具有大面积均匀性、高质量的大尺寸中阶梯光栅铝膜的研究

大尺寸中阶梯光栅具有大孔径和极高的衍射级次,可以实现普通光栅难以达到的极高光谱分辨率,而制备大面积均匀性的高质量铝膜是实现高性能大尺寸中阶梯光栅的关键因素.本文首次详细报道了具有大面积均匀性、高质量的大尺寸中阶梯光栅铝膜的制备工艺.首先通过理论计算模拟了蒸镀过程中蒸发源的位置、发射特性以及夹具高度对铝膜均匀性的影响,然后研究了关键的蒸发工艺参数,例如蒸发速率、蒸发高度等对铝膜均匀性和铝膜质量的影响,最后在最佳化的蒸发工艺条件下,成功制备出满足大尺寸中阶梯光栅用的在直径700 mm范围内的均匀性小于1%、厚度大于10μm的高质量铝膜.     

Mo/Si软X射线多层膜中厚度均匀性的精细控制

为了获得光学性质均匀的大面积软X射线多层膜,必须控制好周期结构中单层膜的厚度均匀性。为此建立了磁控溅射薄膜沉积技术中单层膜厚度均匀性的分析和控制模型,解释了基底变速转动法可用来获得膜厚均匀的多层膜,并根据理论分析获得了基底的变速路径。将其应用于基底公转速度变速法来制备均匀性可控的大面积Mo/Si软X射线多层膜。小角X射线衍射测试结果表明,采用优化后的变速路径制备的多层膜,样品不同位置的各级次衍射峰位都能很好吻合,说明多层膜的周期厚度基本一致。计算表明该方法在直径200mm范围内可将周期结构中Mo层的不均匀性从20.6%修正到1.1%,Si层的不均匀性从27.0%修正到1.6%。     

均匀软X射线多层膜制备方法研究

 介绍了基于速度调制技术的均匀软X射线多层膜制备方法，并采用该方法在直径为150mm的平面硅基板上制备出Mo/Si多层膜，其中心波长为13.5nm，膜厚空间非均匀性优于1％，较转盘匀速溅射方法制备的多层膜膜厚空间均匀性提高了近6倍。     

膜厚监控误差及监控片不均匀对膜厚监控的影响

借助于VC 编程从理论上模拟分析了膜厚监控误差以及监控片不均匀性对光学膜厚监控的影响。结果表明,膜厚监控误差和监控片的不均匀性都对监控曲线有影响;随着膜层层数的增加,监控片不均匀性逐渐增大。实验制备了多层规整薄膜并对其监控曲线进行了分析,分析表明考虑到膜厚监控误差和监控片不均匀性后计算的光学监控曲线和镀膜过程实测光学监控曲线吻合较好。这说明膜厚监控误差和监控片不均匀性是引起监控曲线与理论值偏离的重要因素。介绍了如何计算考虑膜厚监控误差和监控片不均匀性后的理论监控曲线。这将对膜厚自动监控,尤其是对非规整膜系的自动监控具有重要的指导意义。     

大口径光学元件薄膜厚度均匀性修正

 研究了2.2 m高真空箱式镀膜机镀膜时的实际膜厚分布情况。对非球面和平面光学元件，分别采用行星夹具和平面公转夹具并利用修正板调节膜厚均匀性。从实验上实现了大口径薄膜均匀性的调节，并获得较为理想的结果。口径在700 mm范围内，对于凹面均匀性可以控制在0.7%以内，平面均匀性在1%以内；口径在1 200 mm范围内凹面元件均匀性可控制在1%以内，平面1 300 mm口径以内窗口均匀性可控制在1%以内。镀制了口径在400~1 300 mm的多种天文观测上使用的反射镜、增透膜等，获得了理想的光谱曲线与较好的使用效果。     

用于软X射线激光实验的铝衰减膜的测量

对不同方法制备的不同厚度的铝衰减膜,用微机控制α测厚仪测量了膜的质量厚度以及膜厚均匀性,用Auser电子能谱(AES)对铝膜进行了组分的表面和深度分布分析,根据铝KLL Auger特征谱揭示了氧化膜的化学组分并测量了氧化膜厚度随放置时间的变化,还讨论了膜中其它杂质含量的上限。     

