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A new laser blow-off system for use in impurity transport studies on Alcator C-Mod was developed and installed for the 2009 run campaign. Its design included capabilities for multiple impurity injections during a single plasma pulse and remote manipulation of the ablated spot size. The system uses a 0.68 J, Nd:YAG laser operating at up to 10 Hz coupled with the fast beam steering via a 2D piezoelectric mirror mount able to move spot locations in the 100 ms between laser pulses and a remote controllable optical train that allow ablated spot sizes to vary from ~0.5 to 7 mm. The ability to ablate a wide range in target Z along with Alcator C-Mod's extensive diagnostic capabilities (soft x-ray, vacuum ultraviolet (VUV), charge exchange spectroscopy, etc.) allows for detailed studies of the impurity transport dependencies and mechanisms. This system has demonstrated the achievement of all its design goals including the ability for non-perturbative operation allowing for insight into underlying impurity transport processes. A detailed overview of the laser blow-off system and initial results of operation are presented. This includes an investigation into the characterization of impurity confinement in the I-mode confinement regime recently investigated on C-Mod. 相似文献
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A. G. Poleshchuk A. A. Kutanov V. P. Bessmeltsev V. P. Korolkov R. V. Shimanskii A. I. Malyshev A. E. Matochkin N. V. Goloshevskii K. V. Makarov V. P. Makarov I. A. Snimshchikov N. Sydyk uulu 《Optoelectronics, Instrumentation and Data Processing》2010,46(2):171-180
Results of development and testing of a scanning system of interference lithography are presented. The system is designed to form diffractive microstructures consisting of microgratings with a specified orientation, a size of 5–10 µm, and a period ranging from 0.6 to 1.5 µm. The total writing field of the system is 300 × 300 mm. The system is used to study direct laser writing of microgratings on chromium and amorphous silicon films applied by the method of magnetron sputtering onto the glass substrate surfaces. The device and technology of direct writing of microgratings can be further used to form antireflective subwave coatings of optical elements and graphical microstructured identification marks for product protection and also to manufacture diffractive attenuators of laser radiation. 相似文献
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Yang Chao-jun Zhang Yong-kang Zhou Jian-zhong Ni Ming-xiong Du Jian-jun Huang Shu Feng Ai-xin Zhang Lei-hong 《Frontiers of Mechanical Engineering in China》2006,1(4):448-451
The mechanism of laser shock deformation and the reason for the production of the shockwave are introduced. An evaluation
formula of the detonation wave pressure in the system of laser, energy transferring-medium and sheet metal is built according
to the theory of detonation wave and blasting gas-dynamics. The minimal energy of the laser pulse is evaluated on the basis
of the formula of the laser shock pressure and evaluation of dynamic yielding strength. The experiment is also validated.
The result shows that the quantity of sheet metal deforming is nonlinearly increased with laser energy, i.e., pressure of
the laser shock wave. Under a laser-induced ultra-high pressure and high strain rate, structural steels and composite materials
undergo plastic deformation.
