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115 results on '"Huang, Changbao"'

15. Growth and Device Fabrication of Mid to Far-Infrared Cr2+/Fe2+ :CdSe Crystals.

Author

HUANG Changbao, HU Qianqian, ZHU Zhicheng, LI Ya, MAO Changyu, XU Junjie, WU Haixin, and NI Youbao

Subjects
*NONLINEAR optical materials, *TRANSITION metal ions, *CRYSTALS, *SOLID-state lasers, *ABSORPTION coefficients, *ATOMIC absorption spectroscopy
Abstract

In this study, the Cr2+ :CdSe and Fe2+ :CdSe crystals were successfully grown by the Mo-crucible sealed Bridgman method using a vacuum single-crystal furnace with two zones developed by ourselves, and the crystal size reaches φ51 mm x 110 mm. Cr2+ :CdSe and Fe2+ :CdSe crystals demonstrate obvious absorption in the bands of 1 400 ~ 2 400 nm and 2 500 ~5 200 nm, respectively. The transmittances of Cr2+/Fe2+ doped CdSe crystals are close to the transmittance limit of CdSe crystal (~70%) in the 7 ~ 15 μm band, and the converted absorption coefficient is about 0.005 cm-1. The Cr2+/Fe2+ : CdSe crystals grown by the Mo-crucible sealed Bridgman method have the advantages of the controllable doping concentration of transition metal ions, uniform doping and high crystal quality. The Cr2+/Fe2+ : CdSe crystals could be used as both midinfrared laser crystal and far-infrared nonlinear optical crystal material. [ABSTRACT FROM AUTHOR]

Published
2024

20. Large-size high-quality CdSe-OPO component for far IR laser output prepared by directional crystal growth technique.

Author

Hu, Qianqian, Huang, Changbao, Wei, Lei, Wu, Haixin, Ni, Youbao, Yu, XueZhou, and Song, Yanan

Subjects
*CRYSTAL growth, *OPTICAL parametric oscillators, *MELTING points, *ABSORPTION coefficients, *LASERS
Abstract

CdSe crystals are one of the most potential far infrared (IR) nonlinear optical (NLO) materials due to their excellent overall performance. However, it is difficult to prepare a large-size and low absorption CdSe component, which limits laser output power. In this work, a CdSe crystal was grown using a capsuled Mo-crucible method to maintain a stoichiometric melt composition in the process of crystal growth. A high-quality CdSe crystal with the largest size to date of Φ40 × 100 mm3 along the (100) direction was successfully obtained using this method combined with a seed directional technique. The as-grown CdSe crystal demonstrated low absorption coefficients of <0.005 cm−1 at 2.05 μm and 10.6 μm, good crystallinity, and optical homogeneity. An 11 mm × 11 mm × 78 mm CdSe crystal element with = 73.5° ± 0.2°, and ϕ = 0° was fabricated to meet the requirement for type-II phase match (PM), the average idler output power of 1.8 W was obtained corresponding to a pulse energy of ∼0.36 mJ at 10.2 μm using signal-resonate optical parametric oscillator (SR-OPO) technology. Besides, the seed directional technique could provide reference for preparing other NLO crystals, and the capsuled Mo-crucible method could also be used to grow other chalcogenide crystals that have high melting points. [ABSTRACT FROM AUTHOR]

Published
2023
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28. Optical and defect properties of mid-IR laser crystal Dy3+: PbGa2S4: a DFT and XPS study.

Author

Yu, Xuezhou, Huang, Changbao, Ni, Youbao, Wang, Zhenyou, and Wu, Haixin

Subjects
*SOLID-state lasers, *ANNEALING of crystals, *OPTICAL properties, *CRYSTAL growth, *LIGHT absorption
Abstract

The Dy3+:PbGa2S4 crystal with low phonon energy has been used to achieve direct lasing of 4.3–4.7 μm lasers. High quality PbGa2S4 crystals are difficult to fabricate due to component volatilization. In this work, the influence of component condition on the intrinsic defects and optical absorption in the Dy3+:PbGa2S4 crystal was investigated through first-principles calculations and crystal growth experiments. We found that PbGa2S4 was prone to decompose into Ga2S3 at its growth temperature, usually resulting in PbS-rich (Ga2S3-deficient) growth conditions. The calculated results of defect formation energy indicate that the PbGa and VGa defects play a dominant role in PbGa2S4 under PbS-rich growth conditions. The Ga2S3-rich growth conditions can increase the defect formation energy and may lower the defect density. Our post-growth annealing and crystal growth experiments proved that the Ga2S3-rich conditions did improve the optical quality of the Dy3+:PbGa2S4 crystal. The structure and composition of PGS were analyzed by XRD and EDS. The XRC result showed the crystal has a high crystalline quality. The changes of bond length were studied through XPS characterization and DFT calculations. The VGa and PbGa defects result in different XPS peaks of PbGa2S4 crystals fabricated under PbS-rich and Ga2S3-rich growth conditions. [ABSTRACT FROM AUTHOR]

Published
2022
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32. Infrared Dielectric Properties Determination of Single Crystal Based on Transmission Spectrum of Polycrystalline Powder

Author

毛明生 Mao Mingsheng, 倪友保 Ni Youbao, 韩卫民 Han Weimin, 姜鹏飞 Jiang Pengfei, 王振友 Wang Zhenyou, 黄昌保 Huang Changbao, and 吴海信 Wu Haixin

Subjects
Materials science, Transmission (telecommunications), Infrared, business.industry, Spectrum (functional analysis), Optoelectronics, Crystallite, Dielectric, business, Single crystal, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials
Published
2020

