Absorption Of Nd Research Articles

Nd Recovery from Wastewater with Magnetic Calcium Alginate ((1,4)-β-d-Mannuronic Acid and α-L-Guluronic Acid) Hydrogels.

In this study, a magnetic adsorbent material was produced, by environmentally friendly and inexpensive precursor materials, to clean wastewater that may result from primary and secondary rare earth metal (REM) production. Then, the absorption of Nd3+ ions from wastewater was done and this process's kinetic and isotherm models were developed. Thus, the removal of Nd3+ from wastewater with magnetic materials was accomplished, and then, this precious metal was recovered by using different acid media. First, Fe sub-micron particles were successfully produced by the polyol method. To increase the stability of Fe-based particles, their surfaces were covered with an oxide layer, and the average thickness was determined as 16 nm. The synthesized Fe particles were added into the calcium alginate beads and then coated with chitosan to increase the pH stability of the gels. The chemical composition of the gels was determined by Fourier transform infrared spectroscopy, the thermal properties were determined by differential scanning calorimetry, and the magnetic properties were determined by vibrating-sample magnetometer analysis. The magnetic saturation of the hydrogels was 0.297 emu/g. After the production of magnetic calcium alginate hydrogels, Nd3+ ion removal from wastewater was done. Wastewater was cleaned with 94.22% efficiency. The kinetic models of the adsorption study were derived, and isotherm studies were done. Adsorption reaction fitted different kinetic models at different time intervals and the Freundlich isotherm model. The effect of pH, temperature, and solid-liquid ratio on the system was determined and the thermodynamic constants of the system were calculated. After the adsorption studies, Nd3+ ions were regenerated in different acid environments and achieved an 87.48% efficiency value. The removal of Nd3+ ions from wastewater was carried out with high efficiency, the gels obtained as a result of adsorption were regenerated with high efficiency by using acid media, and it was predicted that the gels could be reused. This study is thought to have reference results not only for the removal of REM from wastewater by magnetic adsorption materials but also for the adsorption of heavy metals from wastewater.

Growth and luminescence properties of Nd,Cr:YSAG crystal

ABSTRACT In this study, 0.5 at% Cr3+ and 1 at% Nd3+ co-doped YSAG (Nd,Cr:YSAG) single crystal was grown by the Czochralski technique. The crystal structure is characterised with X-ray diffraction method. Compared with the absorption of Nd:YSAG crystal, two broad and intense absorption bands are observed in visible region of Nd,Cr:YSAG crystal, which are corresponding to the transitions of Cr3+ from ground state 4A2 to excited states 4T1 and 4T2, respectively. Using visible lights excitation (459 nm and 589 nm), the emission intensity of Nd,Cr:YSAG crystal is much stronger than that of Nd:YSAG crystal. The energy transfer mechanism from Cr3+ to Nd3+ ions in YSAG crystal is analysed. All the results indicate that Nd,Cr:YSAG is a promising high efficient 1 μm laser crystal suitable for solar or flash lamp pumping.

Mid-infrared spectroscopy of Nd:YLF crystal

Although well known for its near infrared emission, Nd:YLF is far less studied in the mid-infrared range (MIR). In this work, the polarized stimulated emission cross section of the decay to the 4I15/2, at around 2 μm and the branching ratios of all the radiative decay channels from 4F3/2 to the lower levels, have been estimated by applying the beta-tau method. Moreover, the absorption of Nd:YLF crystal has been measured from the near infrared up to the crystal absorption edge of the spectrum in MIR. Finally, the emission from the first excited state to the sublevels of the ground state in mid infrared at around 4.9 and 5.9 μm have been observed and discussed.