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Translated from Journal of Nanjing University of Aeronautics and Astronautic, 2005(S1) (in Chinese) 相似文献
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K. Myller M. Juuti K.-E. Peiponen R. Silvennoinen E. Heikkinen 《Precision Engineering》2006,30(4):443-447
Planar, convex and concave metal surfaces were produced by utilizing finishing processes that are exploited in the production of tools for plastics injection molding. A novel glossmeter, the so-called diffractive optical element-based glossmeter (DOG), was used for the inspection of the gloss of the surfaces. The Society of the Plastics Industry (SPI) A1 standard, which has the lowest surface roughness of such standards, served as a reference for the success of the finishing process. The results show that by using DOG we can gain local microscopic and macroscopic information on the gloss and its variation. The DOG is sufficiently sensitive to detect small gloss variation as well as the texture of the surface, e.g. anisotropy in surface marks. Some of the surfaces in this study have a higher surface quality than the A1 surface. 相似文献
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Micromanipulation by laser microbeam and optical tweezers: from plant cells to single molecules 总被引:2,自引:0,他引:2
K. O. Greulich G. Pilarczyk A. Hoffmann G. Meyer Zu Hörste B. Schäfer V. Uhl S. Monajembashi 《Journal of microscopy》2000,198(3):182-187
Complete manipulation by laser light allows precise and gentle treatment of plant cells, subcellular structures, and even individual DNA molecules. Recently, affordable lasers have become available for the construction of microbeams as well as for optical tweezers. This may generate new interest in these tools for plant biologists. Early experiments, reviewed in this journal, showed that laser supported microinjection of material into plant cells or tissues circumvents mechanical problems encountered in microinjection by fragile glass capillaries. Plant protoplasts could be fused with each other when under microscopical observation, and it was no major problem to generate a triple or quadruple fusion product. In the present paper we review experiments where membrane material was prepared from root hair tips and microgravity was simulated in algae. As many plant cells are transparent, it is possible to work inside living, intact cells. New experiments show that it is possible to release by optical micromanipulation, with high spatial resolutions, intracellular calcium from caged compounds and to study calcium oscillations. An example for avian cardiac tissue is given, but the technique is also suitable for plant cell research. As a more technical tool, optical tweezers can be used to spatially fix subcellular structures otherwise moving inside a cell and thus make them available for investigation with a confocal microscope even when the time for image formation is extended (for example at low fluorescence emission). A molecular biological example is the handling of chromosomes and isolated individual DNA molecules by laser microtools. For example, chromosomes can be cut along complex trajectories, not only perpendicular to their long axis. Single DNA molecules are cut by the laser microbeam and, after coupling such a molecule to a polystrene microbead, are handled in complex geometries. Here, the individual DNA molecules are made visible with a conventional fluorescence microscope by fluorescent dyes such as SYBRGreen. The cutting of a single DNA molecule by molecules of the restriction endonuclease EcoRI can be observed directly, i.e. a type of single molecule restriction analysis is possible. Finally, mechanical properties of individual DNA molecules can be observed directly. 相似文献
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对光学自由曲面设计的关键问题——光学自由曲面的表征模型进行了研究。在传统高斯径向基模型的基础上,通过改善基函数的分布特性以及基于面形斜率调整基函数的形状因子,建立了基于面形斜率的高斯径向基表征模型。利用建立的模型、传统径向基模型和Zernike多项式模型拟合了不同类型的自由曲面,并进行了分析比较。结果证实了文中提出的模型较传统径向基模型的面形拟合精度提高了1~2个数量级,具有较强的面形表征能力。应用该模型进行了离轴三反系统的设计,结果显示设计的三反系统的全视场平均调制传递函数(MTF)达到80%以上。与传统面形表征模型相比,该模型的应用提高了系统的像差平衡能力,改善了系统的成像质量。综合分析表明,该模型适用于表征具有显著非对称性的、面形矢高带有显著局域性变化的自由曲面,有望应用于具有大离轴量和大视场的光学系统设计中。 相似文献
