极紫外与软X射线用非晶碳膜全反射镜的研究

用高真空磁控溅射设备分别在工作气压为0.40Pa和0.67Pa下制备了非晶碳膜全反射镜样品,利用X射线掠入射反射测量了膜层厚度、粗糙度和膜层密度,用原子力显微镜测量了样品的表面粗糙度,用同步辐射测量了不同工作气压下制备的非晶碳膜全反射镜的反射率,并对测量结果进行了分析讨论.测试结果表明:在0.40Pa工作气压下制备的非晶碳膜反射镜的性能优于在0.67Pa工作气压下制备的反射镜的性能,在掠入射角小于4.5°时,非晶碳膜全反射镜在5nm以上波段有比较平坦的高反射率,在波长小于5nm波段,反射率急剧下降.     

中红外光参变振荡器在高反射率测量中的应用

根据光腔衰荡光谱技术(CRDS)原理,使用中红外光参变振荡器(OPO)为光源建立了直腔与折叠腔相结合的中红外波段3.6 μm 反射率测量实验装置,用于研究中红外波段的高反射膜反射率,测试精度为10-4。使用直型衰荡光腔测试了三对不同薄膜材料设计镀制的高反射腔镜的反射率,并选择了一对腔镜用于实验装置中。采用该装置精确测试了不同薄膜材料镀制的高反射膜的反射率,包括YbF3/ZnS,YbF3 /ZnSe多层膜,以及由银加保护膜镀制的反射镜。研究表明,中红外波段介质膜的反射率可达到R>0.9990,其中由YbF3/ZnSe镀制在硅基底上的多层介质膜3.6 μm反射率可达到99.96％。     

激光等离子体光源软X射线反射率计

介绍了所研制的激光等离子体光源软X射线反射率计,该反射率计由激光等离子体光源、掠入射光栅单色仪、样品室、真空系统、样品台、光电探测系统和计算机控制系统组成,工作波段8～30 nm,测量样品的最大尺寸为130 mm×120 mm×120 mm(长×宽×高),可以利用这台反射率计对软X射线波段光栅、滤光片和多层膜反射镜等光学元件进行测量和评估。为检验反射率计的性能指标,利用该反射率计对本室研制的软X射线多层膜反射镜的反射率进行了测量,测量结果与理论计算结果符合较好,反射率测量重复性为±0.6%。     

逆向热蒸发制备望远镜主镜银反射膜

以自上向下热蒸发大型镀膜机为实验平台,开展了逆向蒸发制备大口径银反射镜研究.通过设计特殊蒸发舟及优化相关工艺参数,实现了金属银膜稳定、高速向下蒸发.根据逆向热蒸发工艺特点,选取熔点低、升华型材料Cr和SiO及特殊设计的蒸发舟,以Cr或CrNx为粘结层,SiOx或SiOxNy为保护层,制备了三种具有四层结构的介质保护性银反射膜,并对所制备反射镜样品的反射率、断面形貌和环境稳定性进行了表征.实验结果表明:膜系结构为3 nmCr/120 nmAg/0.6 nmCrNx/150 nmSiOxNy的银反射膜具有较好的环境稳定性和光谱特性;通过了24小时湿热实验(50℃/相对湿度98％/)和盐雾实验,在400～1 800 nm波段光谱范围内,银反射膜的平均反射率达到97.8％.     

中红外DF激光系统宽光谱反射膜的设计与实验测量

报道了目前所做的确定DF激光系统各种宽光谱反射膜性能特性的工作。利用制备的介质金属增强反射镜,由实验获得了DF激光波长为3.8μm时反射率大于99.4％、可见光区和8～14μm红外区平均反射率高于95％的结果。为说明这些反射镜性能,进行了反射率测量和环境试验。     

逆向热蒸发制备望远镜主镜银反射膜（英文）

以自上向下热蒸发大型镀膜机为实验平台,开展了逆向蒸发制备大口径银反射镜研究.通过设计特殊蒸发舟及优化相关工艺参数,实现了金属银膜稳定、高速向下蒸发.根据逆向热蒸发工艺特点,选取熔点低、升华型材料Cr和SiO及特殊设计的蒸发舟,以Cr或CrN_x为粘结层,SiO_x或SiO_xN_y为保护层,制备了三种具有四层结构的介质保护性银反射膜,并对所制备反射镜样品的反射率、断面形貌和环境稳定性进行了表征.实验结果表明:膜系结构为3nmCr/120nmAg/0.6nmCrNx/150nmSiO_xN_y的银反射膜具有较好的环境稳定性和光谱特性;通过了24小时湿热实验(50℃/相对湿度98%)和盐雾实验,在400~1 800nm波段光谱范围内,银反射膜的平均反射率达到97.8%.     

