25Dy3+ powder phosphors were studied. The X-ray diffraction patterns showed that the as-prepared samples have higher full width at half maximum (FWHM) than the annealed samples. The elemental composition, oxidation states, and chemical and electronic states of the phosphors were determined using the X-ray photoelectron spectroscopy. The band gap values determined from the diffuse reflectance spectra were shown to increase following the post-annealing treatments (with the values increasing in the following manner: Ar-H2-annealed > air-annealed > as-prepared). The photoluminescence intensities of the phosphors also followed the same trend as the band gap values. Two different cases of the photoluminescence mechanisms were proposed for the La2-xYxSiO5:0.25Pr3+,0.25Dy3+ phosphors. Case 1: The 4f5d energy level of Pr3+ lies within the band gap of the host and energy transfer was observed from Pr3+ to Dy3+ via the overlapping 4f5d emission peak of Pr3+ and the 4I15/2 excitation peak of Dy3+. Case II: The 4f5d energy level of Pr3+ lies close or inside the conduction band of the host and the energy transfer was not observed from Pr3+ to Dy3+. The CIE colour coordinates of the phosphors showed tunable emission colours (blue, red and white).

Effects of Sporidiobolus pararoseus Y16 on Postharvest Blue Mold Decay and the Defense Response of Apples

The efficacy of Sporidiobolus pararoseus Y16 in controlling postharvest blue mold caused by Penicillium expansum on apples and the defense response involved were evaluated. The results suggested that the decay incidence of blue mold of apples treated by S. pararoseus Y16 was significantly reduced compared with the control. In vitro testing indicated that germination of spores and germ tube length of P. expansum were markedly inhibited by S. pararoseus Y16. Meanwhile, polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), and catalase (CAT) activities and several pathogenesis-related (PR) gene expression levels (including PR3, PR4, PR5, and PR9) were determined. In apples, the activities of PPO, POD, CAT, and PAL were significantly induced by S. pararoseus Y16 treatment compared with the control fruits. The relative expression levels of PR3 and PR4 were significantly induced at 4 and 6 d, while PR5 was significantly induced at 4 and 6 d and PR9 was significantly induced at 4 d. Therefore, the reduction in apple fruit decay by S. pararoseus Y16 treatment could be related to the increased activities of related enzymes and proteins involved in the defense against pathogens, which suggest that S. pararoseus Y16 is a potential antagonistic yeast.

Insight into Eu redox and Pr3+ 5d emission in KSrPO4 by VRBE scheme construction.

A series of Ln-doped KSrPO4 (Ln = Ce3+, Eu3+, Eu2+, Pr3+) phosphors are prepared through a high-temperature solid-state method. The KSrPO4 compound is confirmed to possess a β-K2SO4 structure with the Pnma group by Rietveld refinement, and the temperature-dependent lattice parameters are investigated with the powder X-ray diffraction results at different temperatures. Ce3+ and Eu3+ ions are introduced to probe the crystal field strength (CFS) and the lanthanide site symmetry by using VUV-UV-vis spectroscopy. The temperature-dependent luminescence properties of KSrPO4: Ce3+/Eu2+ exhibit an excellent thermal stability of Ce3+/Eu2+ luminescence. Based on the VUV-UV-vis spectra of Ce3+ and Eu3+ doped KSrPO4, the vacuum referred binding energy (VRBE) scheme is constructed to understand the redox properties of Eu, the 5d energy levels of Pr3+ and the thermal quenching characteristics of Ce3+ and Eu2+ luminescence.

Transparent oxyfluoride glass-ceramics with NaGdF4 nanocrystals doped with Pr3+ and Pr3+-Yb3+

Transparent oxyfluoride nano-glass-ceramics (GCs) containing NaGdF4 nanocrystals doped with 0.1Pr3+and 0.5Pr3+, and co-doped with 0.5Pr3+-2Yb3+ ions (mol%) were obtained by melting-quenching followed by heat treatments at temperatures near Tg. The addition of rare-earths (RE) ions affects the crystallization kinetics due to the progressive increase of Tg as RE concentration increases. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) show the precipitation of NaGdF4 nanocrystals with sizes between 9 and 30nm. The crystal size increases with the increasing amount of dopant. Energy dispersive X-ray (EDX) analysis confirms the incorporation of the RE ions in the fluoride nanocrystals in the glass-ceramics. This incorporation is also supported by optical characterization. Photoluminescence measurements shows a better resolved structure together with a narrowing of the Pr3+ emission and excitation spectra in the glass–ceramics compared to the precursor glass. The emission spectra and fluorescence decay curves from the 3P0 level of Pr3+ in the codoped samples support the existence of a Pr3+ → Yb3+ energy transfer with slight enhancement of the energy transfer efficiency in the GC sample.

