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21. Metasurface integrated Vertical Cavity Surface Emitting Lasers for programmable directional lasing emissions

Author

Xie, Yi-Yang, Ni, Pei-Nan, Wang, Qiu-Hua, Kan, Qiang, Briere, Gauthier, Chen, Pei-Pei, Zhao, Zhuang-Zhuang, Delga, Alexandre, Ren, Hao-Ran, Chen, Hong-Da, Xu, Chen, and Genevet, Patrice

Subjects
Physics - Optics
Abstract

Vertical cavity surface emitting lasers (VCSELs) have made indispensable contributions to the development of modern optoelectronic technologies. However, arbitrary beam shaping of VCSELs within a compact system still remains inaccessible till now. The emerging ultra-thin flat optical structures, namely metasurfaces, offer a powerful technique to manipulate electromagnetic fields with subwavelength spatial resolution. Here, we show that the monolithic integration of dielectric metasurfaces with VCSELs enables remarkable arbitrary control of the laser beam profiles, including self-collimation, Bessel and Vortex lasers, with high efficiency. Such wafer-level integration of metasurface through VCSELs-compatible technology simplifies the assembling process and preserves the high performance of the VCSELs. We envision that our approach can be implemented in various wide-field applications, such as optical fibre communications, laser printing, smartphones, optical sensing, face recognition, directional displays and ultra-compact light detection and ranging (LiDAR).

Published
2019
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39. Research progress on the fluid metallogenic mechanism of granitic pegmatite-type rare metal deposits

Author

ZHENG Fanbo, WANG Guoguang, and NI Pei

Subjects
granitic pegmatite-type deposit, rare element, ore-forming fluids, metallogenic mechanism, Geology, QE1-996.5
Abstract

Strategic rare metals have irreplaceable important use to emerging industry development. Granitic pegmatite is the main source of rare metals, and their fluid characteristics and metallogenic mechanism are hot topics. This paper mainly focuses on fluid properties and metallogenic mechanism of granitic pegmatite-type rare metal deposits. Ore-forming fluids of the granitic pegmatite-type rare metal deposits are generally enriched in volatile (B, P, F and H2O) and ore-forming elements, with low viscosity, low nucleation rate, but strong element solubility and mobility. The ore-forming fluids of the granitic pegmatite-type rare metal deposit were argued to be captured under the condition of high temperature and high pressure, or the temperature of as low as 350℃ under the condition of supercooling. The high crystallization differentiation evolution of granitic magma and the small proportion of crustal material rich in ore-forming elements are the two main mechanisms for the formation of ore-forming granitic pegmatite. Fluid immiscibility and constitutional zone refining are important means for further enrichment of rare metals in the process of magmatic hydrothermal evolution. The largest Jiajika granitic pegmatite-type lithium deposit in China is an ideal laboratory to study this kind of deposit.

Published
2021
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42. Effect of BaO on viscosity and structure of B2O3–SiO2–Al2O3–Na2O–BaO glass lubricant.

Author

Cui, Lei, Ni, Pei‐yuan, Lv, Wei, and Li, Ying

Subjects
*MOLTEN glass, *PHOTOELECTRON spectroscopy, *MOLECULAR dynamics, *EXTRUSION process, *RAMAN spectroscopy
Abstract

Glass lubricant with a suitable viscosity is critical for the efficient production of high‐quality titanium alloy in hot extrusion process. In this study, a new glass lubricant, (30.93‐0.309x)B2O3‐(48.45‐0.485x)SiO2‐(7.22‐0.072x)Al2O3‐(13.4‐0.134x)Na2O‐xBaO (BSANB), was proposed for titanium alloy hot extrusion. The effect of BaO content varying from 0 wt.% to 15 wt.% on its viscosity was investigated, and the mechanism of viscosity change was clarified through melt structure analysis by using molecular dynamics (MD) simulation, X‐ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The glass viscosity was measured in the temperature range of 950°C to 1100°C, and the atomic self‐diffusion coefficient of the glass melt was calculated. The results demonstrated that the BaO content has a significant influence on the viscosity of the BSANB glass at the hot extrusion temperature range. The viscosity value at 950°C was decreased by 52.87%, from 103.5 Pa·s to 48.8 Pa·s, when BaO content was increased from 0 wt.% to 15 wt.%. MD simulation results of the BSANB glass show that the self‐diffusion coefficient of Si atoms was lower than that of Al and B atoms, indicating that Si‐O bonds were more stable in the melt. The diffusion coefficient of Si atom was directly related to the rheological behavior of the melt, which can be reflected by the melt viscosity. The results of MD simulation, XPS and Raman spectral fitting at 950°C showed an increase in the amounts of Q1, Q0 and [BO4], while the amounts of Q2, Q3, Q4 and [AlO4] were decreased when BaO content was increased from 0 wt.% to 15 wt.%. This demonstrated that the melt network was depolymerized with an increased BaO content, which determined the melt viscosity change. In addition, the mechanism responsible for glass viscosity reduction due to temperature increase was also discussed. [ABSTRACT FROM AUTHOR]

Published
2025
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44. Effect of B2O3/SiO2 molar ratio and B2O3 content on viscosity and structure of B2O3–SiO2–Al2O3–Na2O–TiO2 glass lubricant

Author

Cui, Lei, Lv, Wei, Ni, Pei‐yuan, Wang, Huailiu, and Li, Ying

Subjects
HOT working of metals, VISCOSITY, GLASS structure, EXTRUSION process, DEGREE of polymerization, TITANIUM powder, LUBRICATION & lubricants
Abstract

Glass lubricant with a suitable viscosity is essential for producing high‐quality titanium products by the hot extrusion process. In this study, a novel lubricant of B2O3–SiO2–Al2O3–Na2O–TiO2 (BSANT) glass was proposed, where the effects of B2O3/SiO2 molar ratio (B/Si) and B2O3 content on viscosity and structure were investigated. The results showed that the BSANT glass viscosity was gradually decreased, and the viscous activation energy was decreased by 20.24% with an increased B/Si ratio from 0.415 to 0.719. This was attributed to the decreased amounts of Q3, [BO4], [AlO4], and bridging oxygen (BO) in the network structure, which in turn resulted in a decreased network degree of polymerization. When B2O3 content was increased from 18.70 to 33.12 mol.%, the melt viscosity value at 950 ℃ was decreased by 64.51%, and the viscous activation energy was reduced by 15.82%. Boron anomalies were also observed in glass melts with the B2O3 content from 28.28 to 33.12 mol.%. The mechanisms responsible for this phenomenon were thoroughly discussed in the study. Additionally, a comparison and discussion of the applications of glass lubricants in metal hot working were presented. A glass lubricant with a specific composition was recommended for use in hot extrusion process within the temperature range of 950–1100°C due to its relatively stable viscosity properties. A novel lubricant of B2O3–SiO2–Al2O3–Na2O–TiO2 (BSANT) glass was proposed, where the effects of B2O3/SiO2 molar ratio (B/Si) and B2O3 content on viscosity and structure were investigated. A glass lubricant with a specific composition was recommended for use in hot extrusion process within the temperature range of 950–1100°C due to its relatively stable viscosity properties. [ABSTRACT FROM AUTHOR]

Published
2024
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