Transitions Of Nd3 Research Articles

Efficient intracavity frequency-doubled Nd:GdVO4-LBO red laser at 670.5 nm under direct 888 nm pumping

We report an efficient laser emission on the 1341 nm 4F3/2 to 4I13/2 transition in Nd:GdVO4 under the pump with diode lasers at 888 nm. Continuous wave (CW) 6.58 W output power at 1341 nm is obtained under 18.3 W of incident pump power; the slope efficiency with respect to the incident pump power was 45.1%. Moreover, intracavity frequency doubling with LiB3O5 (LBO) nonlinear crystal yielded 1.77 W of red light at 670.5 nm.

Efficiency intracavity frequency-doubled Nd:CNGG-LBO green laser at 530.5 nm under direct 885 nm pumping into the emitting level

We report an efficient laser emission on the 1061 nm 4 F 3/2 to 4 I 11/2 transition in Nd:CNGG under the pump with diode laser at 885 nm. Continuous wave (CW) 5.4 W output power at 1061 nm is obtained under 17.4 W of incident pump power; the slope efficiency with respect to the incident pump power was 36.2%. Moreover, intracavity frequency doubling with LiB3O5 (LBO) nonlinear crystal yielded 1.75 W of green light at 530.5 nm. An optical-to-optical efficiency with respect to the incident pump power was 10.1%.

Variation of the stimulated emission cross section in Nd:YAG caused by the structural changes of Russell-Saunders manifolds

It was experimentally found that electronic structures of Russell-Saunders manifolds in Nd:YAG depended on the Nd3+-doping concentration (CNd) and its fabrication process. Both of the bandwidth and the branching ratio in fluorescent transitions in Nd:YAG varied almost linearly depending on CNd, and a fabrication process has its own diluted limit of the bandwidth and the branching ratio. Also dependences of Stark splitting in Nd:YAG were also observed. Nd3+-doping causes 1.9% and 4.5% reduction in the stimulated emission cross section of Nd:YAG per 1at.% of CNd at 1.064 μm and 1.319 μm, respectively.

Tunable continuous-wave laser at quasi-three-level with a disordered Nd:LGS crystal

A diode-pumped tunable CW Nd(3+):LGS laser at quasi-three-level has been demonstrated. The output power up to 403 mW at the central wavelength of 904 nm was obtained, corresponding to a slope efficiency of 29.7%. Taking advantage of the broad emission spectrum of the disordered crystal Nd:LGS, we tuned the laser wavelength within the spectral range of 899.8 to 906.6 nm with an etalon inserted into the V-type cavity. To the best of our knowledge, it is the first time to obtain a tunable laser based on the (4)F(3/2)-(4)I(9/2) transition of Nd(3+)-doped crystals.

Atomistic mechanism of cyclic phase transitions in Nd–Fe–B based intermetallics

Mechanical milling induced atomic disorder and the mechanism of the cyclic crystal → amorphous → crystal phase transitions in a Nd 2Fe 14B intermetallic – based Nd 10Fe 85B 5 alloy were investigated. Least square first shell fitting of Extended X-ray Absorption Fine-Structure (EXAFS) data of mechanically milled samples revealed that phase evolution during mechanical milling of Nd 10Fe 85B 5 alloy occurred in two stages as a result of two dynamical effects: milling induced forced atomic mixing and enhanced diffusion due to continuous production of point defects. In the first stage of milling, atomic mixing of Nd and Fe atoms dominated, resulting in extensive chemical and structural disorder in the initially ordered intermetallic, followed by amorphization. The second stage of milling was characterized by a remarkable increase in point defect density. Enhanced diffusion resulted in redistribution of alloy atoms and annihilation of these point defects leading to the precipitation of α-Fe nanocrystals in the amorphous matrix. Thus the time evolution of defect structures formed during mechanical milling and their atomic scale interactions led to the cyclic phase transitions in the Nd 10Fe 85B 5 alloy. These milling induced changes in atomic order were found to strongly influence magnetic properties. Crystallization of mechanically milled alloy and effect of annealing parameters on magnetic properties was also analyzed.

