Optical Properties Of Nd3 Research Articles

Near-infrared luminescence of Nd^3+ and Tm^3+ ions doped ZnO nanocrystals

Intense near-infrared luminescence of Nd(3+) and Tm(3+) ions in the region of 860-1550 nm were achieved in 10-15 nm wurtzite ZnO nanocrystals fabricated by a facile sol-gel process. The optical properties of Nd(3+) and Tm(3+) ions were investigated by using the steady-state and time-resolved laser spectroscopy. Due to the well-ordered crystal-field surroundings experienced by Nd(3+) and Tm(3+) ions, sharp and well resolved emission lines of Nd(3+) and Tm(3+) ions were identified at 4-300 K. Time-resolved luminescence and decay behaviors of the (4)F(3/2)-->(4)I(11/2) transition of Nd(3+) ions reveal the existence of multiple Nd(3+) sites in ZnO nanocrystals.

PREPARATION OF Nd – FLUORIDE LASER GLASS AND INVESTIGATION OF ITS CHARACTERISTICS

Fluorophosphate neodymium laser glass has been prepared by discontinuous melting technique.Special melting and casting conditions were followed to prevent devitrification of glass samples.Furnace melting followed by slow cooling resulted formation of non vitreous glass. Problems ofhigh viscosity melt and incomplete solubility and immiscibility of glass components wereencountered by adjusting composition of glass components. X-ray diffraction analysis of theprepared glass samples proved the formation of amorphous phase. The prepared Nd – fluoride glasshas low refractive index which is an important parameter for high power laser application. Opticalproperties of Nd – fluoride glass samples were investigated. UV – visible spectra showed almosttotal absorbance of light at wave length below 400 nm, while in the visible range a typical spectrumof Nd3+ ions covers the entire range. Infra – red spectral properties of these samples were studied.Transmission of the glass was found to be dependent on neodymium concentration.

Synthesis and optical properties of KZnLa 0.99Nd 0.01(VO 4) 2 triple vanadate(V)—New promising laser materials

In an attempt to find a neodymium–vanadate system with long lifetime of 4F 3/2 level and relatively strong 4F 3/2→ 4I 11/2 emission for laser applications, the optical properties of Nd 3+ in a new KZnLa(VO 4) 2 host is reported. The crystalline samples were obtained at 900 °C in air. The samples were crystallized in monoclinic system and were isostructural with KZnLa(PO 4) 2. KZnLa 0.99Nd 0.01(VO 4) 2 strongly emits in the near infrared range with the maxima at 871.6 and 1057 nm upon excitation through the 4F 5/2 level (808 nm) or by the charge transfer bands of VO 4 3−. The lifetime of 4F 3/2 level of Nd 3+ ion is larger than that observed in other neodymium–vanadates systems.

Optical Properties of Micro-Pulling Down Method Grown Nd3+:(La1-x,Bax)F3-x as Potential Vacuum Ultraviolet Laser Material and Scintillator

The optical properties of Nd3+:LaF3 and Nd3+:(La1-x,Bax)F3-x (x=0.1) crystals, which were efficiently grown by the micro-pulling down method, were investigated using a vacuum ultraviolet spectrum-resolved streak camera system. The fluorescence of the Nd3+:LaF3 crystal is centered at 174 nm with a full width at half maximum of 8 nm and a lifetime of 8.9 ns. On the other hand, the fluorescence of the Nd3+:(La1-x,Bax)F3-x (x=0.1) crystal is centered at 180 nm with a full width at half maximum of 12 nm and a lifetime of 6.1 ns. Since the (La1-x,Bax)F3-x (x=0.1) host is transparent in the vacuum ultraviolet region having a transmission edge at 160 nm, it is proposed that Nd3+:(La1-x,Bax)F3-x (x=0.1) is suitable as a vacuum ultraviolet scintillator and as a potential laser material.

Optical properties of Nd(TTA)3(TPPO)2 doped polymer and its potential laser application

In this work, the Nd(III) complex doped PMMA with high stimulated emission cross-section, which is one of the most important parameters for laser design, was presented. The molecular structure of the complex, Nd(TTA)3(TPPO)2 (HTTA: 2-thenoyltrifluoroacetone, TPPO: triphenylphosphine oxide), was characterized by single-crystal X-ray diffraction. From the absorption and luminescence spectra, the Judd–Ofelt parameters (Ω2, Ω4 and Ω6) of the Nd3+ ion in PMMA were obtained and the radiative properties were discussed using Judd–Ofelt theory. The stimulated emission cross-section of the emission band at 1.060μm is 2.75×10−20cm2, which is higher than that of other Nd(III) complex doped organic systems and even comparable with some laser glasses. On the basis of the experimental data and Judd–Ofelt analysis, the 4F3/2→4I11/2 transition of the Nd3+ ion in PMMA can be considered as a possible laser transition.