Optical absorption and luminescence properties of Pr3 + ions doped P2O5-PbO-Bi2O3-R2O3 (R = Al, Ga, In) glasses

P2O5-PbO-Bi2O3-R2O3 (R=Al, Ga, In) glasses doped with Pr6O11 were prepared by melt quenching technique. The prepared glasses were characterized by X-ray diffraction, optical absorption, luminescence studies in both visible and near infra-red regions. Judd-Ofelt parameters have been evaluated for three glass systems from optical absorption spectra and in turn radiative parameters for excited luminescent levels of Pr3+ ion are also calculated by using modified J-O theory. J-O intensity parameters follows the trend Ω2>Ω6>Ω4. Transition probability and branching ratio values are observed to high for 3P0→3F2 transition in Pr3+ ion. The calculated laser parameters such as transition probability, scattering emission cross section, optical gain band width are found to high for the glasses mixed with Ga2O3. Two dominant emission bands are observed in the visible region at about 611and 641nm. The evaluated chromaticity coordinates lie in reddish orange region. Quantum efficiency of prepared glasses was measured by using radiative and calculated life times. Near infra-red emission spectra of the prepared glasses exhibit broad emission weak band in the range 1358–1591nm which is suitable for optical telecommunication window devices. Cross relaxation channels are discussed and later verified by Dexter's theory.

Luminescence, scintillation, and energy transfer in SiO2 -Al2 O3 -B2 O3 -Gd2 O3 :Ce3+ ,Pr3+ glasses

Ce3+,Pr3+-codoped SiO2–Al2O3–B2O3–Gd2O3 glasses (SABG:Ce,Pr) were prepared by melt quenching under a CO reducing atmosphere. Luminescence properties were investigated under UV and X-ray excitations. A dominant emission band at 430 nm belonging to the Ce3+:5d1 → 4f transition was observed in the photo- and radio-luminescence spectra. The energy transfer occurs from this Ce3+ band toward the 3PJ levels of Pr3+ with an efficiency of up to 24%, followed by the reduction of integrated luminescence intensity with an increasing Pr3+ concentration. This result is attributed to the increase in the reabsorption of Ce3+ luminescence and the non-radiative energy transfer toward the 3PJ levels of Pr3+. The cross-relaxation process within the Pr3+ pairs can further diminish the total luminescence yield at high Pr3+ concentrations. The integral scintillation efficiency and light yield measurements were carried out and compared to the reference Bi4Ge3O12 (BGO) crystal.

The dynamics of the photoluminescence of Pr3+ in mixed lanthanum yttrium oxyorthosilicate hosts

Praseodymium (Pr3+) doped mixed lanthanum yttrium oxyorthosilicate (LaYSiO5) powder phosphors were synthesized using urea-assisted combustion method. The molar ratio of La:Y were varied in the following manner: La2-xYxSiO5 (x=0, 0.5, 1, 1.5, 2), were x=0 is pure La2SiO5, x=2 is pure Y2SiO5 and x=0.5, 1, and 1.5 are the admixtures of the two compounds. The X-ray diffractometer results showed that the La2SiO5 and Y2SiO5 crystalized in their pure monoclinic phases, while their admixtures are both present in the same phase. The Burstein–Moss (BM) shift was used to explain the increase observed in the band gap after doping. The influence of the host crystal field on the branching ratios of the photoluminescence emission intensities of the 3P0 and 1D2 energy levels of Pr3+ were studied. The electronic transition from the 3P0 transition dominated the emission spectra when x=0, while the 1D2 electronic transition dominated when x=2. The variation in the branching ratios of the 3P0 and 1D2 emission with the change in the molar ratio of La:Y could be due to 3P0→1D2 non-radiative transitions, which increased with the crystal field of the host as the value of x increased (i.e., as the molar ratio of Y increases). Furthermore, it was shown that the 3P0 emission lines emerged from Pr3+ ions occupying La1 and Y1 sites of La2SiO5 and Y2SiO5 respectively, while the 1D2 emission lines emerged from Pr3+ ions occupying La2 and Y2 sites. The decay curve showed three lifetime components from both 3P0 and 1D2 emission lines, with the 1D2 lines having higher lifetimes in all cases.