Electrochemical and spectrophotometric study on trivalent neodymium ion in molten binary mixtures of LiCl and alkali earth chlorides

The thermodynamic stability of Nd(III) complexes was studied by electrochemical techniques for molten binary mixtures composed of LiCl and an alkali earth chloride, CaCl 2, SrCl 2, or BaCl 2 at 923 K. The Gibbs free energy change of formation of Nd(III) in the melts was determined. The obtained values showed a good correlation with the polarizing power of solvent cations. The Nd(III) complex was more stable in the melts with low polarizing power. The electronic absorption spectrum of the hypersensitive f– f transition of Nd 3+ was investigated to obtain information about the structural change of the NdCl 6 3 - complex. The estimated oscillator strength of the 4 G 5/2, 2 G 7/2 ← 4 I 9/2 transition and the degree of the energy splitting in electronic energy levels showed different trends upon the polarizing power for each of added alkali earth chloride. This indicates that the coordination environments further from second neighbors could have significant impact on the electronic energy levels of Nd(III) in the mixtures including alkali earth cations.

Quasi-three level laser based on diode-pumped Nd3+:YAlO3 crystal

We describe the output performances of the 930 nm 4 F 3/2 → 4 I 9/2 transition in Nd3+:YAlO3 (Nd:YAP) under in-band pumping with diode laser at the 803 nm wavelength. An end-pumped Nd:YAP crystal yielded 1.13 W of continuous-wave (CW) output power for 17.8 W of incident pump power. Moreover, intracavity second-harmonic generation has also been achieved with a power of 172 mW at 465 nm by using a LiB3O5 (LBO) nonlinear crystal. The blue beam quality factor M 2 was less than 1.3. The blue power stability was less 3% in 60 min.

Crystal growth and optical properties of the Nd 3+ doped LuF 3 single crystals

Thirty millimeter diameter single crystal of Nd 3+ doped LuF 3 was grown using LiF as solvent. The single phase crystallization was confirmed by the powder X-ray diffraction, and high structural perfection was demonstrated by X-ray rocking curve (XRC) measurements. FWHM of XRC for 220 reflection was 32 arcsec. No remarkable absorption due to unfavorable impurities was observed from optical absorption measurements in the VUV spectral region. The crystal showed the VUV luminescence peaking around 178 nm that is consistent with the 4f 25d–4f 3 transition of Nd 3+ ion. The luminescence intensity of Nd:LuF 3 under X-ray irradiation was significantly higher than that of reported VUV scintillators such as Nd:LaF 3 or Nd:LiLuF 4.

Diode-pumped quasi-three-level Nd:CLNGG laser at 928 nm

We describe the output performances of the 928 nm 4 F 3/2 → 4 I 9/2 transition in Nd:CLNGG under diode-laser pumping. An end-pumped Nd:CLNGG crystal yielded 1.3 W of continuous-wave output power for 17.8 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 11.2%. Furthermore, with 17.8 W of diode pump power and the frequency-doubling crystal LiB3O5 (LBO), a maximum output power of 260 mW in the blue spectral range at 464 nm has been achieved. The blue output power stability over 4 h is better than 3.2%.

Electrochemical and spectrophotometric study on neodymium ions in molten alkali chloride mixtures

The thermodynamic stability of Nd(III) complex in various molten alkali chlorides at 923 K was studied by electrochemical analysis. The standard Gibbs free energy change of the Nd 3+ formation, Δ G 3 / 0 ∘ , decreased by adding MCl (M = Na, K, Rb, or Cs) into LiCl. The Nd(III) complex was more stable in an alkali chloride mixture with larger averaged cationic radius. This means that the stability is controlled by the polarizing power of solvent cations. The electronic absorption spectrum of the hypersensitive f– f transition of Nd 3+ was investigated to know the change in its coordination environments. The oscillator strength of the 4 G 5/2, 2 G 7/2 ← 4 I 9/2 transition and the degree of the energy splitting in electronic energy levels were estimated. The results suggested that the octahedral symmetry of the NdCl 6 3− complex was more distorted in the melt with higher LiCl content, and the distortion was depressed by decreasing the polarizing power of solvent cations. The local structure around Nd 3+ was significantly correlated with the thermodynamic stability of the Nd(III) complex in molten alkali chlorides.

