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Herein, we have reported the facile synthesis of pure and neodymium (Nd)-doped BaTiO 3 powders via the hydrothermal method. The effects of Nd concentration (2–10 wt %) on the properties of the BaTiO 3 powders were studied. Structural and morphological characteristics were realized using X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive X-ray (EDS), and X-ray photoelectron spectroscopy (XPS). Fourier transform infrared (FT-IR), UV–visible, and photoluminescence (PL) spectroscopies were used for optical analyses. XRD results show that all powders crystallized under a cubic structure with an average crystallite size that was in the range of 35–47 nm. SEM micrographs revealed that the grains were spherical-shaped, with an average size found in the range of 232–390 nm. The EDS analysis detected the presence of Ba, Ti, O, and Nd elements in the elaborate materials. XPS data confirms the introduction of Nd3+ in the BaTiO 3 and the amphoteric substitution of Nd3+ in the Ba and Ti sites at 6 and 10 wt%. FT-IR spectra indicate the presence of the Ti–O vibration bonds. UV–visible optical spectra illustrate the enhancement of absorbance with Nd doping. PL spectra exhibit ultraviolet, blue, green, and orange emissions in the samples. • Pure and Nd doped BaTiO 3 were elaborated by the hydrothermal method. • The XRD patterns confirmed the integration of Nd3+ ions into the BaTiO 3 host lattice. • The XPS analysis revealed the amphoteric substitution of Nd3+ in the Ba and Ti sites at 6 and 10 wt%. • Enhancement of the samples 'absorbance with Nd doping. • The emergence of the orange emission in the doped BaTiO 3. [ABSTRACT FROM AUTHOR]

Neodymium doping of photo-thermo-refractive (PTR) glass leads to a fast non-radiative depopulation of excited states of cerium ions, which are responsible for the glass photosensitivity. The non-radiative energy transfer from cerium to neodymium ions results in a decrease in the efficiency of photoelectron generation under UV irradiation. Emission spectra and fluorescence decay curves of cerium ions under UV excitation were investigated. Absorption spectra of the glasses were obtained as well to distinguish the reabsorption processes and the non-radiative energy transfer mechanisms. It was found that as Nd 2 O 3 concentration increases from 0 to 2 mol%, cerium ions average lifetime decreases from 44.5 to 28 ns, while the energy transfer efficiency reaches 37 %. It was also found that Förster resonance energy transfer may compete with other relaxation mechanisms and the Förster distance for the Ce3+-Nd3+ pair in PTR glass is ∼0.33 nm. This study has important implications for future research; it informs future studies on optimizing the photosensitivity of the PTR glass and choosing rare-earth activators. • Doping of photo-thermo-refractive glass with Nd3+ ions reduces the glass photosensitivity. • Non-radiative ET from Ce to Nd leads to fast depopulation of Ce and decreases the efficiency of photoelectron generation. • Energy transfer efficiency increases from 5 to 37 % when increasing neodymium concentration from 0.25 to 2 mol%. [ABSTRACT FROM AUTHOR]

A detailed spectroscopic characterization of CaF 2 co-doped with neodymium and ytterbium ions is presented. The higher Nd3+ absorption cross-section around 791 nm than Yb3+ around 980 nm enables an efficient excitation of Yb3+ ions by pumping Nd3+ with a subsequent energy transfer (ET) from Nd3+ to Yb3+ ions. By combining Nd3+ and Yb3+, along with Gd3+ buffer ions Nd3+,Yb3+,Gd3+:CaF 2 crystals exhibit very large emission bands extending the usual Yb3+ emission spectrum by adding the Nd3+ emission contribution at longer wavelengths. The Nd3+ ⟶ Yb3+ energy transfer efficiency is estimated using two different approaches based on luminescence intensity measurements and lifetimes, giving consistent results. An energy transfer efficiency of 80 % is achieved in CaF 2 :0.5%Nd,3%Yb,2%Gd illustrating the ET strength within Nd3+-Yb3+ clusters. Finally, a detailed study of the gain cross-sections and laser emission spectra, and their dependence with Yb3+ doping concentration and population inversion is carried out, providing a detailed model of the laser spectral dynamics in such crystals. The gain cross-section is either dominated by one of the Nd3+ peaks at 1065 nm or 1048 nm or exhibits a flat profile covering the 1045–1067 nm range, in which case the laser oscillates randomly over this spectral range. The results highlight the specifics of the Nd3+ four level laser coupled by energy transfer to the Yb3+ quasi three level laser. Among others, this study shows how a large Nd3+ inversion ratio initiates the depletion of the Yb3+2F 7/2 ground state through the ET. This depletion then has two effects as it saturates the energy transfer since the number of Yb3+ acceptors diminishes and it also shifts the laser wavelength towards shorter wavelength as the Yb3+ laser reabsorption is weakened. • Demonstration of strong energy transfer from Nd to Yb within Nd–Yb clusters. • Determination of energy transfer efficiency using two different methods based on luminescence intensity and lifetimes. • Continuous Laser operation at 1065 nm or 1045 nm with a 17 % slope efficiency and a typical 200 mW laser threshold. • Successful comparison between measured laser spectral dynamics and simulations of coupled Nd3+ and Yb3+ active ions. [ABSTRACT FROM AUTHOR]

Abstract Electrical properties of NdAP nanocrystalline ceramic under 808 nm laser excitation were investigated in the context of photo-induced signal current amplification or switching. Spectroscopic properties under identical excitation conditions are evaluated as a reinforcement for investigation of mechanisms of the observed phenomena. The application potential of NdAP in optoelectronic devices is commented upon. [ABSTRACT FROM AUTHOR]

Abstract A garnet-type optical current sensor (OCS) is studied. Ta/Nd 2 Fe 14 B/Ta groove films are prepared on garnet by a magnetron sputtering method. The measurement errors of the Faraday rotation angle and the Verdet constant of the garnet-type and garnet-groove film OCSs are measured by Thorlabs polarimeters as a function of temperature. The results show that the measurement errors of the Faraday rotation angle of the garnet-type and garnet-groove film OCSs are 1.5% and 0.3%, respectively, when the current is 700 A at room temperature. The measurement error of the garnet-groove magnetic film OCS is lower than 0.3%, when the current changes from 0 to 1000 A and the temperature changes from 25 °C to 80 °C. The Verdet constant variations of the garnet-type and garnet-groove film OCSs cause different measurement errors when the temperature is changed. Highlights • A garnet-type optical current sensor (OCS) is studied. • The measurement error of Faraday rotation angle of the garnet-type OCS is 1.5%. • The measurement error of the garnet-groove film OCS is lower than 0.3%. • The Verdet constant variation of the garnet-type and garnet-groove film OCS cause different measurement errors. [ABSTRACT FROM AUTHOR]