Nd3+:YAG transparent ceramics sintered under atmospheric pressure for improving the color gamut of LED-lit LCD

In order to improve the color gamut of white light emitting diodes (wLEDs) for LCD backlights, Nd 3+ -doped YAG transparent ceramics were used as the color filters to provide pure green and red colors to improve the color gamut. The Nd 3+ :YAG transparent ceramic color filters were prepared by the solid-state reaction method. Compared with the glass filter and the phosphor-in-glass filter, Nd 3+ :YAG transparent ceramics have better heat dissipation capacity. Moreover, Nd 3+ :YAG and Ce 3+ :YAG transparent ceramics are of the same host materials, therefore the refractive index of them is almost the same, and the light loss at the interface is expected to be negligible. The wLED prototypes fabricated by stacking a blue LED chip with the Ce 3+ :YAG ceramic phosphor plate and the Nd 3+ :YAG transparent ceramic filter, due to the sharp and strong absorption of Nd 3+ : 4 I 9/2 → 4 G 5/2 , 2 G 7/2 transition, the color gamut of the light source prototype has been increased from 77.36% to 86.79%, which indicated that it may have a promising prospect in improving the color gamut of wLEDs for LCD backlight displays. • Nd 3+ :YAG ceramics were prepared by sintering in oxygen under atmospheric pressure. • The Nd 3+ :YAG transparent ceramic showed high thermal conductivity. • Nd 3+ :YAG ceramic used for filtering can increase the color gamut by 9.43% NTSC standard.

Evaluation of Separating Process for Different Materials by Thermal Stress Cleaving Technique

This paper aims to evaluate the separating process of brittle materials by thermal stress cleaving technique. This process is suitable for separating thin brittle materials such as sapphire and silicon wafer, which are sensitive to force. Both materials were used largely in microelectronics, solar cells and micro-mechanical industries that require precise machining. Finite element method was used to evaluate a steady state thermal stress by considering the temperature transient during laser irradiation process. The heat source was assigned according to the laser energy absorption characteristics of the materials. Stress intensity factor was analyzed to determine the starts of separation process. The results show that CO2 laser energy was absorbed on the surface of the sapphire material as compared proportionated absorption of Nd:YAG laser energy on silicon material. Due to thermal stress generated by the laser beam, material separation was start. Fracture begins at the bottom surface of sapphire wafer compared to fracture initiation at the prepared groove for silicon wafer. The material separation can be controlled when it begins at the groove. Hence, better surface finished can be achieved.

Nd:YAG laser combined with gold nanorods for potential application in port-wine stains: an in vivo study.

Neodymium:yttrium aluminum garnet (Nd:YAG) lasers exhibit considerable potential for treating deeply buried port-wine stains. However, the application of Nd:YAG laser is limited by its weak absorption to blood. This in vivo study tested the efficacy and safety of utilizing thiol-terminated methoxypolyethylene glycol-modified gold nanorods (PEG-GNRs) to enhance the absorption of Nd:YAG laser to blood. Mouse mesentery and dorsal skinfold chamber (DSC) model were prepared to analyze the thermal responses of a single venule without anatomic structures, as well as blood vessels in the complex structure of the skin, to laser light. After the injection of 0.44mg of PEG-GNRs, the required threshold density of laser energy for blood coagulation and complete vasoconstriction decreased from 24 to 18 J/cm2 in the mesentery model and from 36 to 31 J/cm2 in the DSC model. The laser pulse required for blood coagulation and complete vasoconstriction decreased by 67.75% and 62.25% on average in the mesentery model and by 67.55% and 54.45% on average in the DSC model. Histological and histochemical results confirmed that PEG-GNRs are nontoxic in the entire mouse life span. Therefore, combining PEG-GNRs with Nd:YAG laser may be effective and safe for inducing an obvious thermal response of blood vessels under low energy density and minimal pulse conditions.

Highly Emissive Dye-Sensitized Upconversion Nanostructure for Dual-Photosensitizer Photodynamic Therapy and Bioimaging.

Rare-earth-based upconversion nanotechnology has recently shown great promise for photodynamic therapy (PDT). However, the NIR-induced PDT is greatly restricted by overheating issues on normal bodies and low yields of reactive oxygen species (ROS, 1O2). Here, IR-808-sensitized upconversion nanoparticles (NaGdF4:Yb,Er@NaGdF4:Nd,Yb) were combined with mesoporous silica, which has Ce6 (red-light-excited photosensitizer) and MC540 (green-light-excited photosensitizer) loaded inside through covalent bond and electrostatic interaction, respectively. When irradiated by tissue-penetrable 808 nm light, the IR-808 greatly absorb 808 nm photons and then emit a broadband peak which overlaps perfectly with the absorption of Nd3+ and Yb3+. Thereafter, the Nd3+/Yb3+ incorporated shell synergistically captures the emitted NIR photons to illuminate NaGdF4:Yb,Er zone and then radiate ultrabright green and red emissions. The visible emissions simultaneously activate the dual-photosensitizer to produce a large amount of ROS and, importantly, low heating effects. The in vitro and in vivo experiments indicate that the dual-photosensitizer nanostructure has trimodal (UCL/CT/MRI) imaging functions and high anticancer effectiveness, suggesting its potential clinical application as an imaging-guided PDT technique.

