1 南京信息工程大学江苏省大气环境与装备技术协同创新中心，江苏 南京 210044
2 南京信息工程大学电子与信息工程学院，江苏 南京 210044
随着水下无线通信的发展，关于海洋环境量子通信的研究也逐渐成为热点。其中，研究海洋气泡对光量子在水下传输的影响具有重要意义。为了研究海洋气泡对水下量子通信信道性能的影响，根据海洋气泡的粒径分布模型，研究了气泡的散射特性，并根据气泡的消光系数，分析了不同条件参数对链路衰减、纠缠度、信道容量以及信道误码率的影响，并进行了仿真实验。结果表明：气泡浓度和传输距离的增大，使链路衰减和误码率增加，对于幅值阻尼信道、退极化信道和比特翻转信道，其信道容量均有所减小；随着气泡半径的增大、深度的减小，信道纠缠度降低。由此可见，海洋气泡对量子通信性能的影响不可忽略，在实际应用中为了保障水下量子通信的传输效率，应适当调节水下量子通信相关参数，减小海洋气泡环境对通信系统的影响。
海洋气泡 水下量子通信 链路衰减 信道纠缠度 信道容量 光学学报
2023, 43(18): 1806001
Author Affiliations
Abstract
1 School of Electronic and Information Engineering, Wuxi University, Wuxi 214105, China
2 Institute of Advanced Technology on Semiconductor Optics & Electronics, Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China
In this work, the surface morphology and internal defect evolution process of GaAs substrates implanted with light ions of different fluence combinations are studied. The influence of H and He ions implantation on the atomic mechanism of the blister phenomenon observed after annealing is investigated. Raman spectroscopy is used to measure the surface stress change of different samples before and after implantation and annealing. Optical microscopy and atomic force microscopy are used to characterize the morphology changes of the GaAs surface under different annealing conditions. The evolution of bubbles and defects in GaAs crystals is revealed by transmission electron microscopy. Through this study, it is hoped that ion implantation fluence, surface exfoliation efficiency and exfoliation cost can be optimized. At the same time, it also lays a foundation for the heterointegration of GaAs film on Si.
surface morphology internal defect evolution surface stress bubbles and defects Journal of Semiconductors
2023, 44(5): 052102
水下爆炸气泡载荷是造成舰船结构整体损伤的主要原因, 研究水下爆炸气泡动态特性对水中兵器研发和舰船防护等方面至关重要。从水下爆炸气泡脉动的载荷特性出发, 综述了气泡动力学理论、实验和数值模拟三方面的研究进展, 总结气泡非球状坍缩运动过程、气泡与不同结构表面耦合作用以及自由场中多气泡耦合作用等问题的典型研究成果。在现有研究成果的基础上, 提出应建立综合考虑气泡内部因素和水中不同环境因素的气泡运动力学模型; 针对非理想炸药水中爆炸气泡运动特性规律开展更系统的实验研究; 进一步加强近边界条件下多气泡耦合过程的研究工作等建议。
爆炸力学 水下爆炸 气泡 脉动 动态特性 explosive mechanics underwater explosion bubbles pulsation dynamic characteristics
Author Affiliations
Abstract
1 School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
2 Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, People’s Republic of China
3 School of Industrial Engineering, Purdue University, West Lafayette, IN 47906, United States of America
Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debris, and turbulent liquid flow generally deteriorate laser beam transmission stability, leading to low energy efficiency and poor surface quality. Here, we report that a continuous and directional high-speed microjet will form in the laser ablation zone if laser-induced primary cavitation bubbles asymmetrically collapse sequentially near the air-liquid interface under a critical thin liquid layer. The laser-induced microjet can instantaneously and directionally remove secondary bubbles and ablation debris around the laser ablation region, and thus a very stable material removal process can be obtained. The shadowgraphs of high-speed camera reveal that the average speed of laser-induced continuous microjet can be as high as 1.1 m s-1 in its initial 500 μm displacement. The coupling effect of laser ablation, mechanical impact along with the collapse of cavitation bubbles and flushing of high-speed microjet helps achieve a high material removal rate and significantly improved surface quality. We name this uncovered liquid-assisted laser ablation process as laser-induced microjet-assisted ablation (LIMJAA) based on its unique characteristics. High-quality microgrooves with a large depth-to-width ratio of 5.2 are obtained by LIMJAA with a single-pass laser scanning process in our experiments. LIMJAA is capable of machining various types of difficult-to-process materials with high-quality arrays of micro-channels, square and circle microscale through-holes. The results and disclosed mechanisms in our work provide a deep understanding of the role of laser-induced microjet in improving the processing quality of liquid-assisted laser micromachining.