Efficient near-infrared luminescence and energy transfer in Nd-Bi codoped zeolites

ABSTRACTWe prepare Nd-Bi codoped zeolites by a method consisting of a simple ion-exchange process and subsequent high-temperature annealing. The emission covers the range of 970∼1450 nm, corresponding to the electronic transitions of Nd3+ ions and Bi-related active centers (BiRAC), respectively. The introduction of Bi distinctly broadens the excitation band of Nd3+ in the visible region, and the lifetime of Nd3+ reaches as long as 354 μs. In the zeolite matrix, Bi ions exist as BiRAC and Bi oxide agglomerates. The former one act as a sensitizer of Nd3+ ions, and the latter one act as a blockage to avoid the quenching effect of coordinated water, which enable Nd3+ ions to show efficient near-infrared (NIR) emission even the zeolites contain large amount of coordinated water. The excellent optical and structural properties make these NIR emitting nanoparticles promising in application as laser materials and biological probes.

Quasi-three-level laser operation of Nd:Y0.53Gd0.47VO4 mixed vanadate crystal oscillating at 913 nm

Efficient continuous-wave (CW) laser operation on the 4 F 3/2 → 4 I 9/2 transition of Nd:Y0.53Gd0.47VO4, a mixed vanadate crystal, is demonstrated at room temperature employing a compact plano-concave resonator, generating a polarized output power of 0.39 W at 913.2 nm with 2.85 W of pump power absorbed, the optical-to-optical and slope efficiencies being 14 and 25%, respectively.

Quasi-three-level Nd:YVO4 laser by diode pumping at 888 nm

We report efficient laser emission on the 914 nm 4F3/2 to 4I9/2 transition in Nd:YVO4 under the pump with diode lasers at 888 nm for the first time. Continuous wave 6.57 W output power at 914 nm is obtained from a V-type resonator under 18.3 W of absorbed pump power; the slope efficiency with respect to the absorbed pump power was 60.6%. Moreover, intracavity frequency doubling with BiB3O6 (BiBO) nonlinear crystal yielded 1.77 W of deep-blue light at 457 nm with beam quality characterized by an M2 factor of 1.25.

Rotation of the absorption frame as a function of the electronic transition in the Nd^3+:YCa_4O(BO_3)_3 monoclinic crystal

We report the first measurements of the angular distribution of absorption under polarized light corresponding to seven electronic transitions of Nd(3+) ions in the monoclinic crystal Nd:YCOB, revealing a rotation of the symmetry axes of the different patterns.

Hydrothermal Synthesis and Optical Properties of Single-Crystalline Bi<SUB>3.15</SUB>Nd<SUB>0.85</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> Nanoplates of Layered-Perovskite Structure

Single-crystalline Bi3.15Nd0.85Ti3O12 (BNdT) nanoplates of bismuth-layered perovskite structure have been synthesized through hydrothermal process. The BNdT nanoplates possess well-defined tetragonal shapes with landscape dimension of 100-600 nm and thickness of 10-30 nm. The in-plane surfaces of tetragonal-shaped nanoplates lies on (001), and the side surfaces are (110) and (110). The BNdT nanoplates were formed due to the rather higher growth rate of a-b plane than that of c-axis. The optical absorption characteristics in UV-visible region demonstrated that the band gap of the BNdT nanoplates is 3.33 eV. The absorption bands around 516 nm, 526 nm, 585.6 nm, 684.6 nm and 750 nm should be assigned as transitions of Nd3+ from the ground state 4I9/2 to 2G9/2, 4G7/2, 2G7/2 or 4G5/2, 4F9/2 and 4S3/2 states, respectively.

Simultaneous dual-wavelength laser operation at 1342 and 946 nm in two laser crystals and their sum-frequency mixing

A sum-frequency yellow–green laser at 554.9 nm is reported by this paper, 946 nm wavelength is obtained from 4F 3/2– 4I 9/2 transition in Nd:YAG and 1342 nm wavelength is obtained from 4F 3/2– 4I 13/2 transition in Nd:YVO 4. Using a doubly folded-cavity type-II critical phase matching KTP crystal intra cavity to make 946 nm laser from Nd:YAG and 1342 nm laser from Nd:YVO 4 frequency summed, with incident pumped power of 30 W in Nd:YAG and 20 W in Nd:YVO 4, TEM 00 mode yellow–green laser at 554.9 nm at 1.15 W is obtained and its M 2 factor is less than 1.22. The experimental results show that the Nd:YAG and Nd:YVO 4 crystals intra-cavity sum-frequency mixing is an effective method for yellow–green laser and it can be applied to other two laser crystals to obtain more all-solid-state lasers with different wavelengths.