Effect of Pr3+ ions concentration on the spectroscopic properties of Zinc telluro-fluoroborate glasses for laser and optical amplifier applications

A new series of Pr3+ ions doped Zinc telluro-fluoroborate (PrZTFB) glasses have been prepared by adding up to 2wt% Pr2O3. Spectroscopic properties were explored through X-ray diffraction, Raman, optical absorption, photoluminescence and decay measurements. The Raman spectra reveal the presence of different vibrational bonds of the borate and tellurite network(s). The bonding parameters have shown the ionic nature of the bonding Pr–X (X=O,F). The optical band gap energy and Urbach energy have been determined to understand the electronic band structure. The Judd-Ofelt parameters Ωλ (λ=2, 4 and 6) have been calculated to explore the bonding environment around the Pr3+ ions. The luminescence spectra exhibit emission bands in the visible region attributed to the 3P0→3H4, 3F2, 3F3, 3F4 and 3P1→3H5 and 1D2→3H4, 3H5 transitions and a broad near infrared emission band at around 1330nm corresponding to the 1G4→3H5 transition with a FWHM ≈70nm. The glasses lying in the reddish orange region of CIE 1931 chromaticity diagram have been found suitable for light emitting diode applications. The decay curves of 3P0 and 1D2 levels of Pr3+ exhibit non exponential behavior for all the glasses and experimental lifetime value is found to decrease while increasing the Pr3+ ions due to cross-relaxation mechanisms. The radiative parameters corresponding to the prominent 3P0→3H4, 1D2→3H4 and 1G4→3H5 emission transitions have been determined to elucidate the suitability of the studied glasses for the fabrication of photonic devices that includes laser materials and broad band optical amplifiers.

Influence of Bi3+ ions on the amplification of 1.3 μm emission of Pr3+ ions in lead silicate glasses for the applications in second telecom window communications

The primary objective of this study is to characterize 1G4 → 3H5 (1.3μm, which is highly important in telecommunications) and also 3P0 → 3F2 (red emission) spectral lines of Pr3+ ions in lead silicate glasses sensitized with bismuth ions. The intensity of these spectral lines exhibited large amplification (nearly four times) due to co-doping with Bi3+ ions with fixed concentration of Pr3+ ions. Several radiative parameters, e.g., transition probabilities (Aij), branching ratios (β), radiative life times (τ) and quantum efficiencies (η) of these spectral lines were evaluated using modified Judd-Ofelt theory. These parameters exhibited the maximal values when the glasses were codoped with the optimal concentration of Bi2O3 (5.0mol%). The increasing population of 3P0 and 1G4 levels of Pr3+ ions (with the gradual increase of Bi2O3 concentration up to 5.0mol%) that caused the amplification of above mentioned emissions occurred: (i) due to the energy transfer from 3P1→1S0 emission transition of Bi3+ ions and (ii) due to the increasing presence of Bi3+ ions in octahedral positions that are predicted to induce structural defects in the glass network. The quantitative analysis of these results together with the kinetic rate equations suggested that the Pr3+ ions doped lead silicate glasses mixed with (about 5.0mol%) Bi2O3 are highly efficient in producing intense 1.3μm (1G4 → 3H5) narrow emission. Hence, it is concluded that the optical fibers drawn from the glasses of such compositions are highly useful for the applications in the second telecom window.

Photoluminescence properties of Pr3+ doped Bi2ZnOB2O6 microcrystals and PMMA-based composites

Photoluminescence properties of red-emitting Pr3+-doped Bi2ZnOB2O6 microcrystalline powder and PMMA-based composite materials were reported. Bi2ZnOB2O6:Pr3+ powders were synthesized by means of the modified Pechini method. The morphology and crystallographic structure of Bi2ZnOB2O6:Pr3+ microcrystals were investigated by XRD and HRTEM. The PMMA-based composite materials were prepared by embedding of Bi2ZnOB2O6:Pr3+ powder in the PMMA matrix. The vibrational properties of the powder and composite systems were investigated by μ-Raman spectroscopy. Emission spectra of the samples were measured under blue (451.6 nm) and UV (320 nm) excitation. Both, the powder and composite samples show enhancement of red emission (1D2 → 3H4) and quenching of greenish-blue luminescence from 3P0 level of Pr3+ ions after excitation in UV and VIS caused by the 3P0 ∼ 1D2 non-radiative relaxation of Pr3+ ion by low-lying charge transfer state and non-radiative de-excitation through Pr3+–Bi3+ energy transfer. The response of the powder and composite samples to pulsed excitation at 451.6 nm was measured by monitoring emission from the 1D2 level (595 nm/3P0 → 3H6 transition). The determined lifetimes τ1 and τ2 of the red emission at 595 nm (1D2 → 3H4 transition) of the composite are significantly longer in comparison to powder samples. Moreover, because of the good nonlinear optical properties of the Bi2ZnOB2O6 crystals and effective luminescence of the Pr3+-doped Bi2ZnOB2O6 powders and composites, they can be very useful as bi-functional materials in the new generation of optoelectronic devices.