Nd:YAG laser-induced morphology change and photothermal conversion of gold nanorods with potential application in the treatment of port-wine stain.

Based on the principle of selective photothermolysis, 1064nm Nd:YAG laser has great potential for the treatment of deeper and larger PWS. However, the clinical effectiveness is limited because of the weak absorption of blood to Nd:YAG laser. The aim of this study is to obtain the optimal irradiation conditions to effectively destroy vascular lesions with the assistance of PEG-modified gold NRs to enhance blood absorption of Nd:YAG laser. In our study, PEG-modified gold NRs were prepared by the seeded growth method. Gold NRs after exposure to Nd:YAG laser were characterized using absorption spectra and transmission electron microscope images. The tissue-like phantom containing a glass capillary with blood was prepared and exposed to Nd:YAG laser to investigate the laser energy density and pulse number required for blood coagulation before and after the addition of gold NRs in blood. The results show that the millisecond Nd:YAG laser irradiation does not result in the shape change of gold NRs. After injection of gold NRs into the bloodstream (4.60mg/kg), the absorbance of blood at 1064nm increased 3.9 times. The threshold energy density for the treatment of PWS decreased by 33% (from 30 to 20J/cm2). Our findings provide an experimental guide for choosing laser parameters and gold NRs concentration for the treatment of deeper and larger PWS with the assistance of PEG-modified gold NRs in vivo in the future.

The effect of repeated laser stimuli to ink-marked skin on skin temperature-recommendations for a safe experimental protocol in humans.

Background. Nd:YAP laser is widely used to investigate the nociceptive and pain systems, generating perpetual and laser-evoked neurophysiological responses. A major procedural concern for the use of Nd:YAP laser stimuli in experimental research is the risk of skin damage. The absorption of Nd:YAP laser stimuli is greater in darker skin, or in pale skin that has been darkened with ink, prompting some ethics boards to refuse approval to experimenters wishing to track stimulus location by marking the skin with ink. Some research questions, however, require laser stimuli to be delivered at particular locations or within particular zones, a requirement that is very difficult to achieve if marking the skin is not possible. We thoroughly searched the literature for experimental evidence and protocol recommendations for safe delivery of Nd:YAP laser stimuli over marked skin, but found nothing.Methods. We designed an experimental protocol to define safe parameters for the use of Nd:YAP laser stimuli over skin that has been marked with black dots, and used thermal imaging to assess the safety of the procedure at the forearm and the back.Results. Using thermal imaging and repeated laser stimulation to ink-marked skin, we demonstrated that skin temperature did not increase progressively across the course of the experiment, and that the small change in temperature seen at the forearm was reversed during the rest periods between blocks. Furthermore, no participant experienced skin damage due to the procedure.Conclusion. This protocol offers parameters for safe, confident and effective experimentation using repeated Nd:YAP laser on skin marked with ink, thus paving the way for investigations that depend on it.

Visible-Light-Induced Photocatalytic Removal of Aqueous Nitrate with Nd, N-Codoped Titania Nanoparticles

An enhanced and selective nitrate reduction by neodymium (Nd), N-codoped TiO2 under visible light irradiation was reported in this study. A series of Nd, N-codoped TiO2 nanoparticles with varying amounts of neodymium were synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N-2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), UV-vis absorbance spectroscopy, and photoluminescence spectra. Homogeneously dispersed Nd species can inhibit the growth of TiO2 particles, increase the surface area of codoped TiO2, prolong the lifetime of photogenerated electrons, and act as efficient reduction sites for nitrate. Among the hole scavengers studied, formic acid was found to be the most effective for nitrate reduction with 85% N-2 selectivity. The hole scavenger quantity also affected its reduction efficiency and product selectivity. Both the nitrate reduction and N-2 selectivity of Nd, N-codoped TiO2 were higher than those of N-doped TiO2 alone. The codoped TiO2 with 1.0% neodymium showed the highest surface area, most nitrate dark adsorption, and the best photocatalytic activity under visible light irradiation. Enhanced nitrate conversion and N-2 selectivity can be attributed to the synergistic effect of the optimal Nd concentration, high surface area, and appreciable visible light absorption of Nd, N-codoped TiO2.