凹球面涂布光刻胶均匀性研究

通过对离心法在凹球面上涂布光刻胶过程进行分析,阐明了离心状态下光刻胶在凹球面基底上的流动机理,结合试验提出影响凹球面涂布光刻胶膜厚均匀性的主要因素有胶液粘度、旋涂速度、旋涂时间,列举了以上因素引起的各种现象,并进行了理论分析。引用凹球面旋涂光刻胶的膜厚公式,建立了膜厚与速度关系数学模型;利用流体力学原理解释了有限圆形空间中流体速度对膜层均匀性的影响,从而解决了大曲率凹球面上制备微细图形结构的关键工艺问题,对非球面上制备微细图形具有借鉴作用。     

真空紫外波段铝反射膜制备

为制备出在130～210nm波段具有良好光谱性能的铝反射膜,优化设计了铝反射镜中铝层和保护层氟化镁的厚度,理论确定铝层和氟化镁保护层最佳厚度分别为80nm和33nm。采用热舟蒸发工艺,在BK7基片上制备了Al反射膜样品,获得了130～210nm波长范围内反射率均大于80%的金属铝膜。研究了铝层沉积速率和紫外辐照处理对薄膜性能的影响,并考察了铝膜光谱性能的时效性。结果表明铝层沉积速率越快,制备的铝膜反射率越高;合理地存放铝膜元件,可以长时间内保持铝膜的光谱性能。适当的紫外辐照处理能进一步提高铝膜在真空紫外波段的反射率。     

激光沉积大面积均匀薄膜数学模型与实验

由于激光烧蚀靶材产生的等离子体呈高斯分布,其中所包含粒子密度及性能的空间分布极不均匀,因此脉冲激光沉积法难以制备性能与膜厚均匀的大面积薄膜。提出并构建了衬底自转与一维变速平移机构,衬底匀速自转的同时,进行一维平移,越靠近等离子体中心平移速率越大、反之越小,达到均匀镀膜的目的;在此基础上建立了机构运动参数对膜厚影响的数学模型,通过仿真模拟分析关键参数对膜厚分布的影响;通过运动参数优化指导实验,最终获得了直径为200mm、不均匀性不超过±4%的大面积类金刚石膜,与仿真优化结果吻合。     

AlxGa1-xN晶体薄膜中铝含量的卢瑟福背散射精确测定

采用金属有机化合物气相淀积法在(0001)取向的蓝宝石衬底上生长一层 大约20 nm厚的AlN缓冲层, 在缓冲层上生长大约2 μm厚、 晶体质量良好的Al_xGa_1-xN外延层, 通过深紫外光致发光法测量发光峰的能量E_g 判断外延层中铝含量的均匀性, 取样品均匀性良好的氮铝镓外延片进行卢瑟福背散射(RBS)实验, 通过两个高能离子束实验室分别进行RBS随机谱分析, 每个实验室测量六个样品, 由分析软件拟合随机谱获得外延层中的x_Al. 并对样品的均匀性、堆积校准、计数统计、散射角、离子束能量与阻止截面 等影响测量结果准确性的不确定度来源进行分析. 结果表明, 采用入射离子⁴He, 能量为2000 keV, 散射角为165° 时, 氮铝镓外延片中铝含量(x=0.8) 的测量不确定度为2.0%, 包含扩展因子k=2. 关键词： 氮铝镓 卢瑟福背散射 测量不确定度 金属有机化合物气相淀积法     