Spectroscopy and frequency upconversion inNd3+-dopedTeO2–TiO2–Nb2O5 glass

In this work, we report the optical properties ofNd3+ ions in telluriteglasses (TeO2–TiO2–Nb2O5) fortwo different Nd3+ concentrations. Judd–Ofelt intensity parameters were derived from the absorptionspectrum and used to calculate the radiative lifetime and stimulated emissioncross section of the transition. The non-exponential character of the decays from the4F3/2 level and the reduction of the lifetime even at low temperature asNd3+ concentration increases reveal the presence of nonradiative processes. The time evolution of the decaysfrom the 4F3/2 level is consistent with a dipole–dipole direct energy transfer mechanism. Upconversionprocesses that produce green, orange, and red emissions after infrared excitation in the4F3/2 and 4F5/2 levels have been investigated by using steady-state and time-resolved laser spectroscopy.The characteristics of the excitation spectra together with the temporal behaviour of thedecays from the upconverted luminescence suggest that energy transfer upconversionprocesses are the dominant mechanisms in such emissions.

Structural and optical properties of Nd- and Tb-doped BaY2F8

In the present work, we report the optical properties of rare-earth doped BaY2F8 and its potential use as a scintillator in radiation detection. The samples were synthesized and grown by the zone melting method under a HF flow. X-ray powder diffraction was performed and quantitative phase analysis was done using the Rietveld method. Emission and excitation spectra of the doped samples were measured at room temperature. The identification of the transitions was done comparing the excitation and emission peaks with the results obtained from computer modelling. The scintillator properties of the pure and doped samples were checked by measuring the radioluminescence of the sample when excited with different types of radiation, revealing that these materials are promising radiation detectors.

High-pressure luminescence in Nd3+-doped MgO:LiNbO3

Optical properties of Nd3+-doped MgO:LiNbO3 have been intensively studied during the last years because of its potential applications as a multifunctional non-linear laser system capable, for example, of multi-frequency laser light generation. In order to exploit fully the advantages of this system, a complete knowledge of its excited state dynamics is required. The application of high-hydrostatic pressure is a powerful technique to study the influence of the changing strength of the crystal field on the spectroscopic properties of luminescent centers in crystals. We have studied the dependence of the emission bands and the lifetimes of the metastable 4F3/2 state of Nd3+ on hydrostatic pressure.

Influence of defects in the output power of c- and a-axis growth Nd:YVO4 single laser crystals

The differences in the output powers of a- and c-axis growth neodymium-doped yttrium orthovanadate (Nd:YVO4) crystals grown by the Czochralski method were investigated. It was found that the differences in the output powers are due to crystal defects, such as veils and grain boundaries, which lead to changes in the thermal and optical properties of Nd:YVO4 and reduce the quality of the laser beam. To relieve internal stresses introduced by the crystal growth process, boules form grain boundaries and other thermodynamically favorable defects in the boule. Because c-axis grown Nd:YVO4 crystals do not contain a slip system, no grain boundaries or ghost veils can form. As a result, c-axis grown boules are highly vulnerable to thermal and stress fractures and require careful growth parameter selection to overcome these defects. However, a-axis grown crystal contain a slip system and can form thermodynamically stable defects including grain boundaries, scatter centers, and ghost veils. In this paper, data are presented showing that properly grown c-axis growth crystal, having no grain boundaries or veils, is more suited for high output power applications than a-axis grown one.

Optical Properties of Nd3+ in Nd(DBM)3Phen-doped Poly(methyl methacrylate)

Nd(DBM)3Phen-doped (DBM is dibenzoylmethane and Phen is phenanthroline) polymethyl methacrylate (PMMA) is prepared. Optical absorption, excitation and emission spectra were analyzed for Nd3+ in Nd(DBM)3Phen-doped PMMA. Using the Judd-Ofelt theory, the absorption spectrum was analyzed. The Judd-Ofelt(J-O) intensity parameters of Nd(DBM)3Phen-doped polymethyl methacrylate were calculated to be 2 = 20.971020 cm2, 4 = 3.421020 cm2, 6 = 2.901020 cm2. The radiative lifetime (631 s) of the excited 4F3/2 level is given. The stimulated emission cross-sections and the fluorescence branch ratios for the 4F3/2 4IJ' transitions are also evaluated. Analysis reveals that Nd(DBM)3Phen-doped PMMA is promising for application in polymer optical fibers and planar waveguides.