Graphite Application and Different Powers of Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) Laser on Dentin Surface Changes: A Scanning Electron Microscopy Study

Introduction: Various methods have been used for the treatment of dentine hypersensitivity such as dentifrices, sealants and different types of lasers. The aim of this study was to evaluate the effect of Neodimium:Yttrium-Aluminium-Garnet (Nd:YAG) laser in association with graphite on the dentin morphologic changes. Methods: In this experimental in vitro study, 16 freshly extracted third molars were selected. 5 specimens with the dimensions of 2×2×1 mm from root trunk were prepared. Specimens were randomly divided into five groups: group 1 (control, no laser irradiation). Group 2, 3 irradiated by Nd:YAG laser 0.5 and 1W, output power respectively. Group 4, 5 smeared with graphite and then irradiated by Nd: YAG laser 0.5 and 1W output power. Samples were prepared for scanning electron microscopy. Number and diameter of dentinal tubules were determined in different groups and analyzed with the Kruskal-wallis and Mann-Whitney tests (SPSS 16). Results: The number of tubules had significant difference between all groups (P 0.05), and group 3 in comparison with group 4 (P> 0.05). Micro-cracks and rupture of melted dentin materials were seen in group 4 and 5. Conclusion: According to the findings of this study, smearing with graphite on dentin surface increase the absorption of Nd:YAG laser energy and reduced the diameter and number of open dentinal tubules.

Effects of crystal parameters on power and efficiency of Nd : YVO4 laser in-band pumped by 914 nm laser

To overcome the main drawback of poor pump absorption of Nd : YVO4 lasers in-band pumped at 914 nm, three possible methods of higher temperature, longer crystal length and higher doping concentration were experimentally studied. A Nd : YVO4 laser operating at 914 nm was used as high beam quality, narrow line-width pump source to make the measurement of pump absorption accurate. Four different Nd : YVO4 crystals were used as gain mediums to investigate the effects of crystal parameters. We found that heating the crystal effects differently on output power and overall efficiency when crystal doping concentration changed. To improve the pump absorption and meanwhile achieve high efficiency, longer crystal with proper doping concentration and pump feedback should be adopted instead of highly doped crystal.