Abstract We report on diode-pumped continuous-wave and passively Q-switched c-cut Nd:LMA lasers. For continuous-wave operation, the maximum output power reaches 3.10 W with slope efficiency of about 48.9% at 1055 nm and 2.63 W with slope efficiency of 43.1% at 1082 nm. For passively Q switched operation, using a Cr:YAG as saturable absorber, the achieved maximum average output power is 1.49 W at 1055 nm with pulse width of 18.4 ns. Moreover, we have also realized simultaneous dual-wavelength laser operation at 1055 and 1082 nm with a maximum average output power of 1.22 W and a pulse width of 19.4 ns. Furthermore, inserting an etalon for suppressing the 1055 nm line, we have operated single wavelength laser at 1082 nm with output power of 0.31 W and pulse width of 20.8 ns. This work has verified the potential of Nd:LMA crystal as a laser gain medium. Highlights • Absorption and emission spectra of a c -cut Nd: LaMgAl 11 O 19 crystal are reported. • Efficiently continuous-wave operation at 1055 and 1082 nm have been realized for the first time to our knowledge. • Efficiently passively Q-switched operation at 1055 and 1082 nm have also been realized. [ABSTRACT FROM AUTHOR]

Abstract Crystal field parameters of neodymium impurity centers in YVO 4 single crystals were determined using data of CW EPR spectroscopy and the known energy level schemes. The spin echo spectroscopy was used to determine spin-lattice and spin-spin relaxation times of the 143Nd3+ and 145Nd3+ impurity ions in YVO 4 single crystal. Graphical abstract Image 1 Highlights • Crystal-field parameters of neodymium in yttrium orthovanadate were determined. • Spin-lattice and spin-spin relaxation times for neodymium were determined. • Comparison of the results, obtained in this work and results from other works, was done. [ABSTRACT FROM AUTHOR]

Abstract Intense blue and near-infrared emissions were observed in Ca 10 (PO 4) 6 O:Eu2+ and Ca 10 (PO 4) 6 O:Eu2+,Nd3+ phosphors. The emissions can be excited by broad band in near ultraviolet region. Blue emission is characterized by CIE coordinates 0.1519, 0.0696 which can be useful as a blue component of LED lamp based on near ultraviolet chips. Near-infrared emission is obtained as a consequence of Eu2+→Nd3+ energy transfer. The efficiency of Eu2+→Nd3+ energy transfer is as high as 95%. Fast (10 ns) and slow (300 ns) components observed in decay curves could be identified with isolated Eu2+ and Eu2+ ions near Nd3+, respectively. NIR Emission intensity is limited by Nd3+→Nd3+ energy transfer and the consequent concentration quenching. Critical distances for Eu2+→Eu2+ and Nd3+→Nd3+ energy transfers are 18.86 and 12.62 Å, respectively. Absorption of near ultraviolet radiations followed by conversion to blue/NIR indicates the potential applications in solid state lighting and solar photovoltaics. Graphical abstract Image 1 Highlights • Blue and NIR emissions in Ca 10 (PO 4) 6 O:Eu2+,Nd3+ reported. • NIR emission and excitation spectra correlated with Eu2+.→Nd3+ energy transfer • Energy transfer efficiency of nearly 95%. • NUV excitation and blue emission suitable for solid state lighting. • NUV excitation and NIR emission suitable for solar photovoltaics. [ABSTRACT FROM AUTHOR]

Undoped, 0.1 at% Nd and 0.1 at% Pr doped GaSe single crystals were grown by using modified Bridgman method. The nonlinear absorption (NA), second harmonic generation (SHG) and carrier dynamics of undoped, 0.1 at% Nd and 0.1 at% Pr doped GaSe single crystals have been studied by open aperture Z-scan, SHG and transmission ultrafast pump probe spectroscopy experiments, respectively. All of the studied crystals showed nonlinear absorption under 100 fs pulse duration and 1200 nm wavelength excitations. It was found that the doping of Nd 3+ and Pr 3+ into GaSe single crystals caused shifting of SHG signal peaks to the shorter wavelengths. However, transmission pumb-probe experiments revealed that all of the crystals showed NA signals with long lifetime under 620 nm pump and 626 nm probe excitations. [ABSTRACT FROM AUTHOR]

Intense near-infrared emitting phosphor K 2 SrCl 4 :Eu 2+ ,Nd 3+ with various concentrations of Nd 3+ were synthesized. These are characterized with X-ray diffraction, reflectance, photoluminescence emission and photoluminescence excitation spectroscopy, PL lifetime measurements. The emission can be excited by a broad band in near ultra violet region as a consequence of Eu 2+ →Nd 3+ energy transfer. The efficiency of Eu 2+ →Nd 3+ energy transfer is as high as 95%. Fluorescence decay curves for Eu 2+ doped samples are almost exponential and described by τ = 500 ns. Eu 2+ lifetimes are shortened after Nd 3+ doping. Near infrared Emission intensity is limited by Nd 3+ →Nd 3+ energy transfer and the consequent concentration quenching. Nd 3+ emission matches well with the spectral response of CIGS and CIS solar cells. Absorption of near ultra violet radiations followed by conversion to near infrared indicates the potential application in solar photovoltaics. [ABSTRACT FROM AUTHOR]

YAlO 3 (YAP) single crystals doped with Lu and Nd were grown by the Floating Zone (FZ) method to evaluate their scintillation properties particularly emissions in the near-infrared (NIR) range. The Nd concentration was fixed to 0 or 1 mol% while the Lu concentration was varied from 0 to 30%. When X-ray was irradiated, the scintillation of Nd-doped samples was observed predominantly at 1064 nm due to 4 F 3/2  →  4 I 11/2 transition of Nd 3+ . In contrast, a weak emission around 700 nm appeared in the samples doped with only Lu, and the emission origin was attributed to defect centers. In the Nd 3+ -doped samples, the decay time was 94–157 μs due to the 4f-4f transitions of Nd 3+ whereas the Lu-doped samples showed signal with the decay time of 1.45–1.54 ms. The emission origin of the latter signal was attributed to the perovskite lattice defect. [ABSTRACT FROM AUTHOR]

