Xiaoxia Cui

Luminescence properties of Nd3+-doped LaF3 nanocrystals with a long lifetime in organic solvents

A kind of monodisperse LaF3:Nd nanocrystal with a small size and long lifetime in solvent was synthesized via a hydrothermal process. The crystalline phase, morphology, and luminescence properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), emission spectroscopy as well as dynamic decays. The results indicated that LaF3:Nd nanocrystals with a size below 30 nm have great dispersity in various solvents. An excellent lifetime of 359 μs was detected in a transparent DMSO–tetrabromoethane dispersion. It suggested that these nanocrystals could have great applications in biological and optical amplification fields.

400 mW narrow-linewidth Tm-doped silica fiber laser output near 1750 nm with volume Bragg grating.

A type of Tm-doped silica fiber laser with narrow-linewidth and output wavelength near 1750 nm was firstly presented, by using a 1550 nm Er-doped fiber laser pump source and a volume Bragg grating (VBG). By means of a 15 cm Tm-doped fiber, a 400 mW continuous wave (cw) at ~1750 nm with FWHW of ~54 pm was generated, corresponding to an average slope efficiency up to 23.5% with respect to absorbed pump power. The influence of gain fiber length on the spectrum wavelength has been investigated in detail. All experimental results demonstrate that this fiber laser will be an effective and promising pump source for mid-IR laser output.

Flux-solvothermal preparation of dispersible LiLa0.4Nd0.6(PO3)4 microcrystals with regular morphology and superior fluorescence

A flux-solvothermal method was used to grow a type of novel dispersible LiLa0.4Nd0.6(PO3)4 microcrystals with high Nd3+ ions concentration of 2.63 × 1021 cm−3 and excellent fluorescence properties for the first time. By optimizing experimental conditions, microcrystals with sizes in the region of 1.5–5 μm, a strong emission intensity and long lifetime of 107 μs were obtained. The results show that their transparent dispersion in the mixed solvents of DMSO and CHBr2CHBr2 had a strong absorption at 800 nm, low solvent quenching ratio of 6.5%, high quantum yield of 32.17% and large emission cross section of 4.39 × 10−20 cm2 when the Nd3+ ions concentration is 1 × 1020 cm−3, which imply the microcrystals are of potential application in transparent glass-ceramics, dispersion amplifiers and lasers.

The damage property of oxyfluoride glasses irradiated by a 351 nm high fluence laser

The laser induced damage property of oxyfluoride glasses irradiated by a 351 nm laser has been investigated. Two kinds of oxyfluoride glass (oxyfluoride1 and oxyfluoride2) have been prepared by different preparation technologies and their LIDTs (laser induced damage thresholds) are 9.0 J cm(-2) and 13.6 J cm(-2) respectively. It is found that the variation of LIDT in oxyfluoride glasses is associated with photoluminescence originated structural defects. Decrease of the photoluminescence intensity in an oxyfluoride glass could improve the LIDT of the material. Meanwhile, an experiment on damage growth has been presented, and the damage growth of oxyfluoride glasses develops in the longitudinal direction of laser propagation, which causes the transmittance loss to be limited once the damage growth occurs. Moreover, the damage growth stops when the laser fluence is below 70% of the LIDT.

Morphology of NaNdF4 nanocrystals from Nd(C3H7COO)3·Phen and Nd(NO3)3·Phen (Phen, 1,10-phenanthroline) as neodymium precursors

A series of NaNdF4 nanocrystals was synthesized via a facile hydrothermal route with Nd(C3H7COO)(3)center dot Phen and Nd(NO3)(3)center dot Phen (Phen, 1,10-phenanthroline) as the Nd precursors. Distinct effect of the neutral donor ligand (Phen) on the morphology of NaNdF4 nanocrystals was demonstrated. When Nd(C3H7COO)(3)center dot Phen was chosen and the hydrothermal reaction temperature was controlled at 220 degrees C, the NaNdF4 nanocrystals with uniform short nanorod shape were obtained. The sizes of the as-prepared nanorods could be tuned by changing the hydrothermal temperatures. This method provided a useful way for the preparation of sodium rare-earth fluoride nanocrystals with controlled shapes and sizes.

