熔石英光学元件加工亚表面缺陷检测及抑制技术研究进展

熔石英材料因具有硬度大、热膨胀系数低、透射光谱范围广等良好的机械性能和热学、光学特性,广泛应用于国防、航天等领域中关键光学元件的制造。作为一种典型的硬脆材料,在传统的研磨抛光加工中,不可避免地会引入亚表面层的微裂纹、划痕等结构性缺陷,这些缺陷会严重降低熔石英元件在高功率激光使用环境下的激光损伤阈值,并影响其在高冲击载荷使用环境下的抗断裂损伤能力。从硬脆材料的磨削机理出发,对熔石英光学元件亚表面缺陷的产生机制、亚表面缺陷的检测技术、熔石英亚表面缺陷抑制技术的研究现状进行综述,重点对比针对加工亚表面缺陷的有损检测和无损检测技术的优缺点,探讨多种先进表面加工技术在抑制熔石英光学元件亚表面缺陷中的应用。希望为优化大口径、高精度、高质量熔石英光学元件加工工艺,并提升其在高功率激光、高冲击载荷等极端服役环境下使用性能、延缓其使用寿命提供有益参考。     

先进光学制造执行系统研究与开发

先进光学制造技术是为适应现代高科技发展的需要而发展起来的超精密加工技术,针对大口径、高精度光学元件制造过程中定量化水平低、成品率不高、重复性和一致性较差等问题,应用业务驱动和RUP方法,分析、研究了先进光学制造工艺流程、制造执行系统需求、体系架构和关键技术,提出了以大口径、高精密元件为核心,工艺流程驱动的先进光学制造执行系统,应用效果表明,实现了精密光学元件制造工艺的动态编制、制造信息的集成,提高了先进光学制造的信息化程度和效率.     

锂离子电池负极用一维ZnMn2O4纳米束材料的制备及电化学性能

以乙酸锌、乙酸锰和碳酸氢铵为原料，以酒石酸钾钠为结构导向剂，通过200℃溶剂热反应制备纳米束前驱体，根据前驱体形貌确定较优的酒石酸钾钠添加量和溶剂热反应时间；将前驱体分别在250,350℃高温焙烧2 h制备锂离子电池负极用ZnMn₂O₄纳米束，研究了ZnMn₂O₄纳米束的组织结构及电化学性能。结果表明：当外加酒石酸钾钠为1 mmol,溶剂热反应时间为12 h时，可得到结构完整的一维纳米束；2种焙烧温度均可以得到结构完整的ZnMn₂O₄纳米束，但350℃焙烧得到的ZnMn₂O₄纳米束表现出更优异的电化学性能，在100 mA·g^-1的电流密度下循环60次后，其比容量仍可维持在892 mA·h·g^-1,在2 A·g^-1的大电流密度下，其比容量依然能够达到416.2 mA·h·g^-1。     

军用技术转民用推广目录(续)

正17高损伤阈值激光薄膜元件制造及产业化【技术开发单位】中国科学院上海光学精密机械研究所通过建立和优化光学元件机械加工、清洗、镀膜、检测技术,形成完善的高损伤阈值激光薄膜元件制备技术方案及生产流程线,从而完成高损伤阈值、优良光性质量和波面质量的激光薄膜元件制造产业     

高抗激光损伤阈值光栅后处理抛光技术研究

脉冲压缩光栅是实现高能量激光的核心光学元器件,其制造过程中产生的表面污染物和微结构缺陷成为限制高功率激光系统发展的技术瓶颈,为了提升光栅的激光诱导损伤阈值,提出利用磁性复合流体进行脉冲压缩光栅(PCG)后处理抛光研究。对抛光前后光栅样品的微观结构,表面形貌、表面粗糙度、衍射效率和激光诱导损伤阈值等参数进行测量,进行抛光前后光栅表面质量和光栅性能的评估。研究发现,磁性复合流体抛光能够在不破坏实际光栅结构的前提下抑制加工过程产生的毛刺,微结构缺陷等;经3 min抛光后,光栅顶部表面粗糙度从21.36 nm下降到3.73 nm;激光诱导损伤阈值从2.8 J/cm²提高到3.8 J/cm²,抗激光损伤性能提升35.7%,且不影响衍射效率。实验结果表明：磁性复合流体抛光是一种可以提高光栅元件表面质量,提升光栅元件光学性能的有效方法。     