Due to their very fast short-wavelength emission, neodymium-doped materials are a subject of current interest as potential scintillators. Although the initial reports regarding neodymium-doped orthophosphates (in crystalline form) and their scintillation properties appeared almost twenty years ago, they remain an interesting class of materials since there is no in-depth understanding of their fundamental scintillation mechanism. In the present research, we focus on the crystalline systems: XPO 4 :Nd 3+ , where X = Y, Lu, La, Sc. The pulse height, optical absorption, radioluminescence and photoluminescence spectra were investigated and are reported here for various temperatures from 10 to 350 K. Additionally, results of both low and high temperature thermoluminescence measurements are reported in this communication. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) luminescent nanophosphor of Nd 3+ and Bi 3+ co-doped GdVO 4 was prepared by a microwave-assisted hydrothermal method. The phase purity and the structure of samples were characterized by an X-ray powder diffraction (XRD). The optical properties were investigated by analysis of the photoluminescence and excitation spectra and by the emission decay measurements. It was found that upon near-UV excitation of the charge transfer state or the Bi 3+ ions absorption, a strong broad band yellow-green emission of Bi 3+ ions accompanied with NIR emission of Nd 3+ ions is observed. Enhancement of the Nd 3+ emission through an energy transfer from the (O 2− – V 5+ ) or the (Bi 3+ – V 5+ ) charge transfer states to the excited states of Nd 3+ ion was noticed and the possible energy transfer mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Lanthanide-doped Y 2 SiO 5 microcrystals were prepared using the solution combustion, solid state and sol–gel synthesis techniques. Of these, the sol–gel method yields the most reliable and high-quality X2 phase Y 2 SiO 5 microcrystals. Absorption and laser site-selective fluorescence measurements of Nd3+, Eu3+ and Er3+ doped material, performed at cryogenic temperatures, indicate that the as-grown microcrystals are of high optical quality with inhomogeneously broadened optical linewidths that are comparable to bulk crystals at similar dopant concentrations. • Spectroscopy of Y 2 SiO 5 microcrystals doped with Eu3+, Nd3+ and Er3+ is presented. • Y 2 SiO 5 Microcrystals grown by sol–gel methods are shown to produce the highest phase purity. • Y 2 SiO 5 Microcrystals doped with Er3+ show inhomogeneous linewidths as low as 12 GHz. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the principal role of Y 2 O 3 , Sc 2 O 3 and HfO 2 on the enhancement of 1.06 μm emission beam of Nd 3+ ion in PbO–Sb 2 O 3 glass system. The emission spectrum of Nd 3+ doped glass exhibited emission bands at 900, 1060 and 1335 nm. When the glasses are co-doped with Y 2 O 3 , Sc 2 O 3 and HfO 2 and excited at 528 nm, a substantial hike in the intensity of 1060 nm emission band is observed. The comparison of luminescence efficiency of Nd 3+ ion of the glasses mixed with three co-dopants indicated the highest enhancement in the intensity of this emission in the glass co-doped HfO 2 . The reasons for such enhancement have been discussed in the light of varying environment of the glass network in the vicinity of Nd 3+ rare earth ions. [ABSTRACT FROM AUTHOR]

The CW and passively Q-switched operation of a Nd:GYSGG laser is demonstrated. In the CW operation, triple-wavelength lines at 1323.9, 1331.6 and 1336.8 nm are generated simultaneously. The maximum CW output power is 1133 mW under a pump power of 7.85 W. In the passively Q-switched operation, a Co:MgAl 2 O 4 crystal with initial transmission of 82% is employed, only single-wavelength line at 1331.6 nm is realized. The narrowest pulse width of 20.5 ns is achieved with an output power of 225 mW under the same pump power. The highest peak power and pulse energy are 1319 W and 27.2 μJ under a pump power of 7.20 W, respectively. [ABSTRACT FROM AUTHOR]

CaF 2 nanoparticles activated with Nd 3+ ions have been investigated as potential optical nanothermometers in the biological windows. The variation of the Nd 3+ emission around 850 and 1060 nm as a function of the temperature has been measured. A ratiometric approach, based on the relative changes in the intensities of different emission bands of the Nd 3+ has been considered to investigate the thermometric properties of the NPs. The evaluated thermal sensitivity is around 0.12% K −1 , a value that is similar to those found for other water dispersible nanothermometers based on the near-infrared luminescence of the Nd 3+ lanthanide ion. The temperature uncertainty is around 1.8 °C, small enough to monitor the local temperature during a photothermal treatment. [ABSTRACT FROM AUTHOR]

Nd 2 O 3 -doped calcium aluminate glasses was synthesized with the following compositions: (100−x)(33Al 2 O 3 -62CaO-2MgO-3BaO)-xB 2 O 3 -0.5Nd 2 O 3 (x = 0, 2.5, 5, 7.5, 10). The Raman, absorption, and emission spectra were measured to characterize the structure and spectroscopic properties of these glasses. The glass thermal stability was studied using differential scanning calorimetry (DSC) tests. Both the Raman spectra and DSC results indicated a decrease in the non-bridging oxygens (NBOs) in the [AlO 4 ] − network with an increase in the B 2 O 3 content. The J-O intensity parameter Ω 2 , covalency degree of the Nd-O bond, and emission bandwidth of the Nd 3+ ions decreased with the B 2 O 3 content. The stimulated emission cross-section and optical gain property increased with an increase in the B 2 O 3 content. The tunable gain property and broadband emission feature of the Nd 3+ -doped CaO-Al 2 O 3 -B 2 O 3 -MgO-BaO calcium aluminate glass suggested a potential application to a high-energy ultra-short-pulse laser. [ABSTRACT FROM AUTHOR]

Nd 3+ -doped P 2 O 5 -K 2 O–Al 2 O 3 –BaO-PbO phosphate glasses with various PbO/BaO ratios were synthesized using the melt quenching technique. Raman, absorption, and emission spectra were measured to investigate the effects of PbO/BaO ratios on the structures and spectroscopic properties of the glasses. The emission cross-sections of the Nd 3+ -doped phosphate glasses were calculated using the Judd–Ofelt theory, and were found to increase from 4.37 × 10 −20 to 4.50 × 10 −20 cm 2 as the PbO/BaO ratio increased. In addition, thermo-optical properties were measured using an interferometric technique. The thermo-optical coefficients, which were −1.49 × 10 −6 , −1.65 × 10 −6 , and −1.64 × 10 −6 K −1 , respectively, were all largely negative values. The thermal expansion coefficients of the three glass samples varied within a small range. The results showed that increasing the PbO/BaO ratio of phosphate glasses can improve the laser properties while maintaining their good thermo-optical properties. [ABSTRACT FROM AUTHOR]