High pressure luminescence and time resolved spectra of LiNbO3:Pr3+

Emission, luminescence excitation spectra and photoluminescence spectra at high pressure of LiNbO 3 crystal doped with 0.5% Pr 3+ are presented. Hydrostatic pressure up to 135kbar was applied with a diamond anvil cell (DAC). We observed the small red shift of the luminescence related to 1 D 2 → 3 H 4 transition equal to 0.08nm/kbar. Additionally, at higher pressure, the 1 D 2 emission was considerably quenched and its lifetime was shortened. This was explained as being due to the decrease of the energy of the exciton bound to the Pr 3+ ion with increasing pressure and nonradiative depopulation of the 1 D 2 state. Full Text: PDF References H. Laro, M. Voda, F. Jaque, J.E. Munoz-Santiuste, J. Garcia-Sole, "Polarized absorption of Nd 3+ in LiNbO 3 : Effect of MgO codoping", J. Appl. Phys. 77, 5929 (1995) [CrossRef] A. Lorenzo, L.E. Bausa, J. Garcia-Sole, "Optical spectroscopy of Pr 3+ ions in LiNbO 3 ", Phys. Rev. B. 51, 16643 (1995) [CrossRef] A. Lorenzo, E. Camarllo, H.S. Maurrieta, S. Alvarez, V.G. Hemandez, M. Voda, F. Jaque, J. Garcia-Sole, "Optical spectroscopy of Dy 3+ ions in LiNbO 3 ", Opt. Matter. 5, 251 (1996) [CrossRef] M. Malinowski, P. Myziak, R. Piramidowicz, I. Pracka, T. Łukasiewicz, B. Surma, S. Kaczmarek, K. Kopczyński, Z. Mierczyk, "Spectroscopic and laser properties of LiNbO 3 :Dy 3+ crystals", Acta Phys. Pol. 90, 181 (1996) A. Lorenzo, L.E. Bausa, J.A. Sanz, J. Garcia-Sole, "Optical absorption intensities and fluorescence dynamics of Ho 3+ ions in LiNbO 3 ", J. Phys.: Cond. Matter 8, 5781 (1996) [CrossRef] J. Amin, B. Dusardier, T. Schweizer, M. Hempsead, "Spectroscopic analysis of Er 3+ transitions in lithium niobate", J. Lumin. 69,17 (1966) [CrossRef] L. Nunez F. Cusso, "Polarized absorption and energy levels of LiNbO 3 :Tm and LiNbO 3 (MgO):Tm", J. Phys.: Cond. Matter. 5, 5301 (1993) [CrossRef] Z. Łuczyński, T. Łukasiewicz, I. Pracka, B. Surma, M. Malinowski, "Emission properties of LiNbO 3 :Tm 3+ ", J. Appl. Spectr. 62, 66 (1995) A. Lorenzo, H. Jaffrezic, B. Roux, G. Boulon, L.E. Bausia, J. Garcia-Sole, "Lattice location of Pr3+ ions in LiNbO 3 ", Phys. Rev. B 52, 6278 (1995) [CrossRef] R. Piramidowicz, I. Pracka, W. Woliński, M. Malinowski, "Blue-green emission of Pr 3+ ions in LiNbO 3 ", J. Phys.:Cond Matter 12, 709 (2000) [CrossRef] J.E. Munoz-Santiuste, A. Lorenzo, L.E. Bausa, J. Garcia-Sole, "Crystal field and energy levels of Pr 3+ centres in LiNbB 3 ", J. Phys.: Cond Matter 10, 7653 (1998) [CrossRef] D.S. McClure, C. Pedrini, "Excitons trapped at impurity centers in highly ionic crystals", Phys. Rev. B 32, 8465 (1985) [CrossRef] W. Gryk, B. Kukliński, M. Grinberg, M. Malinowski, "High pressure spectroscopy of Pr 3+ in LiNbO 3 ", J. Alloy. Comp. 380, 230 (2004) [CrossRef] W. Gryk, D. Dyl, M. Grinberg, M. Malinowski, "High pressure photoluminescence study of Pr 3+ doped LiNbO 3 crystal", Phys. Stat. Sol. C 2, 188 (2005) [CrossRef]

Spectroscopic properties of Er doped and Er, Nd codoped fluoride glasses under simulated sunlight illumination

We investigated the fluorescence characteristics of Er codoped Nd doped ZBLAN glasses proposed for solar pumped fiber laser (SPFL) under simulated sunlight. Er is used as a sensitizer because it absorbs a part of the ultraviolet and visible light where is no absorption of Nd. Under simulated sunlight illumination, Er singly doped fluoride glass displayed four emission bands with peaks at 550, 848, 977 and 1533 nm attributed to the 4S 3/2- 4I 15/2, 4S 3/2- 4I 13/2, 4I 11/2- 4I 15/2 and 4I 13/2- 4I 15/2 electronic transitions of Er, respectively. The quantum efficiency measurement was carried out using an integrating sphere and under the simulated sunlight excitation showed a maximum of 73% for 0.5 mol.% of ErF 3 in ZBLAN glass. In Nd, Er codoped fluoride glass, the 1.05 μm emission of Nd was observed under 380 nm excitation what supposes the energy transfer from Er to Nd in ZBLAN glasses as Nd has no absorption at the wavelength. Er, Nd codoped fluoride glasses are promising as a sensitized laser media for solar pumped fiber lasers.

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.