Emission characteristics of Pr-doped Ga2S3–GeS2–CsX (X=Cl and Br) glasses in the visible region

Since Pr3+ ion has various emission bands in the visible region, Pr3+-doped materials are expected to be a potential candidate as laser media. In the present study, sulfide halide glasses based on Ga2S3–GeS2–CsX (X=Cl, Br), containing 20mol% or more of CsX, and doped with Pr3+, were prepared for investigation of the visible spectroscopic properties of these glasses. The absorption edges were located around 460nm and various emission bands in the visible region were observed with 450nm excitation. Judd–Ofelt analyses were performed and total radiative transition rates from the 3Pj levels of Pr3+ were estimated. The lifetime of the decay was approximately 10μs for the emission at 654nm due to the 3P0→3F2 transition. The emission quantum efficiencies were estimated from the ratio of the emission lifetime to the radiative transition lifetime calculated with the Judd–Ofelt analyses. The large efficiencies were attributed to the low phonon energies of the glass matrices compared with the energy gap between the 3P0 and the next lower level.

Multichannel emission from Pr3+ doped heavy-metal oxide glass B2O3–PbO–GeO2–Bi2O3 for broadband signal amplification

Pr2O3 doped 26.66B2O3–52.33PbO–16GeO2–4Bi2O3–1Pr2O3 (BPGBPr) glass was synthesized by melt quenching technique. X-ray diffraction confirmed the amorphous nature of the glass and the presence of different vibrational groups was identified by Raman spectroscopy. Differential thermal analysis indicated that the glass transition and crystallization temperature were ~354°C and ~521°C respectively, indicating good thermal stability. Visible and near infrared absorption spectra were measured and used to evaluate the Judd-Ofelt intensity parameters to calculate the radiative properties for the emission levels of Pr3+. Photoluminescence spectra were recorded in the visible and infrared regions at temperatures between 16 and 300K. The spectroscopic results indicated that BPGBPr can be useful as a material for broadband optical amplifier in the region of ~1450cm−1.

Optical properties and spectroscopic study of different modifier based Pr3 +:LiFB glasses as optical amplifiers

In this paper, we report the preparation and optical characterization of Pr3+ doped lithium fluoro borate (LiFB) glasses for six different chemical compositions of Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. The structural and optical properties of these glasses were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption and photoluminescence techniques. The optical absorption spectra of Pr3+ ions in LiFB glasses have been recorded in the UV–VIS-NIR region. The optical absorption data are used to calculate various spectroscopic parameters such as Racah (E1, E2, E3) and spin-orbit interaction (ξ4f) parameters. Judd-Ofelt (J-O) (Ωλ where λ=2, 4 and 6) intensity parameters were determined by applying J-O theory, which in turn used to calculate the radiative properties such as radiative transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βr) for all emission levels of Pr3+ ion in different LiFB glass matrices. By using the J-O theory and luminescence parameters, stimulated emission cross sections (σp) of prominent transitions, 3P0→3H4 and 1D2→3H4 of Pr3+ ion in all LiFB glasses were calculated. 3P0→3H4 possesses higher branching ratios and stimulated emission cross-sections for the Pr3+:LiFB(Mg-Ca) glass, which can be used as a best laser excitation. The optical gain parameter (σpxτR) was noticed higher in Pr3+:LiFB(Mg-Ca) and Pr3+:LiFB(Cd-Pb) glasses for the transition 3P0→3H4 transition, and these glasses have potential for optical amplification at 488 nm wavelength.

Growth and spectral properties of Pr3+-doped Y3Al5O12 crystal for potential use in all-solidstate visible laser

Pr3+-doped Y3Al5O12 (Pr:YAG) single crystal has been grown by the Czochralski technique. The room temperature absorption spectrum, emission spectrum, and fluorescence decay curves of Pr:YAG single crystal were studied systematically. Strong absorption peaks in the blue region corresponding to 3H4→3P2,1,0 + 1I6 transitions and emission peaks in the visible region originating from the 3P1, 3P0 and 1D2 levels of Pr3+ are observed. The emission cross-sections of four main promising laser transitions at 488, 566, 611 and 638 nm were estimated separately. Results show that Pr:YAG single crystal is an excellent candidate for all-solid-state visible laser material that can be pumped by blue laser diode.