A novel near-infrared nanomaterial with high quantum efficiency and its applications in real time in vivo imaging

Fluorescence imaging signal is severely limited by the quantum efficiency and emission wavelength. To overcome these challenges, novel NIR-emitting K5NdLi2F10 nanoparticles under NIR excitation was introduced as fluorescence imaging probe for the first time. The photostability of K5NdLi2F10 nanoparticles in the water, phosphate buffer saline, fetal bovine serum and living mice was investigated. The fluorescence signal was detected with depths of 3.5 and 2.0 cm in phantom and pork tissue, respectively. Fluorescence spectrum with a significant signal-to-background ratio of 10:1 was captured in living mice. Moreover, clear NIR images were virtualized for the living mice after intravenous injection. The imaging ability of nanoparticles in tumor-beard mice were evaluated, the enrichment of K5NdLi2F10 nanoparticles in tumor site due to the enhanced permeability and retention effect was confirmed. The systematic studies of toxicity, bio-distribution and in-vivo dynamic imaging suggest that these materials give high biocompatibility and low toxicity. These NIR-emitting nanoparticles with high quantum efficiency, high penetration and low toxicity might facilitate tumor identification in deep tissues more sensitively.

High Verdet constants and diamagnetic responses of GeS 2 -In 2 S 3 -PbI 2 chalcogenide glasses for integrated optics applications

Chalcogenide glasses as kind of diamagnetic magneto-optical materials have promising applications in the field of integrated optics and optical communication systems due to their excellent properties, such as easy to be processed into waveguide and temperature independence of the Verdet constants. For clarifying the influence factors following the compositional variation on Faraday effect and finding a glass with a large Verdet constant, novel pseudo-ternary chalcogenide glass system, GeS2 - In2S3 - PbI2, was prepared and investigated. The composition, wavelength and temperature dependences on the Verdet constants were systematically investigated at the wavelengths of 635, 808, 980 and 1319 nm. PbI2 was confirmed to have positive contribution to the Verdet constant and the Becquerel rule was proved to be an effective guidance for predicting the Verdet constant in chalcogenide glasses. The 60GeS2·15In2S3·25PbI2 glass was found to possess the largest Verdet constant (V = 0.215 min·G-1·cm-1, @808nm), which is great larger than that of commercial diamagnetic glasses. These glasses also possess good glass-forming ability and VIS-IR transmittance, therefore be a good candidate for next-generation integrated optical isolator and other magneto-optical devices.

Noninvasive blood glucose detection using a miniature wearable Raman spectroscopy system

In this Letter, a miniature wearable Raman spectroscopy system is developed. A wearable fiber-optic probe is employed to help the stable and convenient collection of Raman spectra. A nonlinear partial least squares model based on a multivariate dominant factor is employed to predict the glucose level. The mean coefficients of determination are 0.99, 0.893, and 0.844 for the glucose solution, laboratory rats, and human volunteers. The results demonstrate that a miniature wearable Raman spectroscopy system is feasible to achieve the noninvasive detection of human blood glucose and has important clinical application value in disease diagnosis.

Watts-level super-compact narrow-linewidth Tm-doped silica all-fiber laser near 1707 nm with fiber Bragg gratings

Watts-level ultra-short wavelength operation of a Tm-doped all fiber laser was developed by using a 1550 nm Er-doped fiber laser pump source and a pair of fiber Bragg gratings (FBGs). The laser yielded 1.28 W of continuous-wave output at 1707.01 nm with a narrow linewidth of ~44 pm by means of a 20 cm Tm-doped fiber. The dependencies of the slope efficiencies and pump threshold of the Tm-doped fiber laser versus the length of active fiber and reflectivity of the output mirror (FBG) were investigated in detail, in which the maximum average slope efficiency was 36.1%. There is no doubt that this all fiber laser will be a perfect pump source for mid-IR laser output.

Fundamental-frequency-absorbed oxyfluoride glass in a high-power laser

A high-power third-harmonic laser faces challenges in the filtering remnant unconverted fundamental frequency, which is from the frequency converting crystal. In this work, a novel fundamental-frequency-absorbed oxyfluoride glass has been prepared, which provides a possible option to solve the problem. By being doped with Fe2+ ion, the glass shows strong absorption property at 1053 nm, and the glasss transmittances at 351 and 1053 nm are stable with changing the laser power or increasing the irradiation times under high-power laser irradiation. Meanwhile, the laser-induced damage threshold of the glass is 12.5  J/cm2 at 351 nm, which is two times higher than that of fused silica whose threshold is 6.2  J/cm2 in the same testing condition. The glass also exhibits a higher laser-induced damage threshold as well as 36.6  J/cm2 at its absorption wavelength of 1053 nm. The results indicate that this glass is promising as a color-separation optic, thus allowing a novel design for the final optics assembly in an inertial confinement fusion laser system.