Transparent 1.0 at% Nd:Lu 2.7 Gd 0.3 Al 5 O 12 (Nd:LuGdAG) ceramics were fabricated by the solid-state reactive sintering method using commercial powders as starting materials. The powders were mixed in ethanol with tetraethoxysilane (TEOS) and MgO, dried and pressed. The compacts were vacuum-sintered from 1725 °C to 1800 °C for observing the microstructure and the optical transmittance of Nd:Lu 2.7 Gd 0.3 Al 5 O 12 ceramics. The sample sintered at 1800 °C for 10 h has an almost dense and homogenous structure with the average grain size of 12.8 μm, whose in-line transmittance is about 70% at 1064 nm. The absorption and emission cross sections were calculated to be 1.0 × 10 −20 cm 2 and 1.23 × 10 −18 cm 2 , respectively. It is proved that Nd:LuGdAG ceramics have the potential to be a new solid-state laser material. [ABSTRACT FROM AUTHOR]

The influence of grain size and neodymium concentration on the threshold and absolute slope efficiency of the stimulated emission of LiLa 1-x Nd x P 4 O 12 (x = 0.1, 0.5, and 1) crystalline powders has been investigated by using a pulsed Ti-sapphire pumping. The absolute slope efficiencies are similar for the studied samples with x = 0.5 and 1 whereas the lowest threshold pump energy corresponds to the stoichiometric sample with an average grain size of around 20 μm. The grain size also affects the emitting surface of the random laser due to the reduction of the difussive length as grain size decreases. The experimental results show the importance of seeking the optimal grain size for a given material. [ABSTRACT FROM AUTHOR]

Monoclinic monazite-type Nd 3+ -doped lanthanum orthophosphate (LaPO 4 :Nd 3+ ) nanoparticles were prepared by microwave treatment of simple lanthanide precursors such as Nd(OAc) 3 •xH 2 O, OAc = acetate) with task-specific dihydrogen phosphate ionic liquids (ILs) 1-butyl-1-methylpyrrolidinium dihydrogenphosphate- BmPyrH 2 PO 4 (IL1) and 2-hydroxyethyl-N,N,N-trimethylammonium, [choline][H 2 PO 4 ] (IL2) as the reaction medium, reactant and in-situ nanoparticle stabilizer. This synthesis route possesses many advantages as it is a fast and facile preparation method of the desired phosphate nanomaterials without the necessity for post-reaction heat treatment to obtain the anhydrous high temperature monazite phosphate phase. The nano-sized phosphors Nd 3+ :LaPO 4 were carefully analyzed by the powder X-ray diffraction, electron microscopy and spectroscopic techniques taking advantage of the Nd 3+ spectroscopic probe to analyze in detail the structural properties. Applied high resolution low temperature absorption and emission techniques allowed to complete the structural information unavailable from the XRD powder patterns. A clear influence of the used task-specific dihydrogen phosphate ILs on the structure, morphology, luminescence intensity and lifetimes of the obtained Nd 3+ :LaPO 4 was found. It is worth noting that the Nd 3+ luminescence in LaPO 4 has never been reported up to now. [ABSTRACT FROM AUTHOR]

In this work we evaluate the impact that neodymium ions can have in modern nanomedicine when they are incorporated as optically active dopants in nanocrystals. In particular, we here discuss how the particular absorption and emission properties of this ion can be conveniently exploited for important biomedical applications, such as fluorescence imaging at both in vitro and in vivo level, non-contact nanothermometry and photothermal therapy. All these features can confer neodymium-doped nanoparticles a multifunctional character and so Nd 3+ is also envisaged as a paradigm ion for nanoparticle based theranostic applications. [ABSTRACT FROM AUTHOR]

Trivalent neodymium (Nd 3+ ) can be used as high performance temperature luminescent ion sensor, namely in the near infrared spectral region. The disadvantage presented in the use of this ion is that transitions from thermally coupled levels show very different emission intensities. In order to solve this critical problem we propose to use Nd 3+ -doped fluoroindogallate glasses with low phonon cutoff energy (500 cm −1 ) as the active medium. By using a dopant concentration that minimizes losses due to cross relaxation processes and detecting the emissions of the thermally coupled levels with a R928 photomultiplier, without correction response for the wavelength dependence of the intensity, we have succeeded in getting the highest relative thermal sensitivities so far observed, 2.5%⋅K −1 and 7.4%⋅K −1 , for the 4 F 5/2 → 4 I 9/2 / 4 F 3/2 → 4 I 9/2 and 4 F 7/2 → 4 I 9/2 / 4 F 3/2 → 4 I 9/2 intensity ratios, respectively at 288 K. [ABSTRACT FROM AUTHOR]

Ridge waveguide lasers have been fabricated on Nd 3+ doped LiNbO 3 crystals. The fs-laser writing technique was used to define ridge structures on a gradient-index planar waveguide fabricated by Zn-diffusion. This planar waveguide was formed in a z -cut LiNbO 3 substrate homogeneously doped with a 0.23% of Nd 3+ ions. To obtain lateral light confinement, the surface was then micromachined using a multiplexed femtosecond laser writing beam, forming the ridge structures. By butting two mirrors at the channel waveguide end-facets, forming a waveguide laser cavity, TM-polarized laser action at 1085 nm was achieved by end-fire TM-pumping at 815 nm. The waveguide laser shows a threshold of 31 mW, with a 7% of slope efficiency. [ABSTRACT FROM AUTHOR]

We have demonstrated continuous wave (CW) laser operation of Nd:YNbO 4 crystal at 1066 nm for the first time. A maximum output power of 1.12 W with the incident power of 5.0 W is successfully achieved corresponding to an optical-to-optical conversion efficiency of 22.4% and a slope efficiency of 24.0%. The large absorption cross section (8.7 × 10 −20 cm 2 ) and wide absorption band (6 nm) at around 808 nm indicates the good pumping efficiency by laser diodes (LD). The small emission cross section (29 × 10 −20 cm 2 ) and relative long lifetime of the 4 F 3/2 → 4 I 11/2 transition indicates good energy storage capacity of Nd:YNbO 4 . Moreover, the raw materials of Nd:YNbO 4 are stable, thus, it can grow high-quality and large-size by Czochralski (CZ) method. Therefore the Nd:YNbO 4 crystal is a potentially new laser material suitable for LD pumping. [ABSTRACT FROM AUTHOR]