光学元件表面缺陷检测方法研究现状

随着科学技术的发展,人们对光学元件的表面粗糙度和表面面形精度提出了越来越高的要求,光学元件表面缺陷检测技术也受到了广泛重视。通过简述表面缺陷的类型,强调了缺陷给光学系统带来的危害,由此分析和讨论了目前国内外对光学元件疵病的检测方法,并指出各种方法的优缺点,同时对机器视觉技术在疵病检测方面的应用进行了介绍,还探讨了光学元件表面缺陷检测技术未来发展需要注意解决的问题。     

光学元件表面疵病检测仪的精度建模及预测

为了对疵病检测仪的精度进行预测并对设计方案的合理性进行验证,基于多体系统理论对疵病检测仪机械运动机构进行了精度建模。用低序体阵列和拓扑结构描述了疵病检测仪的结构特点,提出了疵病检测仪的精度模型,针对光学系统的要求进行了误差分离。基于该精度模型,以典型光学元件为例提出了误差补偿的计算流程,对疵病检测仪的精度进行预测。预测结果表明,光学探头的成像点与待测点沿光学探头光轴方向误差最大值为3.0μm,满足光学探头景深20μm的检测要求,同时光学探头成像点与光学元件待测点垂直于光轴方向误差及光学探头光轴与光学元件待测点处表面法向的夹角均在设计指标内。     

先进光学数字化制造装备和工艺与信息融合技术研究

通过先进光学数字化制造装备、工艺与信息融合技术,能有效整合、打通光学元件制造过程中的数字化加工和检测装备,消除数字化装备孤岛;达到光学元件制造生产线上下游装备、工艺与信息的共享和协同,提升大口径超精密光学元件制造效率。应用流程分析和快速原型化方法,以光学元件数字化制造工艺流程线为基础,分析研究了数字化先进光学制造装备、工艺和信息融合技术,初步构建了数字化光学制造装备、工艺和信息融合原型系统。     

荧光成像技术无损探测光学元件亚表面缺陷

为了建立有效无损的亚表面缺陷探测技术,本文开展了光学元件亚表面缺陷的荧光成像技术研究,通过系统优化激发波长、成像光谱、成像光路及探测器等影响探测精度和探测灵敏度的参数,研制出小口径荧光缺陷检测样机。基于该样机对一系列精抛光熔石英和飞切KDP晶体元件的散射缺陷和荧光缺陷进行了表征,获得了各类样品亚表面缺陷所占的比重差异很大,从0.012%到1.1%不等。利用统计学方法分析了亚表面缺陷与损伤阈值的关系,结果显示,熔石英亚表面缺陷与损伤阈值相关曲线的R~2值为0.907,KDP晶体亚表面缺陷与损伤阈值相关曲线的R~2值为0.947,均属于强相关。该研究结果可评价光学元件的加工质量,用于指导紫外光学元件加工工艺,并且由于该探测技术具有无损、快速的特点,因此可应用于大口径紫外光学元件全口径亚表面缺陷探测,具有极其重要的工程意义。     

晶体材料纳米切削加工机理的研究

正纳米加工技术已成为国家科学技术发展水平的重要标志,国防战略发展和纳米级高精度、高质量、低损伤尖端产品的迫切需求,促进了纳米加工技术的快速发展。在纳米尺度,理解材料的变形、去除机理对于加工高质量的微纳器件至关重要,多晶材料作为制造微纳器件的主体,具有晶粒尺寸较小、大比例晶界和缺陷结构极少的特征,但目前对于多晶材料的去除机理仍缺乏研究基础和理论依据。纳米加工实验由于研究对象尺寸达到纳米量级,存在加工过程中材料的组织结构变化及缺陷演化难以动态观测和控制,可重复性差等问题,使之难以获得满意结果。从而科学计算和计算机仿真技术成为研究纳米加工     