多波段高功率激光扩束系统设计

 对透射式和反射式扩束系统应用于高功率激光扩束的优缺点进行了对比研究。采用次镜为凸抛物面,主镜为凹抛物面的无焦卡塞格林系统,运用ZEMAX光学设计软件,按激光扩束系统的扩束倍率和系统的波像差要求,设计出多波段高功率激光扩束系统。对用于高功率激光反射镜的基底材料进行分析,选用无氧铜作为基底材料;采用金增强的膜系设计,膜系从近红外到远红外宽光谱波段激光的反射率均在98%以上。面形精度均方根值优于λ/40(λ=0.632 8 μm)的平面镜作为基准镜,采用光学干涉方法对设计的激光扩束系统进行检测实验,结果表明：该扩束系统的扩束倍率为3.53,波像差为0.206λ,满足多波段高功率激光光束发射要求。     

Studies on adhesion characteristics and corrosion behaviour of vinyltriethoxysilane/epoxy coating protective system on aluminium

The corrosion stability of vinyltriethoxysilane/epoxy coating protective system on aluminium is strongly related to the strength of bonds forming at the metal/organic coating interface. This article is a study of adhesion, composition, electrochemical and transport properties of epoxy coatings electrodeposited on bare aluminium and aluminium pretreated by vinyltriethoxysilane (VTES) during exposure to 3% NaCl. The VTES film was deposited on aluminium surface from 2% vinyltriethoxysilane solution during 30 s. From the values of adhesion strength (pull-off test), time dependence of pore resistance and coating capacitance of epoxy coating (impedance measurements) and diffusion coefficient of water through epoxy coating (gravimetric liquid sorption measurements), the influence of VTES sublayer on the corrosion stability of the electrodeposited epoxy coating was shown.The work discusses the role of the VTES pretreatment in the enhanced adhesion and corrosion stability of epoxy cataphoretic coating. The electrochemical results showed that the aluminium pretreatment by VTES film improved barrier properties of epoxy coating (greater pore resistance and lower coating capacitance). The lower value of diffusion coefficient of water through epoxy coating indicates the lower porosity, while the smaller adhesion reduction points to better adhesion of epoxy coating on aluminium pretreated by VTES film. The composition of the deposited coatings investigated by XPS enabled the clarification of the bonding mechanism.     

Back-side-coated chirped mirrors with ultra-smooth broadband dispersion characteristics

We demonstrate a new technique for the design of chirped mirrors with extremely smooth dispersion characteristics over an extended ultra-broadband wavelength range. Our approach suppresses spectral dispersion oscillations, which can lead to unwanted strong spectral modulations and limit the bandwidth of mode-locked laser pulses. Dispersion oscillations are significantly reduced by coating the chirped mirror structure on the back side of a substrate, providing ideal impedance matching between coating and ambient medium. An anti-reflection coating may be added on the front side of the substrate, geometrically separated from the chirped mirror. The chirped mirror structure and the anti-reflection coating are non-interfering and can be independently designed and optimized. The separation of both coating sections provides a much better solution for the impedance-matching problems than previous approaches to chirped mirror design. We show by a theoretical analysis and numerical simulations that minimum dispersion oscillations are achieved if the index of the substrate is identical to the index of one of the coating materials and if double-chirping is used for the chirped mirror structure. Based on this analysis, we design a mirror that supports a bandwidth of 220 THz with group delay dispersion oscillations of about 2 fs² (rms), an order-of magnitude improvement compared to previous designs of similar bandwidth. In a first experimental demonstration of back-side-coated (BASIC) mirrors, we achieve nearly transform-limited and virtually unchirped pulses of 5.8 fs duration from a Kerr-lens mode-locked Ti:sapphire laser. BASIC mirrors are particularly suited for higher-order dispersion compensation schemes. They support the extremely broad spectra of few-cycle pulses and promise to provide clean pulse shapes in this regime. Received: 19 April 2000 / Published online: 6 September 2000     

Current-controlled curvature of coated micromirrors

Precise control of micromirror curvature is critical in many optical microsystems. Micromirrors with current-controlled curvature are demonstrated. The working principle is that resistive heating changes the temperature of the micromirrors and thermal expansion induces a controlled curvature whose magnitude is determined by coating design. For example, for wide focal-length tuning, the radius of curvature of a gold-coated mirror was tuned from 2.5 to 8.2 mm over a current-induced temperature range from 22 degrees to 72 degrees C. For fine focal-length tuning, the radius of curvature of a dielectric-coated (SiO2/Y2O3 lambda/4 pairs) mirror was tuned from -0.68 to -0.64 mm over a current-induced temperature range from 22 to 84 degrees C. These results should be readily extendable to mirror flattening or real-time adaptive shape control.     