A study of the optical, spectral-luminescent and holographic properties of the chlorine-containing photo-thermo-refractive (PTR) glass doped with neodymium ions was carried out. The chlorine-containing PTR glass has been recently produced by replacing the bromine in the standard PTR glass with chlorine. The glass was doped with different concentrations of neodymium ions. The spectroscopic analysis of neodymium in the glass has been performed using the Judd-Ofelt theory based on experimental absorption and emission measurements. Spectroscopic parameters, such as the Judd-Ofelt intensity parameters, radiative and non-radiative transition probabilities, fluorescence lifetimes, stimulated emission cross-sections, and branching ratios, were obtained and found to be comparable with the parameters of the standard PTR glass doped with neodymium. The mechanism of non-radiative energy transfer was analyzed based on the lifetime kinetics measurements. It was found that cross-relaxation among neodymium ions is the dominant non-radiative energy transfer mechanism. Holographic characteristics of the chlorine-containing PTR glasses doped with neodymium have been also studied. The volume Bragg grating was recorded in the doped and undoped glasses. It was found that the UV exposure and heat treatment do not change the spectroscopic characteristics of neodymium ions in the glasses, while the neodymium ions reduce the sensitivity of the glass. The energy transfer from cerium to neodymium when irradiating using the 325-nm laser makes the hologram recording possible on the samples of low neodymium concentrations only. Studying the spectroscopic and holographic properties of the chlorine-containing PTR glass doped with neodymium ions demonstrates the potential of using such a material in the applications of photonics integration and monolithic optical devices like distributed-feedback lasers. • Spectroscopic properties of Nd ions in Cl-PTR glass are comparable to those of Nd in the standard (Br-PTR) glass. • VBG was recorded in the undoped Cl-PTR glass, as well as in the glass doped with Nd. • UV exposure and heat treatment do not affect the spectral-luminescent properties of Nd in the Cl-PTR glass. • Nd reduces the photosensitivity of Cl-PTR due to energy transfer from Ce to Nd during the hologram recording at 325 nm. [ABSTRACT FROM AUTHOR]

Ca 9 Nd(VO 4 ) 7 single crystal was grown by the Czochralski method in inert atmosphere. The crystal structure and chemical composition were studied. Polarized absorption and luminescence spectra were investigated in details. It was found that the Ca 9 Nd(VO 4 ) 7 crystals belongs to self-activated laser materials with a weak concentration quenching of luminescence. Judd-Ofelt analysis was performed. The emission cross-sections spectra for 4 F 3/2 → 4 I 9/2 , 4 I 11/2 , 4 I 13/2 transitions were determined. For the first time Raman spectra of the Ca 9 Nd(VO 4 ) 7 single crystal were recorded and interpreted. [ABSTRACT FROM AUTHOR]

Frequency upconversion (UC) photoluminescence (PL) in GeO 2 -PbO glass codoped with trivalent ions of neodymium (Nd 3+ ) and ytterbium (Yb 3+ ) is reported. A diode laser operating at 977.7 nm, in resonance with the ytterbium transition 2 F 7/2 → 2 F 5/2 , was the excitation source. Four PL spectral lines, corresponding to the Nd 3+ transitions 4 G 9/2 → 4 I 9/2 (at 500 nm), 4 G 7/2 → 4 I 9/2 (at 550 nm), [ 4 G 5/2 ; 2 G 7/2 ] → 4 I 11/2 (at 595 nm) and 4 G 7/2 → 4 I 13/2 (at 660 nm), were observed and characterized. The quadratic dependence of the PL intensities versus the laser power indicates that two laser photons participate in the UC process. The temperature dependence of the PL emissions from 300 to 390 K was also investigated to identify the contribution of phonons for the UC process. The dependence of the UC intensity with the Yb 3+ concentration and the time behavior of the UC signal indicated the presence of two energy transfer (ET) pathways involving Nd 3+ -Yb 3+ pairs and Yb 3+ -Nd 3+ -Yb 3+ triads. Rate-equations for the population densities of the rare-earth energy levels were used to describe the dynamics of the UC emission and to determine the ET rates. [ABSTRACT FROM AUTHOR]

Infrared photoluminescence (PL) properties of PbO-GeO 2 glasses containing neodymium ions (Nd 3+ ) and silver nanoparticles (NPs) were investigated. The excitation was made with a continuous-wave diode laser operating at 805 nm, in resonance with the Nd 3+ transition 4 I 9/2 → 4 F 5/2 . Growth of ∼160% in the PL intensity at 1064 nm, was observed in comparison with a reference sample without silver NPs. The PL enhancement is attributed to the increased local-field in the Nd 3+ locations nearby the NPs. The present results indicate that PbO-GeO 2 glasses containing Nd 3+ and silver NPs have good prospect to be used in optical amplifiers at 1064 nm. [ABSTRACT FROM AUTHOR]

Radioluminescence spectra at temperatures ranging from 10 to 320 K and low temperature thermoluminescence glow curves of BaY 2 F 8 :Ce and BaY 2 F 8 :Nd scintillator crystals have been investigated. In both materials the intensities of the excitonic and the activator ion’s emission at X-ray excitation vary with temperature, anticorrelating with each other, which provides valuable information on the host-to-ion energy transfer. Detailed thermoluminescence studies, in turn, prove the existence of charge traps, which introduce quasi-continuous distributions of energy levels into the bandgap. [ABSTRACT FROM AUTHOR]

High-resolution absorption and stimulated-emission cross-section spectra are presented for monoclinic Nd:KGd(WO 4 ) 2 (Nd:KGW) laser crystals in the temperature range 77–450 K. At room-temperature, the maximum stimulated emission cross-section is σ SE = 21.4 × 10 −20 cm 2 at 1067.3 nm, for light polarization E || N m . The lifetime of the 4 F 3/2 state of Nd 3+ in KGW is practically temperature independent at 115 ± 5 μs. Measurement of the energy transfer upconversion parameter for a 3 at.% Nd:KGW crystal proved that this was significantly smaller than for alternative hosts, ∼2.5 × 10 −17 cm 3 /s. When cut along the N g optical indicatrix axis, the Nd:KGW crystal was configured as a microchip laser, generating ∼4 W of continuous-wave output at 1067 nm with a slope efficiency of 61% under diode-pumping. Using a highly-doped (10 at.%) Nd:KGW crystal, the slope efficiency reached 71% and 74% when pumped with a laser diode and a Ti:Sapphire laser, respectively. The concept of an ultrathin (250 μm) Nd:KGW microchip laser sandwiched between two synthetic diamond heat-spreaders is demonstrated. [ABSTRACT FROM AUTHOR]