Schottky contribution to the heat capacity of monazite type (La, Pr)PO4 from low temperature calorimetry and fluorescence measurements

We show that the combination of fluorescence spectroscopy and low temperature heat capacity measurements of Pr-containing samples in the (La,Pr)PO4 solid solution series can be employed to strongly constrain the Stark energy levels of Pr3+ in monazite type structures. The resulting set of Stark energy levels for the 3H4 ground state of Pr3+ reproduces the low temperature Schottky anomaly of the heat capacity much more accurately than theoretical models published earlier. We also show that there is no excess heat capacity along the binary solid solution with respect to an interpolation between the two end members LaPO4 and PrPO4.

Near-Infrared Quantum Cutting Long Persistent Luminescence.

By combining the unique features of the quantum cutting luminescence and long persistent luminescence, we design a new concept called “near-infrared quantum cutting long persistent luminescence (NQPL)”, which makes it possible for us to obtain highly efficient (>100%) near-infrared long persistent luminescence in theory. Guided by the NQPL concept, we fabricate the first NQPL phosphor Ca2Ga2GeO7:Pr3+,Yb3+. It reveals that both the two-step energy transfer of model (I) and the one-step energy transfer of model (IV) occur in 3P0 levels of Pr3+. Although the actual efficiency is not sufficient for the practical application at this primitive stage, this discovery and the associated materials are still expected to have important implications for several fields such as crystalline Si solar cells and bio-medical imaging.

Influence of multiphonon and cross relaxations on 3P0 and 1D2 emission levels of Pr3+ doped borosilicate glasses for broad band signal amplification

We discuss non-radiative relaxations of visible–near infrared (Vis–NIR) emissions originating from 3P0 and 1D2 levels of Pr3+ glasses. Thermal stability of host lithium aluminium borosilicate (LABS) glass is estimated from thermogravimetric and differential thermal analysis. The structural analysis of host LABS glass through Fourier transform infrared and Raman spectral profiles provide an insight to understand the effect of OH content and phonon energy on luminescence characteristics of Pr3+ ions. Visible emission spectrum of Pr3+ glass is composed of two prominent emission bands at 493 nm (3P0 → 3H4) and 605 nm (1D2 → 3H4) when excited by 448 nm. In NIR region a narrow emission band at 1.06 μm (1D2 → 3F3) and ultra-broad emission band at 1.49 μm (1D2 → 1G4) are observed for 488 nm excitation. For these emission transitions, emission decay curves are measured and analysed. The lifetime shortening due to non-radiative energy transfer is explained by multiphonon interactions and cross-relaxation routes, and later verified by Dexter's model. Electric dipole–dipole mechanism is identified to be responsible for ion–ion interactions intervening in 3P0 and 1D2 states of Pr3+ causing quenching in emission intensities and lifetimes. The large absorption and stimulated emission cross-sections of Pr3+ ions around 1.49 μm suggests suitability of a host material operating for broadband signal amplifications at low-loss optical telecommunication windows. Besides, emission parameters like stimulated emission cross-section (σemi), effective band width (Δλeff) are calculated for 1.49 μm (1D2 → 1G4) of Pr3+ doped silicate based glasses.

First observation of optical gain on 5d–4f transitions of Ce3+ ions in up-conversionally pumped Ce3+, Pr3+:LiY0.3Lu0.7F4 mixed crystals

The results of pump–probe experiments on the 5d–4f transitions of Ce3+ ions in up-conversionally pumped Ce3+, Pr3+:LiY0.3Lu0.7F4 crystals are presented and differential gain in the ultraviolet spectral range is demonstrated for the first time. The key parameters for the processes providing up-conversion pumping of the 5d states of Ce3+ ions in Ce3+, Pr3+:LiY0.3Lu0.7F4 mixed crystals via the 1D2 level of Pr3+ ions are estimated for the first time and the optimal pumping conditions are determined. The results of the pump–probe experiments and the mathematical modeling demonstrate that there are good prospects for the use of LiY0.3Lu0.7F4:Ce3+, Pr3+ crystals as an active medium of solid-state tunable UV lasers with up-conversion pumping.