望远镜主镜气压力驱动器设计

为了获取优异的光学图像质量,大口径天文望远镜通常采用主动支撑结构以校正主镜面形误差。对望远镜主镜支撑系统所需的气压驱动器进行了研究。基于气动原理设计了一种采用滚动膜片结构的气压力驱动器,其中滚动膜片结构用于消除摩擦力的影响,滚珠式力解耦器用于消除侧向力、弯矩的影响。进一步设计了针对气压驱动器带死区的比例-积分-微分(PID)控制算法,以实现对气压驱动器的闭环控制。实验结果表明:气压力驱动器可精确提供主镜控制所需的支撑力,在望远镜高角变化速度达到2°/s时,输出支撑力范围为0～1000N,驱动器支撑力误差仅为满量程的±0.4%。设计的气压驱动器可实现主动支撑力的快速精确输出,能满足天文望远镜主镜主动支撑需求。     

金属基及涂层表面粗糙度的测量方法研究

本文用干涉显微镜法，触针法，总体积分散身镜向反射光强法对未抛光铝基。抛光微粗糙铝基，微粗糙不锈钢基，微粗糙钢基和涂漆表面的粗糙度进行了实验测量和对比分析，从粗糙面激光散射角度讨论了各种方法的适用范围和局限性。     

Infrared antireflective filtering for extreme ultraviolet multilayer Bragg reflectors

An extreme ultraviolet multilayer mirror with an integrated spectral filter for the IR range is presented and experimentally evaluated. The system consists of an IR-transparent B4C/Si multilayer stack which is used both as EUV-reflective coating and as a phase shift layer of the resonant IR antireflective (AR) coating. The AR coating is optimized in our particular case to suppress CO2 laser radiation at a wavelength of 10.6 μm, and a suppression of more than two orders of magnitude is demonstrated. The method allows high suppression over a large angular acceptance range, relevant for application in lithography systems.     

狭缝宽度与取样间隔对镶嵌铜多孔铝膜透射光谱的影响

用阳极氧化的方法制备了阳极氧化铝膜，向其孔中镀入了铜，制备了镶嵌铜多孔铝膜。为了研究狭缝宽度与取样间隔对其透射光谱的影响，利用岛津UV－3101型分光光度计，测得了相同取样间隔不同狭缝宽度和相同狭缝宽度不同取样间隔情况下镶嵌铜多孔铝膜的透射光谱，并分析了狭缝宽度和取样间隔对透射曲线的影响，得到了测试镶嵌铜多孔铝膜所需合适的狭缝宽度和取样间隔。测试结果表明：对镶嵌铜多孔铝膜而言，在可见光波段选择3nm的狭缝宽度和0.5nm或1nm的取样间隔为宜；在近红外波段选择5nm或8nm的狭缝宽度和2 nm的取样间隔为宜。     

空间光学遥感器主反射镜轻量化及支撑设计

为了得到某空间光学遥感器主反射镜合理的结构及支撑方式，检验新型光学材料SiC的光学性能，尤其是应用于空间光学系统的可行性，通过建立该空间光学遥感器主反射镜组件的虚拟样机，采用有限元仿真的方法，分析主反射镜在背部采取不同形式轻量化情况下的质量及质心位置。建立几种主反射镜的有限元模型，采用合理的MPC约束边界条件，用有限元方法分析主反射镜在加工、测试状态下自身重力作用对反射面面形精度的影响。经过仿真比较及轻量化优化设计，得到一种主反射镜及支撑的合理化结构，轻量化率达到75.6%，反射镜面RMS值为12.53nm，Pv值为54.52nm。最后的分析结果表明：质量、刚度及反射镜面精度均满足工程要求。