Study on advanced nanoscale near-field photolithography

At present, applying a near-field optical microscope to photolithographic line segment fabrication can only obtain nanoscale line segments of equal cutting depths, and cannot result in 3D shape fabrication. This study proposes an innovative line segment fabrication model of near-field photolithography that adjusts an optical fiber probe's field distance to control the exposure energy density, and moreover constructs an exposure energy density analysis method of the innovative photolithographic line segment fabrication. During the exposure simulation process of the innovative line segment fabrication model of near-field photolithography, the near-field distance between the optical fiber probe and the photoresist surface increases gradually, whereas the exposure energy density distribution decreases gradually. As a result, the cutting depth becomes shallower and the full-width at half maximum (FWHM) increases. The results of this study can serve as a theoretical reference for developing advanced nanoscale near-field photolithography techniques, to which an important and groundbreaking contribution is made.     

Photoplastic near-field optical probe with sub-100 nm aperture made by replication from a nanomould

Polymers have the ability to conform to surface contours down to a few nanometres. We studied the filling of transparent epoxy‐type EPON SU‐8 into nanoscale apertures made in a thin metal film as a new method for polymer/metal near‐field optical structures. Mould replica processes combining silicon micromachining with the photo‐curable SU‐8 offer great potential for low‐cost nanostructure fabrication. In addition to offering a route for mass production, the transparent pyramidal probes are expected to improve light transmission thanks to a wider geometry near the aperture. By combining silicon MEMS, mould geometry tuning by oxidation, anti‐adhesion coating by self‐assembled monolayer and mechanical release steps, we propose an advanced method for near‐field optical probe fabrication. The major improvement is the possibility to fabricate nanoscale apertures directly on wafer scale during the microfabrication process and not on free‐standing tips. Optical measurements were performed with the fabricated probes. The full width half maximum after a Gaussian fit of the intensity profile indicates a lateral optical resolution of ≈ 60 nm.     

Rapid fabrication of large aspheric optics

By combining efficient fabrication processes and advanced testing methods, a real production capability exists for the manufacture of large, aspheric optics. Currently, a five-axis computer-controlled optical surfacing unit is used for rapid grinding and polishing of elements up to four metres in size. This paper decribed the processes and equipment in use today and concludes with a scenario for meeting projected future fabrication needs.     

无基膜高深宽比双面集成微结构元件的制作

基于双面集成微结构薄片元件在集成光学成像、光束整形等方面的应用日益普及,针对其中一些一体化、高深宽比结构在制作方面的难点问题,本文提出一种无基膜支撑、高深宽比的双面集成微结构元件的制作新方法——紫外压印改进技术。通过该方法,成功地制作了无基膜、高深宽比结构的集成导光板样品;样品上下表面微结构形貌与金属模具在误差范围内保持一致,转印复制过程的物理结构形变小,且样品的厚度整体均匀、平整无翘曲。实验结果表明,本文提出的紫外压印改进技术方法能有效地制作无基膜支撑、双面集成高深宽比的微结构元件,可望在集成光学成像及光束整形、匀光、导光、聚光等光学器件制作领域有良好应用。     

应用于冷光学组件的透镜支撑技术研究

对于采用冷光学技术的短波红外透射式成像系统,由于光学元件及支撑结构的加工、装调温度与实际工作温度差异较大,几何形状的变化差异将导致光学元件出现位置误差,甚至受到破坏。本文根据低温红外系统对光机结构的设计要求,遵循均一性和不调整两个原则设计和加工一套短波红外成像系统的光机结构。在透镜和支撑结构件的配合面上分别加工45°的斜面,以充分适应光学元件与其支撑结构在温度变化过程的热胀冷缩,避免了光学元件和支撑结构由于受热变形差异过大而产生的不可恢复性破坏,最后通过实验验证了该光学支撑方案在80K的低温下具有良好的成像效果,本文的研究为今后大温差下的红外光机系统设计提供了较高的参考价值。     