The present work reports the modification introduced by different Nd 2 O 3 concentration on optical properties and the laser operation of Nd 3+ doped (TeO 2 -ZnO) bulk tellurite glass. The spectroscopic data are analyzed within the Judd Ofelt formalism framework and the results are compared to the fluorescence lifetime and emission measurements to derive values for the quantum efficiency and the stimulated emission cross section of the considered 4 F 3/2 → 4 I 11/2 infrared laser transition around 1062.5 nm. Continuous-wave laser action is achieved with this bulk tellurite glass by pumping the sample inside a standard plan-concave mirror laser cavity with different output couplers. It is possible to observe coherent emission only for the lower concentration (0.5%(wt.) of Nd 2 O 3 ). Also laser action could only be observed for this sample with threshold pump power of 73 mW associated with a laser slope efficiency of 8% for an output coupler transmission of 4% indicating that TeO 2 -ZnO are potential materials for laser action. The results presented in this work together with those previously reported with higher concentration (1.0% (wt) of Nd 2 O 3 ) determine the adequate Nd 2 O 3 concentration for laser action and guide the correct experimental procedure for TeO 2 -ZnO glasses preparation. [ABSTRACT FROM AUTHOR]

Neodymium doped cadmium alkali borate glasses having composition 20CdO 20R 2 O 59.5H 3 BO 3 0.5Nd 2 O 3 ; (R = Li, Na and K) were prepared by conventional melt-quenching technique. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. The physical properties such as density, refractive index, molar volume, rare earth ion concentration etc. were determined. Optical absorption and fluorescence spectra were recorded. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω 2 , Ω 4 and Ω 6 . These parameters were in turn used to predict the radiative properties such as the radiative transition probability (A), radiative lifetime ( τ R ) and branching ratio ( β R ) for the fluorescent levels of Nd 3+ ion in the present glass series. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω 4 /Ω 6 ), the value of which is in the range of 0.2–1.5, typical for Nd 3+ in different laser hosts. The variation of Ω 2 with the change in alkali oxide has been attributed to the changes in the asymmetry of the ligand field at the rare earth ion site. The shift of the hypersensitive bands, study of the oscillator strengths and the variation of the spectral profile of the transition 4 I 9/2 → 4 F 7/2 + 4 S 3/2 indicate a maximum covalency of Nd O bond for glass with potassium ions. From the fluorescence spectra, peak wavelength (λ p ), effective line widths (Δλ eff ) and stimulated emission cross-section (σ p ) have been obtained for the three transitions 4 F 3/2 → 4 I 9/2, 4 F 3/2 → 4 I 11/2 and 4 F 3/2 → 4 I 13/2 of Nd 3+ ion. The relatively high values of σ p obtained for Nd 3+ in present glass system suggest that these materials can be considered as suitable candidates for laser applications. The glass with potassium ions shows the highest value of the stimulated emission cross-section. [ABSTRACT FROM AUTHOR]

We report on the fabrication of Nd:YCa 4 O(BO 3 ) 3 (Nd:YCOB) ridge waveguides by combining carbon ion irradiation and precise diamond blade dicing. The guiding and spectroscopic properties of the planar as well as ridge waveguides are investigated. The second harmonic generation (SHG) at 532 nm has been realized through the waveguide structures. With nearly the same input power, the maximum average output powers are 0.56 mW and 0.62 mW, and the maximum conversion efficiencies reach 0.3%W −1 and 0.5%W −1 , for planar and ridge waveguides, respectively. [ABSTRACT FROM AUTHOR]

Calibrated room temperature polarized emission spectra recorded between 850 and 1400 nm and nearly free from any reabsorption effect are presented for the first time. A laser output power of 2.35 W is obtained at 1063.45 nm with a laser slope efficiency of about 56% by pumping an uncoated Nd:LaF 3 single crystal with a fiber-coupled laser diode at 790 nm inside a standard two-mirror linear laser cavity. True dual-wavelength laser operation on two orthogonally polarized laser lines around 1040 and 1065 nm as well as continuous laser wavelength tuning around 1040 nm, 1048 nm and 1064 nm are also achieved for the first time by using either an intracavity etalon or a birefringent filter. Laser operation is finally obtained around 1330.73 nm with a maximum output power of 0.18 W and a laser slope efficiency of about 4% and simultaneous dual-wavelength laser operation at 1329.04 and 1359.67 nm is demonstrated by using a glass etalon. [ABSTRACT FROM AUTHOR]

Polarized absorption spectra of f – f transitions 4 I 9/2 → 4 F 3/2 and ( 2 H 9/2 + 4 F 5/2 ) in the Nd 3+ ion in the Nd 0.5 Gd 0.5 Fe 3 (BO 3 ) 4 single crystal were studied as a function of temperature in the range of 2–40 K and as a function of magnetic field in the range of 0–65 kOe at 2 K. It was found out that the selection rules for f – f electron transitions substantially changed in the magnetically ordered state of the crystal, and they strongly depended on the orientation of the Fe and Nd ions magnetic moments relative to the light polarization. The splitting of the ground and excited states of the Nd 3+ ion in the exchange field of the Fe sublattice were determined. It was revealed that the value of the exchange splitting (the exchange interaction) in the excited states did not correlate with the theoretical Landé factors. The Landé factors of the excited states were experimentally found. In general, the local magnetic properties in the vicinity of the excited ion depend substantially on its electron state. In particular: (1) in one of the excited states a weak ferromagnetic moment appears, (2) the changes of type of the local magnetic anisotropy take place in some excited states, and (3) in some excited states the energetically favorable orientation of the Nd 3+ ion magnetic moment is opposite to that in the ground state. In some excited states the nonequivalent Nd 3+ centers were found out. [ABSTRACT FROM AUTHOR]