Luminescence and optical absorption properties ofNd3+ ions in K–Mg–Al phosphate and fluorophosphate glasses

Absorption and emission properties and fluorescence lifetimes for the transition of Nd3+ ions embedded in P2O5–K2O–MgO–Al2O3 (PKMA)-basedglasses modified with AlF3 and BaF2 are reported at room temperature. The observed energy levels ofNd3+ ions in these glasses have been analysed through a semi-empirical free-ion Hamiltonianmodel. The spin–orbit interaction and net electrostatic interaction experienced by theNd3+ ions followthe trend as PKMA>PKMA+AlF3>PKMA+BaF2 glasses. Judd–Ofelt analysis has been carried out on the absorption spectra of 1.0 mol%Nd3+-doped glasses to predict the radiative properties for the fluorescent levels of theNd3+ ion. Branching ratios and stimulated emission cross-sections show that the transition of the glasses under investigation has the potential for laser applications. TheInokuti–Hirayama model has been applied to investigate the non-radiative relaxation of theNd3+ ion emittingstate, 4F3/2. Based on the decay curve analysis, concentration quenching of the4F3/2 emission has been attributed to a cross-relaxation process between theNd3+ ions.

Optical and luminescence properties ofNd3+ ions in K–Ba–Al-phosphate and fluorophosphate glasses

Phosphate (PKBAN: P2O5+K2O +BaO +Al2O3+Nd2O3) andfluorophosphate (PKBFAN: P2O5+K2O +BaO +BaF2+Al2O3+Nd2O3 and PKBAFN: P2O5+K2O +BaO +Al2O3+AlF3+Nd2O3) glasses were prepared with three concentrations (0.1, 1.0 and 2.0 mol%) ofNd3+ ionsand their detailed luminescence properties have been investigated. Absorption spectra for 1.0 mol%of Nd3+-doped glasses have been analysed using Judd–Ofelt (JO) theory. The observed bands inabsorption spectra from ground to excited states are assigned and analysed with theparameterized free-ion Hamiltonian model. The JO parameters have been used topredict radiative properties for (J = 15/2, 13/2,11/2 and9/2) transitionsof Nd3+ ions in these glasses. The Inokuti–Hirayama model has been applied to the non-exponentialbehaviour of the decay profiles to investigate the mechanism involved in the energy transferbetween the donors and acceptors.

Thermal and optical properties of Nd3+:SrWO4: a potential candidate for eye-safe 1.517 μm Raman lasers

Nd3+ doped SrWO4 single crystal with a dimension of ϕ 30 mm×80 mm and a good optical quality was grown by Czochralski method. The refractive indices in a function of wavelength and the principal coefficient of thermal expansion were precisely measured. The three principal coefficients of thermal expansion along (001), (010), (100) are 2.39×10-5 °C-1, 1.09×10-5 °C-1, and 0.97×10-5 °C-1, respectively. In the framework of the Judd–Ofelt theory, the intensity parameters, radiative probabilities, radiative branching ratios and radiative lifetime were calculated. We also present end-pumped self-stimulated Raman scattering in the two laser channels 4F3/2→4I11/2 and 4F3/2→4I13/2 to generate 1.18 and 1.52 μm Self-stimulated Raman scattering radiations, the latter being close to the eye-safe domain. This material is a potential material for eye-safe Raman lasers.

Structural and optical properties of Nd:LuVO 4 waveguides grown on sapphire substrates by pulsed laser deposition

High-quality Nd-doped lutecium vanadate thin films on sapphire substrates have been deposited by pulsed laser deposition (KrF excimer laser). The substrate temperature during the deposition was in the range 600–700 °C under different oxygen pressure between 2 and 20 Pa. The quality of films and crystallographic relationships were assessed by X-ray diffraction, atomic force microscopy (AFM), and prism-coupling measurements. The refractive indices of the films have been inferred from dark-mode prism coupling measurements and are slightly smaller than that of the bulk crystal.