4.48 nm正入射软X射线激光用Cr/C多层膜高反射镜的研制

针对4.48nm类镍钽软X射线激光及其应用实验,设计制备了工作于这一波长的近正入射多层膜高反射镜。选择Cr/C为制备4.48nm高反射多层膜的材料对,通过优化设计,确定了多层膜的周期、周期数以及两种材料的厚度比。模拟了多层膜非理想界面对高反射多层膜性能的影响。采用直流磁控溅射方法在超光滑硅基片上实现了200周期Cr/C多层膜高反射镜的制备。利用X射线衍射仪测量了多层膜结构,在德国BessyⅡ同步辐射上测量了在工作波长处多层膜反射率,测量的峰值反射率达7.5%。对衍射仪测量的掠入射反射曲线和同步辐射测量的反射率曲线分别进行拟合,得到的粗糙度和厚度比的结果相近。测试结果表明,所制备的Cr/C多层膜样品结构良好,在指定工作波长处有较高的反射峰,达到了设计要求。     

共口径中波/短波偏振红外成像光学系统

对中波/短波偏振红外成像光学系统进行了研究,设计了一个新颖的共口径中波/短波偏振红外成像光学系统.该光学系统由全反射式无焦光学系统、分束镜、二级镘远系统、偏振组件和红外物镜系统组成,为了约束主反射镜、双面反射镜、分束镜和偏振片的H径,创造性地采用了_三次成像光学系统.光波经无焦光学系统后被分束镜分成中波红外波段(3～5 gm)和短波红外波段(1～2.5弘m).然后分别经两个物镜系统会聚到两个探测器上.实现了双波段共1:3径成像.给出了光学系统的设计结果.像质良好,满足整机使用要求.     

大口径像旋补偿系统的分析与设计

由成像系统和可控扫摆镜组合的具有周视功能的系统常出现像旋现象,根据反射棱镜具有调整光轴和引起像旋的性能,将不同的组合结构设计成像旋补偿系统,以相互抵消的方式来消除像旋的影响。利用平面反射镜组合代替反射棱镜的方式,消除棱镜加工等实际因素对通光口径的限制。根据反射棱镜转动定理分析扫摆镜产生像旋的原因,举例说明反射镜组合能够解决大口径扫摆光学系统的像旋问题。     

光电测量仪器中玻璃微珠反射板的研制

研制了高反射率的玻璃微珠,并制成了玻璃微珠反射板,可替代光电测量仪器中使用的普通平面反射镜。借助于玻璃微珠的正向反射特性,克服了普通平面反射镜由于环境振动导致反射镜振动引起的测量精度下降的缺陷,确保了在动态测量时光学系统的稳定性和测量的精确性。     

透红外冷反射镜的研制

本文介绍一种透红外冷反射镜反光杯（碗）的光学设计、光学薄膜膜系设计和镀制工艺，特别介绍了镀制工艺中膜层的均匀性、冷光膜的重复性、牢固性等影响因素和解决办法。透红外冷反射镜采用复杂的多层膜系，具有极为有用的光学性质，对可见光高反射，对红外光则有７５％以上的透射，因而得到了实际应用。     

COIL用变形反射镜介质反射膜

 报道COIL激光用变形反射镜的介质反射多层膜实验。在真空镀膜机内制备了膜系Sub/Ag(SiO₂/HfO₂)⁴/air和Sub/Ag(YbF₃/ZnS)³/air, 反射率分别为99.90%和99.87%。在经历109次循环后变形镜物理特性无变化。研究了COIL激光辐射下热畸变和损伤特性。分别在功率密度为1.52kW/cm²和1.18kW/cm²的COIL激光辐照下,这两种膜系的变形镜波前变化为0.37l 和0.54l 。因此对于变形镜1kW/cm²激光功率密度是安全可靠的。     