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A method is described for measuring the profile of a quasi-conical mirror surface along one of its axial generators. A laser beam is made to scan the surface and the variation in reflected beam angle is measured by autocollimation. Integrating the angle with respect to distance along the generator gives the profile height to within ±5 nm. The method has application to the metrology of X-ray microscope reflecting objectives 相似文献
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光学玻璃的激光微结构化砂轮精密磨削 总被引:1,自引:0,他引:1
为了降低大磨粒金刚石砂轮磨削光学玻璃时的亚表层损伤,利用纳秒脉冲激光对金刚石砂轮进行了表面微结构化加工,并采用该砂轮研究了光学玻璃的精密磨削加工。首先,计算了金刚石磨粒在纳秒脉冲激光辐射下的烧蚀阈值和激光束腰半径;然后,分析了纳秒脉冲激光在金刚石磨粒上加工的微结构形貌以及微结构化过程中的热损伤;最后,采用微结构化大磨粒金刚石砂轮进行光学玻璃的磨削实验,并分析了亚表层的损伤情况。实验结果表明:金刚石磨粒在纳秒脉冲激光辐射下的烧蚀阈值为0.89J/cm,激光束腰半径为17.16μm。在粒度为150μm的大磨粒电镀金刚石砂轮上可以实现结构尺寸为20μm的微结构表面加工。与传统金刚石砂轮相比,微结构化砂轮磨削后的光学玻璃亚表层损伤深度降低了40%,达到了降低光学玻璃磨削亚表层损伤的目的。 相似文献
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介绍了为提高惯性约束聚变(ICF)激光驱动装置的光束质量和输出功率,我国在神光系列激光装置的建设、运行和性能提升方面开展的工作。综述了我国近年来ICF激光装置用光学元器件的重要研究进展。文中涉及了高纯金属铪和磷酸二氢钾(KDP)等原材料的制备和四大主材(钕玻璃、高纯度KDP、熔石英和KDP/高掺氘KDP(KDP/DKDP晶体)的熔炼、加工和生长。描述了元器件的冷加工(针对钕玻璃、白玻璃、KDP晶体)技术和镀膜技术(针对介质膜和化学膜)。最后,给出了针对大口径光学元件工序检及终检开展的多项关键检测技术。文中介绍的关键技术与工艺满足了绝大部分光学元器件的需求,显著提升了光学元器件的研发和生产能力。 相似文献
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E. V. Sysoev I. V. Golubev R. V. Kulikov 《Optoelectronics, Instrumentation and Data Processing》2007,43(5):476-480
A method for detecting surface defects is discussed. The method is based on analyzing the light scattering function with reference to the problem concerned with automatic control of a fuel cladding surface. 相似文献
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根据光学玻璃元件超精密加工技术的需求,研究自旋转式和行星旋转式磁性复合流体(MCF)抛光的应力分布和材料去除率。首先,设计可实现自旋转和行星旋转抛光装置,搭建抛光实验平台;然后,进行自旋转式和行星旋转式MCF抛光实验,通过自行设计抛光应力分布测试实验分析了两种抛光方式的应力分布规律;最后,通过定点抛光实验,对抛光前后的工件表面轮廓进行检测,计算并分析两种抛光方式的材料去除率。实验结果表明,立式的两种抛光方式,正应力均明显大于剪切应力,工件外侧受到的剪切应力大于中心受到的剪切应力,行星式抛光的材料去除率明显大于自旋转式抛光的材料去除率。 相似文献
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Porous copper surfaces show their great merits in the applications of chemical reaction, sound absorption and heat transfer. In this study, a laser micromilling method is proposed to fabricate porous surfaces with homogeneous micro-holes and cavities of the size about 1–15 μm on pure copper plates in a one-step process. The laser micromilling was performed by a pulsed fiber laser via the multiple–pass reciprocating scanning strategy. Based on the measurement of scanning electron microscope (SEM) and 3D laser scanning confocal microscope, the formation of surface structures was investigated together with the laser ablation mechanisms. The effects of laser processing parameters, i.e., laser fluence, scanning speed, number of scanning cycles and scanning interval, on the formation and surface morphology of porous surfaces were systematically assessed. Furthermore, the wettability of the porous copper surfaces was also evaluated by measuring the static contact angle of water. The results showed that the laser fluence played the most significant role on the formation of porous copper surfaces. The average depth and surface roughness of porous copper surfaces increased with increasing the laser fluence and number of scanning cycles while decreased with the increase in scanning interval. The scanning speed played little influence on the formation of porous copper surfaces. These results can be closely related to the variation of energy density and re-melting process during the laser micromilling process. Moreover, all the copper porous surfaces were found to be hydrophobic. The contact angle of porous copper surfaces was significantly dependent on laser fluence, but weakly affected by the scanning speed and number of scanning cycles. 相似文献
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将一种新颖的基于腐蚀型多模光纤MMF级联的干涉型光纤传感器和光纤光栅传感器相结合,提出一种新的可以同时测量温度和液位的光纤传感器装置,并对其实验结果进行分析,光纤光栅和激光干涉仪作为激光光腔的滤波器,对应这两个滤波器,输出两个稳定波长,这两个波长对液位和温度有不同的反映特征。通过FBG输出的波长对液位不敏感,对温度的敏感性是0.012 3nm/℃。通过干涉仪输出的波长对液位敏感,并且灵敏度是0.229 4 nm/mm,它的温度敏感性是0.064 8 nm/℃。这样,根据不同的液位和温度的光谱响应,可以实现同时测量,该传感器与其他光纤传感器相比有不受检测范围限制,高分辨率和高灵敏度的优势。 相似文献
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