基于共焦成像法的亚表层损伤散射仿真

光学零件的亚表面缺陷直接影响其使用性能和抗激光损伤阈值等重要指标,而造成这些危害的根本原因是由损伤层引入的入射光的散射。采用时域有限差分(FDTD)法,结合共焦层析测量系统进行模拟仿真。首先,针对常见的光学材料,分析了入射光经由亚表层中的微裂纹、气泡等常见缺陷调制后的光场分布,并结合不同形态参数和光学参数建立模型;其次,引入球面波激励源,模拟计算了入射波聚焦点沿固定间隔逐渐偏离缺陷时的散射分布。结果表明:共焦层析测量系统能够实现对亚表层损伤的测量,满足纵向响应函数趋势。     

Assessment of damage detection methods in GRID-LOCK® structures

Bonded metallic GRID-LOCK^® structures are being adopted for a variety of aerospace applications due to their structural efficiency and damage tolerance. However, effective damage detection in these structures is complicated by a lack of interior access. In this paper, the feasibility of various non-destructive evaluation (NDE) techniques for detecting the presence, location, and magnitude of damage in GRID-LOCK^® is investigated. Experiments conducted on a GRID-LOCK^® test structure reveal that vibration-based damage detection and optical nde methods are superior to ultrasonic C-scans in detecting disbond defects. Finite-element analysis (FEA) is used to interpret experimental results and highlight the advantages of alternate NDE approaches.     

纳米制备与表征

Aretheregreatthingstobediscoveredatthenanoscale ?Theanswerisalmostcertainly“yes” .Fromthemicroscaletothenanoscale ,itisfarfromjustscalingdown ,itisa“greatleapforward”intoacompletenewregimewherethephysicalandchemicalpropertiesofmaterialsexhibitsizedependentbehaviour.Athoroughunderstandingofthenewphysicsandchemistryatthenanometerscalewillleadtothedesignandfabricationofsmartnewfunctionalmaterialsanddevices,forin stance ,electronicdevicesthatoperateonthebasicprinciplesofquantummechanics.Nanofa…     

光学元件的疵病检测及现状

介绍了光学元件的疵病类型以及疵病检测标准,全面介绍了光学元件疵病检测方法的国内外发展现状。归纳出目前光学元件的疵病检测标准和检测方法的发展趋势及关键技术。分析表明,目前已有的疵病检测方法中还缺乏一种检测手段可以做到对所有类型疵病实现所需精度的检测,并且由于视场受限、难以定量等技术障碍而无法建立高效、自动化的检测分析设备。     

Near-field optical patterning on chloromethylated polyimide

Near-field scanning optical microscopy (NSOM) coupled with laser is used in nano-scale processing to make nano-scale dots or nano-scale structure. Nano-sclae processing using NSOM coupled with laser can be applied to photo- chemical etching process on crstalline silicon, to additive processes on some polymers, to subtraction processes on SAMs and other polymers. And it can be used to change material’s optical properties in nano-scale geometry. As above, nano-scale processing using NSOM coupled with laser has an advantage that it can be applied to various processes. In this work, by using NSOM coupled with 266nm UV laser, nanoscale patterns were fabricated on chloromethylated polyimide (CMPI) films coated on silicon wafer. CMPI undergoes a fast photolysis under UV light. So, in the case of pattern fabrication on CMPI it is possible to fabricate patterns without development process. Possibilities for SMPI to be applied to nano-scale patterns fabrication were demonstrated. Compared to usual lithographic processes, the process proposed in this work is simple because development, one of steps to fabricate nano-scale patterns, is not needed. And the finite-difference-time-domain (FDTD) method was employed to simulate the energy intensity distribution in the near-field. The simulation was executed for NSOM tip and UV laser. The influence of aperture size and tip-sample distance on the resolution of the lithographic process is discussed from the simulation results. Comparison of some simulation results with corresponding experimental results could confirm the validity of the simulation model proposed.