37. Hyperamylasemia as an early predictor of mortality in patients with acute paraquat poisoning

Author

Huang, Changbao, Bai, Lina, Xue, Xiang, Peng, Liangfei, Jiang, Jinghan, and Zhang, Xigang

Abstract

Objective This study aimed to evaluate the relationship between elevated serum amylase levels and the prognosis of paraquat poisoning.Methods Patients were categorized into the elevated and non-elevated serum amylase groups according to serum amylase levels. Demographics, mortality, risk factors of elevated serum amylase levels, and injury to the pancreas were analyzed.Results A total of 457 patients were enrolled in this study and the overall mortality rate was 51.9%. Patients in the elevated group had worse indices than those in the non-elevated group. Kaplan–Meier survival analysis showed that the mortality rate in the elevated group was significantly higher than that in the non-elevated group (hazard ratio: 10.65, 95% confidence interval [CI]: 7.55–15.02). Multivariate Cox proportional hazards analysis showed that elevated serum amylase levels were related to mortality (hazard ratio: 2.066, 95% CI: 1.239–3.444). The receiver operating characteristic curve showed that the area under the curve was 0.724 (95% CI: 0.666–0.783) for serum amylase levels with 70.4% sensitivity and 74.0% specificity.Conclusion Elevated serum amylase levels are observed in PQ poisoning. This elevation might be one of the most accurate early prognostic factors for predicting severity and mortality.

Published
2024
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43. A Modified Vertical Bridgman Method for Growth of GaSe Single Crystal

Author

Ni Youbao, Cheng Xu-Dong, Wu Haixin, Xiao Rui-Chun, Wang Zhenyou, and Huang Changbao

Subjects
Range (particle radiation), Materials science, Birefringence, business.industry, Infrared, Analytical chemistry, Laser, Spectral line, law.invention, Inorganic Chemistry, Crystallinity, Optics, law, Attenuation coefficient, General Materials Science, business, Single crystal
Abstract

As growing e-GaSe single crystal, volatile component and curving solidification interface spoil the qualities of crystals. The GaSe single crystal in φ19 mm×65 mm size was grown by modified vertical Bridgman method. The crystallinity and optical properties of as-grown crystals were measured by XRD and transmission spectra, respectively. The FT-IR meas- urements indicated wide transparency over the spectral range (0.65-16 μm) and low absorption coefficient (

Published
2014

44. Pressure-Assisted Method for the Preparations of High-Quality AaGaS2and AgGaGeS4Crystals for Mid-Infrared Laser Applications

Author

Huang, Changbao, Mao, Mingsheng, Wu, Haixin, and Ma, Jiaren

Abstract

Recently developed chalcogenides nonlinear optical crystals have potential application in mid- to far-infrared laser fields. However, high-quality single crystals are hard to be prepared because of high vapor pressure of sulfur component and decomposition of chalcogenides during the polycrystalline synthesis and single-crystal growth. A pressure-assisted technique was performed to prepare stoichiometric AgGaS2and AgGaGeS4polycrystalline materials. On the basis of the synthesized polycrystalline materials, high-quality AgGaS2and AgGaGeS4single crystals were successfully obtained using the seed directional Bridgman method with a well-designed crucible-capsule technique. These single crystals possess high homogeneity and low absorption coefficient, making it can be applied in nonlinear optical experiments. The pressure-assisted method can also be suitable to prepare other chalcogenide and phosphide compounds. The method of polycrystalline synthesis and single crystals growth described in this work will be helpful for preparing other chalcogenides nonlinear optical crystals.

Published
2018
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46. First-principles study on linear and nonlinear optical properties of ZnGeP 2

Author

Wang Zhenyou, Wu Haixin, Ni Youbao, Cheng Xu-Dong, Huang Changbao, and Xiao Rui-Chun

Subjects
Physics, Nonlinear optical, Optics, Infrared, Phonon, business.industry, Mathematical analysis, Dispersion (optics), General Physics and Astronomy, Density functional theory, business
Abstract

The study of the linear and nonlinear optical properties of ZnGeP2 based on density functional theory has been carried out. In order to get a more physical picture in the infrared region, terms which are considered as the phonon effect were added to the calculated refractive dispersion curves. The phonon-corrected calculation curves show excellent agreement with experimental refractive indexes, which gives a better comprehension of the linear optical proprieties in the transparent region. The static nonlinear optical susceptibility was investigated using approaches based on the "sum over states" and the 2n + 1 theorem methods. Both of the results of these two methods reasonably coincided with the experimental results.

Published
2015

49. First principles study on the electronic structures and optical properties of Na2Ge2Se5

Author

Ni Youbao, Tang Xiao-Lu, Wang Zhenyou, Xiao Rui-Chun, Cheng Xu-Dong, Wu Haixin, and Huang Changbao

Subjects
Materials science, Physics::Optics, General Physics and Astronomy
Abstract

The optimized crystal structure, electronic structure and optical properties of Na2Ge2Se5, an excellent nonlinear crystal, are investigated by using pseudo-potential plane-wave method based on the first principles. The band structure, density of states, bond population, dielectric function, reflection spectrum, absorption spectrum, and codex refractive index of optimized structure of Na2Ge2Se5 are calculated. The results indicate that Na2Ge2Se5 is indirect wide-band semiconductor. The electronic transitions are mainly composed of Ge-4s, Ge-4p, Se-4s and Se-4p. The optical properties are determined by the interaction between Ge and Se, while Na contributes little. The reflectance spectrum and absorption spectrum indicate that there is strong absorption to ultraviolet radiation and static refractive index is 2.133. Na2Ge2Se5 possesses moderate birefringence. The results indicate that Na2Ge2Se5 is a good candidate for the optical crystals in the infrared region.

Published
2014

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