Interaction of intense IR laser radiation with a-C:H protective coatings

The results of a determination of the optical breakdown thresholds of air near the surface of copper laser mirrors with a-C:H protective coating by intense pulsed 10.6 μm radiation are analyzed and systematized. It is shown that there is no correlation between the breakdown threshold of a coated mirror, the reflectance of the coating, and the breakdown threshold of the initial copper surface. Experimental dependences of the threshold of optical breakdown of coated mirrors on the a-C:H thickness and deposition rate as well as the storage time of the mirrors are given. Estimates are made of the rise in the surface temperature in the irradiation zone for the case of an ideal adhesive contact and calculations are made of the damage threshold of the coating in the case that the adhesive contact between the mirror and the coating is impaired. The effect of the a-C:H coating properties and the conditions at the polished metal surface-protective coating interface on the optical breakdown threshold is discussed. Zh. Tekh. Fiz. 68, 59–66 (September 1998)     

双变形镜自适应光学系统像差解耦研究

对由大行程变形镜和高空间频率变形镜组成的双变形镜自适应光学系统中的像差解耦原理和限定像差校正算法做了理论分析。认为在高空间频率变形镜的斜率响应矩阵中加入限定像差向量,根据直接斜率法分别计算出两个变形镜的控制电压,可以实现两个变形镜分别对低阶像差和高阶像差的闭环校正。仿真研究了19单元变形镜和61单元变形镜组成的双变形镜自适应光学系统对低阶像差和高阶像差分别校正的情况,结果说明双变形镜自适应光学系统的校正效果与理想行程的单变形镜自适应光学系统的校正效果相当,避免了制作同时具有大行程和高空间频率两个特征的变形镜。     

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。     

中红外2μm KTA光参量振荡器的输入镜膜层损伤分析

对基于KTA(KTiOAsO4,砷酸钛氧钾)晶体的中红外2μm光参量振荡器的输入镜膜层损伤现象进行了初步分析及对比实验研究,表明薄膜缺陷导致的热效应是造成输入镜膜层损伤、抗损伤阈值低的主要原因,同时发现由于腔镜失调等原因造成的腔内残余1.06μm激光是造成膜层损伤的主要来源,这些结果对改进光参量振荡器系统设计、进一步提高2μm激光输出能量具有一定的指导作用。     

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。     

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     

Study of the reflectivity in the XUV domain of normal-incidence multilayer mirrors

Summary The development of multilayer optics has profound implications for soft-X-ray/UV astronomy, since it allows to extend the use of normal-incidence telescopes to cover the XUV region where lines are formed at greatly different temperatures (10⁵–10⁷ K). A multilayer mirror consists of alternating thin layers of suitable materials deposited on a substrate and its performance depends not only on the optical properties of the materials but also on the design of the multilayer. In this study we have computed the reflectivity of multilayer mirrors to select both the materials and the multilayers design to achieve the best performance in the wavelength range from 30 to 350 ?. Our calculations show that high theoretical reflectivities, from 0.2 to 0.8 and relatively narrow bandpasses, from ∼ 1? to ∼30 ?, can be obtained, in the wavelength range from 30 to 350 ?, by a suitable choice of the materials and of the multilayer design.     

Design of axisymmetric multi-mirror grazing incidence system to increase the numerical aperture of neutron and X-ray microscopes

An axisymmetric multi-mirror system for neutron and X-ray microscopes is proposed to increase their numerical aperture and collection efficiency. A Wolter type-I mirror is used as the basis of the multi-mirror system at grazing incidence. The addition of an even number of hyperboloid mirrors to the Wolter type-I mirror can satisfy both an equal optical path length and Abbe’s sine condition. The numerical aperture increases in proportion to the number of mirrors. The optical parameters of the system with four tandem mirrors are calculated for neutrons and X-rays with a wavelength of 0.4 nm by assuming that the average grazing angle of incidence is 5.4 mrad and the magnification is 10. The inner diameters of the mirrors are limited to <10 mm considering the total length of the optical system. Tolerance of off-axis distance was calculated using a ray-tracing computer simulation. Ray tracing shows that a blur size <14 nm will be possible at an off-axis displacement of 10 μm.