Investigation on Welding Phenomenon for Aluminum Alloy by Superposition of Pulsed YAG Laser and Diode Laser

A pulsed Nd:YAG laser and a continuous diode laser were spatially superposed for higher absorption of laser beam to aluminum alloy. 12-20% increase in the bead width and 15-30% increase in the weld depth could be obtained by the superposition of continuous diode laser and pulsed Nd:YAG laser. Moreover, the unsteady thermal analysis with a key-hole effect indicated that the temperature of specimen surface with a continuous diode laser could be kept approximately 300K higher than that without a continuous diode laser. Therefore, it was clarified that the bead width and depth would increase greatly due to higher absorption of Nd:YAG laser to aluminum alloy by the superposition of a continuous diode laser.

Wavelength translation based on photoinduced broadband absorption in Nd^3+-doped lanthanum lead zirconate titanate ceramics

A correlation between a photoinduced broadband absorption (BBA) and a strong long persistent optoenergy storage (LPOES), both evident in ceramic plates of neodymium-doped lanthanum-modified lead zirconate titanate (Nd:PLZT), has been proposed and verified experimentally. As a direct evidence of the suggested correlation, a 3.0 dB gain was obtained with a preilluminated Nd:PLZT plate by simply heating up the plate to 60 degrees C. Thermal history related gain profiles taken in an Nd:PLZT plate unveiled that the intrinsically rich carrier traps in the ceramics are highly responsible for the remarkable BBA and underlying LPOES, and hence thermal to near-IR wavelength translation.

Substrate role in the accumulation of heavy metals in sporocarps of wild fungi

The distribution of neodymium, lead, thorium and uranium was investigated in about 100 samples of 12 different species of common, edible and non-edible mushrooms collected in unpolluted areas in the province of Ciudad Real, Central Spain. The quantitative analysis of heavy metals was performed by X-ray fluorescence spectrometry (a simple, accurate and non-destructive method). The concentration of these elements was related to three factors: mushroom specie, life style/substrate and study area. The results reveal considerable amounts of the four metals in all species analyzed as well as significant differences on the capability to accumulate these elements. The maximum absorption of Nd and Pb was found in the ectomycorrhizal Cantharellus cibarius, reaching values of 7.10 and 4.86 microg g(-1), respectively. Thorium and uranium were mainly accumulated (3.63 and 4.13 microg g(-1), respectively) in Hypholoma fasciculare although it is an epiphyte species, isolated from the mineral particles of soil. The distribution patterns of these metals in sporocarps of different habitats and locations showed no significant differences, except for thorium, mainly accumulated in mushrooms living on wood regarding these living on soil organic matter. The species-specific is therefore the determining factor for accumulation of Nd, Pb, Th and U, more than substrate, in this study.

Large H Absorption in Nd2Ni2In; Magnetism in a New Structure Type

AbstractSeveral hydrides of Nd2Ni2In with various H concentrations up to 6 H atoms/f.u. have been synthesized. Nd2Ni2In crystallizes in the tetragonal Mo2FeB2 structure type which can be changed upon hydrogenation to an orthorhombic structure, space group Pbma. The unit-cell volume increases by 15.5 % for Nd2Ni2InH4.5 and by 21.6 % for Nd2Ni2InH6. The triangular rare-earth lattice can give rise to magnetic frustration in case of antiferromagnetic interactions in Nd2Ni2In. The frustration is removed upon hydrogenation due to the orthorhombic distortion. The magnetic ordering temperature decreases with H concentration from 8 K in Nd2Ni2In down to 3.5 K in Nd2Ni2InH6.

Crystal growth and optical performance of Nd:Sr3Ga2Ge4O14 crystals

AbstractNd:Sr3Ga2Ge4O14 (Nd:SGG) single crystals up to ∅︁25 mm × 50 mm were grown by the modified Bridgman method. Absorption and fluorescence spectra of Nd:SGG crystals were measured at room temperature. Compared with Nd:YAG crystals, the absorption of Nd:SGG single crystals presented broad absorption bands of Nd3+ ions. The fluorescence inten‐ sity increased with Nd concentration while the fluorescence lifetime of the 4F3/2–4I11/2 transition excited by a diode laser at room temperature showed a slight decrease when the Nd concentration increased to 8 at%. The results indicated that the quenching effect might occur in Nd:SGG crystals doped with higher Nd concentrations. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)