liquid-assisted laser ablation laser-induced microjet cavitation bubbles laser microfabrication International Journal of Extreme Manufacturing
2022, 4(3): 035101
1 中建材玻璃新材料研究院集团有限公司，浮法玻璃新技术国家重点实验室，蚌埠 233010
2 硅基材料安徽省实验室，蚌埠 233010
中性医药玻璃具有优异的化学稳定性和热稳定性，被广泛应用于药物、食品等包装领域。本文研究了氧化物澄清剂CeO2，卤化物澄清剂NaCl和复合澄清剂NaClCeO2、NaClCeO2NaNO3对中性医药玻璃澄清效果的影响，定量分析了气泡熔占比、气泡个数、气泡平均直径的变化规律，探究出适用于中性医药玻璃的澄清剂。研究结果表明，中性医药玻璃液中加入NaClCeO2NaNO3后，气泡熔占比较低，气泡个数较少，气泡平均直径较大，添加NaClCeO2NaNO3时澄清效果要优于NaCl和CeO2。当加入0.4%（质量分数）NaCl0.20%（质量分数）CeO20.005 0%（质量分数）NaNO3时，在升温至1 550 ℃后3 h内，中性医药玻璃液的气泡熔占比降至0.6%，气泡个数减少到3个，气泡平均直径为0.60 mm，澄清效果较佳。
中性医药玻璃 澄清剂 气泡熔占比 气泡个数 气泡平均直径 neutral pharmaceutical glass refining agent area fraction number of bubbles mean bubble size
红外与激光工程
2022, 51(6): 20220274
Author Affiliations
Abstract
1 Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
2 State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
3 Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, China
4 Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
5 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
Owing to weak light-matter interactions in natural materials, it is difficult to dynamically tune and switch emission polarization states of plasmonic emitters (or antennas) at nanometer scales. Here, by using a control laser beam to induce a bubble (n=1.0) in water (n=1.333) to obtain a large index variation as high as |Δn|=0.333, the emission polarization of an ultra-small plasmonic emitter (~0.4λ2) is experimentally switched at nanometer scales. The plasmonic emitter consists of two orthogonal subwavelength metallic nanogroove antennas on a metal surface, and the separation of the two antennas is only sx=120 nm. The emission polarization state of the plasmonic emitter is related to the phase difference between the emission light from the two antennas. Because of a large refractive index variation (|Δn|=0.333), the phase difference is greatly changed when a microbubble emerges in water under a low-intensity control laser. As a result, the emission polarization of the ultra-small plasmonic emitter is dynamically switched from an elliptical polarization state to a linear polarization state, and the change of the degree of linear polarization is as high as Δγ≈0.66. Owing to weak light-matter interactions in natural materials, it is difficult to dynamically tune and switch emission polarization states of plasmonic emitters (or antennas) at nanometer scales. Here, by using a control laser beam to induce a bubble (n=1.0) in water (n=1.333) to obtain a large index variation as high as |Δn|=0.333, the emission polarization of an ultra-small plasmonic emitter (~0.4λ2) is experimentally switched at nanometer scales. The plasmonic emitter consists of two orthogonal subwavelength metallic nanogroove antennas on a metal surface, and the separation of the two antennas is only sx=120 nm. The emission polarization state of the plasmonic emitter is related to the phase difference between the emission light from the two antennas. Because of a large refractive index variation (|Δn|=0.333), the phase difference is greatly changed when a microbubble emerges in water under a low-intensity control laser. As a result, the emission polarization of the ultra-small plasmonic emitter is dynamically switched from an elliptical polarization state to a linear polarization state, and the change of the degree of linear polarization is as high as Δγ≈0.66.
plasmonic emitters nanometer scales polarization manipulation dynamical switching bubbles Opto-Electronic Advances
2022, 5(8): 200100
强激光与粒子束
2022, 34(8): 082203
山东理工大学 机械工程学院，山东 淄博 255000
为了减小激光切割硅晶圆时的热效应，选择去离子水作为辅助液体进行激光切割实验，研究了水下切割时激光烧蚀激发气泡对硅片表面造成的不良影响。为解决水下激光切割进程中诱导气泡大面积粘结在硅片表面的问题，提出了去离子水混入乙醇溶液的实验方案，分析了水下激光切割中激光参数和乙醇浓度对切割质量的影响。实验结果表明，采用乙醇溶液作为辅助介质能明显减少粘结气泡的数量，减轻气泡破溃冲击带来的负面影响。实验采用乙醇浓度5 wt.%时切割得到的硅片比纯水中切割得到的硅表面影响区减小50%以上、切缝宽减幅约20%，有效提升了激光切割质量。
激光切割 硅 乙醇 气泡 表面质量 laser dicing silicon ethanol bubbles surface quality 红外与激光工程
2022, 51(4): 20210333
1 西安理工大学自动化与信息工程学院, 陕西 西安 710048
2 澳门科技大学资讯科技学院, 澳门 999078
为研究气-海跨介质的蓝绿激光传输特性,针对气-海跨介质界面及海面下气泡层,依据基尔霍夫近似、Mie理论与Beer理论建立了蓝绿激光通过海面-气泡层的下行传输模型。充分考虑了受风速影响的海面高度起伏、海水中气泡浓度变化、海水中洁净气泡和有薄膜覆盖气泡的混合等因素,数值计算了蓝绿激光经过海面-气泡层的透过率随风速、海水中的传输深度以及接收平面与发射平面夹角的变化关系。结果表明,蓝绿激光通过气-海界面及海水中的透过率主要取决于风速的大小与激光在海水中的传输深度;随着风速的增大,海面粗糙度与上层海洋中气泡浓度增大,激光透过率降低;与海水相比,气泡层对激光透过率的影响会随着深度的增加而降低;对于半径大于10 μm的气泡,蛋白质薄膜的覆盖对蓝绿激光的衰减影响不大。
激光光学 蓝绿激光 粗糙海面 海中气泡 Mie理论 透过率