Study of the d-f Emission, and f-d Ground-State and Excited-State Absorption of Nd3+ in Crystals Using the Simple Model

ABSTRACT The simplified model for 4f-5d transitions is applied to obtain the line strengths for emission, ground-state absorption and excited states absorption involving 4f-5d transitions of Nd3+ in crystals. The results are host independent for the usual case where 5d crystal-field interaction can be considered as strong, in the sense that the calculated 5d-4f emission relative line strengths will be the same for Nd3+ in any host. Also the calculated 4f-5d absorption line strengths can be grouped by the 5d crystal-field components. For each 5d crystal-field component, the group of absorption line strengths for different 4f25d transition final states forms a pattern independent of the 5d crystal-field component and the host. For practical cases, due to strong but still limited 5d crystal-field splitting, the transitions to different 5d crystal-field components may overlap each other. The theoretical results are used to interpret available experimental data.

Luminescence properties of Nd 3+-doped (Y,Gd)BO 3 phosphors

A system of 0.03 mol Nd 3+-doped (Y,Gd)BO 3 phosphors were prepared by the conventional solid state reaction method for different concentrations of Gd 3+ ions and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and NIR emission measurements. The emitted radiation was dominated by 1057 nm peak in the NIR region as a result of 4F 3/ 2 → 4I 11/2 transitions of Nd 3+ ions. As the concentration of Gd 3+ ions increases from 0.00 to 0.57 mol, the grain sizes and the intensity of NIR emission peaks were improved. The results are discussed in comparison with similar reported works.

Lanthanide absorption spectral probe in titania nanoparticles synthesized by ultrasonic assistant sol–gel method

Titania nanoparticles were obtained by an ultrasonic assistant sol–gel method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermal analysis. The optical absorption of the samples has been measured by photoacoustic (PA) spectroscopy, which is powerful for detecting small amount of strongly scattering materials. The structural variations of the sample during the phase transitions were firstly studied using Nd 3+ as an absorption spectral probe. The PA results show that the TiO 2 gel heated at 50 °C is basically amorphous and still contains abundant trapped water and ethanol, which makes the environment around Nd 3+ similar with that of its aqueous ion. For the sample calcined at higher temperature, the f–f transitions of Nd 3+ exhibit a continuous red shift along with the gel-to-anatase transformation, indicating an increase of the “degree of covalency” for Nd 3+ bonding. For the sample calcined at 1100 °C, however, the f–f transitions of Nd 3+ show blue shifts and the hypersensitive transition intensities of Nd 3+ decrease, indicating an increase of ionicity for Nd 3+ bonding. This can be attributed to the segregation of Nd 3+ ions to the external surface, forming Nd 4Ti 9O 24 during the anatase-to-rutile transition.

Laser spectroscopy of Nd 3+ and Dy 3+ ions in lead borate glasses

The spectroscopic and laser properties of Nd 3+ and Dy 3+ ions in lead borate glass were studied. Luminescence spectra recorded in the near-infrared and visible ranges correspond to 4F 3/2– 4I J /2 ( J=9, 11, 13) transitions of Nd 3+ and 4F 9/2– 6H J /2 ( J=11, 13, 15) transitions of Dy 3+, respectively. Luminescence decay curves were analyzed as a function of activator concentration. Luminescence quenching is observed, which is due to Ln–Ln interaction increasing. Several spectroscopic parameters relevant to laser potential of Ln 3+ ions (Ln=Nd, Dy) in lead borate glass were determined. The relatively large values of the quantum efficiency and the room-temperature emission cross-section for the 4F 3/2– 4I 11/2 transition of Nd 3+ at 1061 nm and the 4F 9/2– 6H 13/2 transition of Dy 3+ at 573 nm imply that Ln-doped lead borate glasses can be considered as promising solid-state materials for laser applications.