X-ray luminescence properties of LiLa 1− x Nd x P 4 O 12 nanocrystals were investigated for the first time. The influence of the Nd 3+ concentration on the integral emission intensities in visible and near infrared emission region were investigated. It was found that emission from 2 F(2) 5/2 is strongly affected by cross-relaxation process and its intensity decreases exponentially with Nd 3+ amount, while emission from 4 F 7/2 + 4 S 3/2 , 4 F 5/2 + 2 H 11/2 , and 4 F 3/2 states rises up sublinearly with Nd 3+ concentration. The size effect on emission spectra under X-ray excitation was presented. [ABSTRACT FROM AUTHOR]

Neodymium or ytterbium-doped transparent yttrium oxide ceramics with different tetravalent sintering additives (ZrO 2 , HfO 2 , or CeO 2 ) were fabricated from nanopowders produced by laser ablation method. Phase composition and distribution of dopants in the synthesized nanopowders and ceramics were studied by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX) spectroscopy. The tetravalent additives led to a decrease in grain size and an improvement in transmittance at the lasing wavelengths. However, an excess of tetravalent ions led to the formation of dispersed scattering volumes. We observed particles with modulated composition for nanopowder of Nd:Y 2 O 3 doped by 10 mol% HfO 2 . The estimations based on Rayleigh light scattering showed that the maximum size of the dispersed scattering volume is below 20 nm. [ABSTRACT FROM AUTHOR]

The sintering behavior of neodymium doped yttrium aluminum garnet (Nd:YAG) ceramics was investigated on the basis of densification trajectory, microstructure evolution and transmittance. Nd:YAG ceramics with in-line transmittance of 83.9% at 1064 nm and 82.5% at 400 nm were obtained by direct cold isostatic pressing (CIP) at 250 MPa and solid-state reactive sintering at 1790 °C for 30 h under vacuum. Compared with the porosity and the average pore diameter of the sample from uniaxial dry-pressing followed by CIP, those from direct CIP are much smaller. The samples pressed at 250 MPa were sintered from 1500 °C to 1750 °C for 0.5–20 h to study their sintering behavior. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. The relative density and the grain size increase with the increase of sintering time and temperature, and the sintering behavior is more sensitive to temperature than holding time. The mechanism controlling densification and grain growth at sintering temperature of 1550 °C is grain boundary diffusion. [ABSTRACT FROM AUTHOR]

This paper presents the results of the application of freeze granulation to the production of transparent neodymium-doped yttrium–aluminum garnet ceramics. Aqueous suspensions of aluminium oxide, yttrium oxide and neodymium oxide powders were prepared based on nanometric or submicronic powders which were either commercially available or prepared by precipitation. The relations between the composition of suspension, the properties of granulate and the final properties of ceramics (microstructure, optical transmission and emission spectra) were studied. [ABSTRACT FROM AUTHOR]

In this work, a comparative study of reactive sintering and optical properties of three laser composite transparent ceramics doped with neodymium: Nd:YAG/Nd:YS 1 AG, Nd:YAG/Nd:LuAG and Nd:YS 1 AG/Nd:LuAG has been achieved. Samples were manufactured thanks to pressureless co-sintering under vacuum of bilayer powder compacts. The reaction sequence from primary oxides to final garnet phases has been investigated. Similar dilatometric behavior was observed during reactive-sintering for each composition. Differential shrinkage can be thus accommodated to some extent. Second, this work has shown that the intermediate zone at composites interface is composed of single-phased garnet solid-solution with continuous evolution from one side to the other. The thickness of the interdiffusion zone was found to be limited to about 100 μm in all cases and appeared to be well described by classical diffusion laws of Fick and Whipple-Le Claire. The analyses of spectroscopic properties of transparent ceramics composites have finally shown that composite ceramics should be suitable to produce dual wavelength emission for terahertz generation. [ABSTRACT FROM AUTHOR]

A novel procedure for constructing mesoporous Nd 2 O 3 /TiO 2 nanocomposites with different Nd 2 O 3 (0.5–2%) was performed utilizing a soft template and impregnation method. Aqueous solutions of ciprofloxacin (CIP) as a pollutant antibiotics model were utilized to estimate the photocatalytic ability of the mesoporous Nd 2 O 3 /TiO 2 nanocomposites under visible exposure. The Nd 2 O 3 /TiO 2 nanocomposites displayed promoted photocatalytic ability for CIP degradation compared with TiO 2 NPs, with a maximum degradation of 100% over 1.5%Nd 2 O 3 /TiO 2 nanocomposite during 150 min illumination time, which is almost eight folds greater than TiO 2 NPs. The apparent rate constant of 1.5% Nd 2 O 3 /TiO 2 nanocomposite exhibited 11.8 times larger than TiO 2 NPs. The promotion of photocatalytic ability over Nd 2 O 3 /TiO 2 nanocomposites was ascribed to the combination between Nd 2 O 3 and TiO 2 , leading to enhanced formation of the •OH and •O 2 − accountable for CIP decomposition. The introduction of Nd 2 O 3 into TiO 2 was promoted transportation and separation of charge carriers. The Nd 2 O 3 /TiO 2 photocatalysts exhibited good corrosive resistance and mechanical stability after five consecutive runs of CIP degradation. The photocatalytic performances and mechanism over Nd 2 O 3 /TiO 2 nanocomposites were verified utilizing photoluminescence and photocurrent density measurements. The prepared mesoporous Nd 2 O 3 /TiO 2 nanocomposites are promising for environmental remediation. [Display omitted] • Constructing mesoporous Nd2O3/TiO2 was achieved utilizing a soft template. • Ciprofloxacin (CIP) as a pollutant was utilized to estimate the photocatalytic ability. • Nd2O3/TiO2 displayed maximum degradation of 100% after 150 min illumination time. • The rate constant of 1.5% Nd2O3/TiO2 exhibited 11.8 times larger than TiO2 NPs. • Nd2O3/TiO2 exhibited good corrosive resistance and high stability after five runs. [ABSTRACT FROM AUTHOR]

A novel binuclear neodymium complex Nd(CF 3 COO) 3 ·(Ph 3 PO) 2 (Ph 3 PO: triphenylphosphine oxide) with high stimulated emission cross-section was presented. The molecular structure of the complex was characterized by single-crystal X-ray diffraction. The optical properties of the complex in liquid medium were studied. From the absorption and luminescence spectra, the Judd–Ofelt parameters of Nd(CF 3 COO) 3 ·(Ph 3 PO) 2 in phosphorus oxychloride were obtained. Based on the crystal structure, the effects of crystal field and bonding valence properties on three intensity parameters Ω t ( t = 2, 4, 6) and emission cross-section were analyzed in detail. The emission cross-section of 4 F 3/2 → 4 I 11/2 fluorescence transition (2.78 × 10 −20 cm 2 ) of the new neodymium compound was higher than those of other Nd(III) complexes and even comparable with some laser glasses. [ABSTRACT FROM AUTHOR]