Purification, material synthesis, and infrared emission from Nd doped PbBr2 and PbI2

ABSTRACTWe report on the material synthesis and infrared optical properties of Nd doped lead bromide (PbBr2) and lead iodide (PbI2) bulk crystals. Commercial PbBr2 and PbI2 materials were purified through repeated solidification and horizontal zone refinement. After purification, Nd doped lead halides were synthesized and grown by Bridgman technique. Under optical excitation, Nd:PbBr2 samples exhibited several near-infrared emission bands centered at 816 nm, 891 nm, 963 nm, 1069 nm, 1183 nm, 1356 nm, and 1535 nm. The emission from Nd:PbI2 samples was similar to that of from Nd:PbBr2, but slightly shifted to longer wavelengths. The observation of 1540 nm emission from Nd3+ ions is unusual and reflects on the small non-radiative decay rates in the investigated halides. Lead halides have low maximum phonon energies, which reduces non-radiative decay due to multi-phonon relaxations. In contrast to Nd:YAG, Nd:PbBr2 and Nd:PbI2 exhibited efficient emission from the 4F5/2, 2H9/2 excited states, which are located only ∼1000cm−1 above the 4F3/2 level of Nd3+. Under 808 nm diode pumping, both samples also exhibited broad mid-infrared emission bands centered at ∼5.1 μm.

Optical properties of Nd^3+- and Tb^3+-doped KPb_2Br_5 and RbPb_2Br_5 with low nonradiative decay

We report on the optical properties of Nd3+- and Tb3+-doped low-phonon-energy moisture-resistant host crystals, potassium lead bromide (KPb2Br5), and rubidium lead bromide (RbPb2Br5), including absorption, emission, and emission lifetime measurements as well as calculations of the multiphonon decay rate, Judd–Ofelt parameters, and radiative transition probabilities for relevant (laser) transitions in these crystals. The RE3+:MPb2Br5 (M=Rb, K) crystal is a promising candidate for long-wavelength infrared applications because of the low phonon frequencies and other favorable features.

Optical properties of Nd(DBM) 3Phen in MMA and PMMA

The absorption spectra of Nd(DBM) 3Phen in MMA solution and PMMA matrix were measured at room temperature within wavelength range of 470–950 nm. From the data available in the absorption spectra, spectroscopic parameters such as Slater–Condon parameters ( F 2, F 4, F 6), Lander parameter ( ζ 4f), nephelauxetic effect parameters ( β, b 1/2, δ) and Judd–Ofelt parameters ( Ω 2 , Ω 4 , Ω 6 ) were derived. The relationship between the structure of rare-earth complexes and the nephelauxetic effect, Judd–Ofelt parameter Ω 2 was analyzed. The close δ values, oscillator strengths of the hypersensitive transition and nearly similar Ω 2 values of Nd(DBM) 3Phen in MMA and PMMA indicate that the structure in the vicinity of Nd 3+ are very similar. The radiative properties of Nd(DBM) 3Phen doped PMMA were predicted with the help of the Judd–Ofelt analysis. The values of the radiative lifetime and the emission cross section of 4F 3/2 → 4I 11/2 fluorescence transition are comparable with those shown by glasses being used in the solid state laser applications.

Spectroscopic Studies and Crystal Field Calculation for Nd3+ in Single Crystal K2YF5.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Spectroscopic studies and crystal field calculation for Nd 3+ in single crystal K 2YF 5

Optical properties of Nd 3+ doped into K 2YF 5 single crystal have been analysed. A detailed electronic energy level scheme of Nd 3+ ion in the crystalline structure has been deduced from the absorption, emission and time resolved spectra recorded at 12 K. Energy level simulation of Nd 3+ ions in K 2YF 5 has been carried out and the phenomenological crystal field parameters were determined. The root mean square (r.m.s.) standard deviation is 19.0 cm −1, indicating a satisfying agreement between the calculated and experimental levels. The results are also compared to those reported for BaY 2F 8:Nd 3+ and LiYF 4:Nd 3+ crystals, and the tendency of a covalence and crystal field decreasing effect was observed from K 2YF 5, BaY 2F 8 to LiYF 4.

Optical properties of Nd3+-doped Ca3(VO4)2 single crystal fiber

Abstract Optical absorption and photoluminescence of Ca 3 (VO 4 ) 2 single crystal grown by a floating-zone technique and containing Nd 3+ ions were investigated. High absorption coefficients and broadening of most absorption bands are present at 300 K, while substructures in some of the same bands can be evidenced at 12 K. Most features of measured spectra are characteristic of random occupation of more than a single Ca 2+ site by the Nd 3+ ion and of distortions provoked by different charge compensation mechanisms involving oxygen vacancies promotion in the crystal lattice. Nd 3+ optical properties were studied by using the Judd-Ofelt theory to calculate the spectral parameters relevant for laser applications.