Oleic acid (OA)-modified LaF 3 :Nd, NaYF 4 :Nd and CaF 2 :Nd nanocrystals (NCs) with the different Nd 3+ ion concentration (2% and 5%) have been prepared. The structure and morphology of NCs were identified by XRD, TEM, FT-IR and TGA. The size of OA-modified NC is a mean diameter of 5–10 nm and can be dispersed in common organic solvents to form a transparent solution. The optical loss of NCs in organic solvent is the first time to discuss in this work. The luminescence properties of NCs were also characterized and studied by fluorescence spectrometer. The nanoparticles in solid and in the solution all exhibited the strong emission at the 1060 nm when the materials were excited around 800 nm. Compared with the LaF 3 and CaF 2 matrix, NaYF 4 as the host can protect the Nd 3+ ions more efficiently away from the nonradiative transitions. The longest luminescent lifetime of the solid NaYF 4 :2%Nd NCs was up to 136 μs, and the little difference of the fluorescence lifetime existed between the NCs in solid state and in solution. The low optical loss in organic solvent indicated that the Nd 3+ ions-doped fluoride NCs are promising materials for optical amplification fields. [ABSTRACT FROM AUTHOR]

TiO 2 and TiO 2 :Nd thin films were deposited using reactive magnetron sputtering process from mosaic Ti–Nd targets with various Nd concentration. The thin films were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and spectroscopic techniques. Photoluminescence (PL) in the near infrared obtained upon 514.5 nm excitation was also examined. The relationship between the Nd concentration, structural, optical and photoluminescence properties of prepared thin films was investigated and discussed. XRD and TEM measurements showed that an increase in the Nd concentration in the thin films hinders the crystal growth in the deposited coatings. Depending on the Nd amount in the thin films, TiO 2 with the rutile, mixed rutile–amorphous or amorphous phase was obtained. Transmittance measurements revealed that addition of Nd dopant to titania matrix did not deteriorate optical transparency of the coatings, however it influenced on the position of the fundamental absorption edge and therefore on the width of optical band gap energy. All TiO 2 :Nd thin films exhibited PL emission that occurred at ca. 0.91, 1.09 and 1.38 μm. Finally, results obtained for deposited coatings showed that titania with the rutile structure and 1.0 at.% of Nd was the most efficient in VIS to NIR photon conversion. [ABSTRACT FROM AUTHOR]

Spectroscopic parameters of a novel Nd 3+ -activated barium borate (BBONd) glass have been analyzed for broadband laser amplification. The Judd–Ofelt (JO) intensity parameters were determined through a systematic analysis of the absorption spectrum of Nd 3+ ions in the BBONd glass. High values of the JO intensity parameters reveal a great centro-symmetrical loss of the Nd 3+ sites and high covalency degree of the ligand field. The very high Ω 6 intensity parameter value makes evident both a great structural distortion of the Nd 3+ sites and a strong electron–phonon coupling between Nd 3+ and free OH − ions, which is consistent with the phonon energy maximum (3442.1 cm −1 ) recorded by Raman spectroscopy. This strong electron–phonon coupling favors high effective bandwidth and gain bandwidth values of the laser emission ( 4 F 3/2 → 4 I 11/2 ) of Nd 3+ ions. The electric-dipole oscillator strengths of all the Nd 3+ absorption transitions, and in particular that of the hypersensitive transition ( 4 I 9/2 → 4 G 5/2 ), are enhanced by this great structural distortion of the host. Broadband laser amplification of the 4 F 3/2 → 4 I 11/2 emission (1062 nm) of Nd 3+ ions in the BBONd glass pumped at 805 nm ( 4 I 9/2 → 4 F 5/2 + 2 H 9/2 ) is evaluated through the main fluorescent parameters in competition with non-radiative processes. In general, the BBONd glass exhibits spectroscopic parameters comparable with those reported in the literature for broadband laser amplification into the IR region. [ABSTRACT FROM AUTHOR]

The excited state dynamics and near-infrared (IR) luminescent properties of Nd 3+ -doped melt-quenched aluminophosphate glass containing silver and tin have been investigated under pulsed-laser and steady-state excitation at 266 nm. A comparative emission dynamics assessment was carried out concerning Ag and Sn dopants in the glass matrix with and without neodymium. The data indicates an effective non-radiative energy transfer from single Ag + ions and Sn centers as donors to neodymium activator ions which ultimately populates the 4 F 3/2 emitting state in Nd 3+ . As a result, the near-IR (1.06 μm) emission from the 4 F 3/2 metastable state in Nd 3+ is enhanced about an order of magnitude relative to a purely Nd-doped reference. In addition, the 4 F 3/2 excited state lifetime becomes significantly longer in the presence of silver and tin. A comparative 31 P nuclear magnetic resonance spectroscopy study suggests glass depolymerization upon neodymium doping. It is proposed that a structural alteration might be linked to the established non-radiative energy transfer. [ABSTRACT FROM AUTHOR]

A self-activated crystal Na 2 Nd 2 O(BO 3 ) 2 has been grown from the Na 2 O–Nd 2 O 3 –B 2 O 3 –NaF system. Its structure was determined by single crystal X-ray diffraction, and verified by infrared spectrum and inductively coupled plasma optical emission spectrometry. Na 2 Nd 2 O(BO 3 ) 2 crystallizes in the monoclinic crystal system, space group P 2 1 / c with unit-cell parameters a = 10.804 Å, b = 6.421 Å, c = 10.450 Å, β = 117.95°, Z = 4, and V = 640.4 Å 3 . Its absorption and emission spectra were measured at room temperature. Based on the absorption spectrum, the spontaneous transition probabilities, fluorescence branch ratio, and the radiation lifetime of 4 F 3/2 state were calculated. The emission properties under the 355 nm excitation were also evaluated. The electronic structure of Na 2 Nd 2 O(BO 3 ) 2 was calculated by the first-principles method. The obtained results show that Na 2 Nd 2 O(BO 3 ) 2 may be a promising microchip laser material. [ABSTRACT FROM AUTHOR]