近红外宽截止窄带滤光膜的研制

在空间光通信系统中,为满足光学系统对滤光膜的特殊要求,研制出了一种近红外宽截止窄带滤光膜,实现了降低深背景范围内杂散光干扰的要求.通过对薄膜材料特性的研究、膜系设计曲线的不断优化,得到了相对易于制备的窄带滤光膜结构;采用电子束加热蒸发及离子辅助沉积技术制备薄膜,采用光控加晶控同时监控的方法监控膜层厚度,通过不断优化工艺参量,提高中心波长处的透过率,最终成功得到了光谱性能较好的滤光膜.经光谱测试表明:所镀膜层在800~1 530nm、1 600~1 800nm波段平均透过率低于0.3%,1 565nm单点透过率高于92%,通带半带宽为18nm,满足光学系统的使用要求.     

用超薄金属膜和不对称法布里—珀罗干涉滤光片设计窄带高反膜

提出利用ｎ≈ｋ的金属膜层材料设计窄带反膜的一种新方法－用超薄金属膜与不对称法布里－珀罗干涉滤光组合设计法，给出了可光光区窄带高反膜的膜系结构，定量地分析了膜系的反射率，反射峰值，反射半波带宽光谱反射特性，实验证实了理论设计和分析，同时，也提供了设计非可见光波段的窄带高反滤光片的方法。     

含n＝k超薄金属膜的周期对称膜系的性质及窄带高反膜设计

本文阐述了n≈k的超薄金属膜与介质膜组成周期对称膜系的光学特性,并结合Ag、Al等膜层的高反特性提出了可见光区诱导窄带高反膜系结构,推导出膜系的反射率、反射峰值、反射半波带宽等光谱反射特性的近似公式,实验证实了理论设计和分析.同时也提出了设计红外和紫外窄带高反滤光片的方法.     

1 064, 532和680 nm波长的反射-吸收复合型防护膜的研制

 针对1 064, 532 和 680 nm波长激光， 以聚碳酸酯 （PC） 为镀膜基底， 钕玻璃激光中心波长为1 064 nm, 采用六分之一加三分之一膜系的反射膜系设计，以氧化锆为高折射率膜层材料，氯化酞菁铝掺杂的氧化硅为低折射率膜层材料，通过溶胶-凝胶法镀21层膜，并在多层反射膜与PC基底之间插入张力匹配层，实现了钕玻璃激光器1 064 nm主频和532 nm二倍频波长激光的反射，以及680 nm波长红宝石激光的同时吸收，1 064,532和680 nm波长处的透射率分别为1.67％，18.24％和2.4％。     

新型小尺寸窄带偏振分光器在光纤通信中的应用

在光纤通信中,为了在不改变调制波长范围的基础上仍能实现更多数据通道的波分复用,设计了一种新型的小尺寸窄带偏振分光器,用于对现有的数据通信网络进行扩容以及提高光信号的信噪比。在该分光器上蒸镀了两种新设计的膜系,一层是窄带滤光膜,另一层是偏振分光膜。采用TFCalc软件仿真,设计结果中窄带滤光膜的带宽约为0.4 nm,偏振分光膜在1 530～1 560 nm范围内对p光的通透性能优于99.8%。基于以上膜系设计在BK7光学玻璃上实际制备两组膜系,实验采用Agilent 8164-A型光波测量系统对经过膜后的光进行光谱分析。结果显示,窄带滤光膜的实际带宽优于0.4 nm,增益平坦度小于-0.05 dB,相比现有常见的0.8 nm滤光膜具有更窄的带宽,可以实现在调制波长范围不变的条件下增大波分复用的数据通道总量。偏振滤光膜的实际p光透光率为99.6%,相比仿真值略低,但仍优于设计要求,相比传统分光器的光信号强度保留效果更好,具有更高的信噪比。综上所述,该分光器具有更好的应用价值和实用意义。     

用超薄金属膜和不对称法布里－珀罗干涉滤光片设计窄带高反膜

提出利用ｎ≈ｋ的金属膜层材料设计窄带高反膜的一种新方法用超薄金属膜与不对称法布里－珀罗干涉滤光片组合设计法。给出了可见光区的窄带高反膜的膜系结构；定量地分析了膜系的反射率、反射峰值、反射半波带宽等光谱反射特性。实验证实了理论设计和分析。同时，也提供了设计非可见光波段的窄带高反滤光片的方法     

121.6 nm远紫外高反射薄膜研究

远紫外波段高反射薄膜的研究具有重要应用价值。为了实现高反射率,采用高温三步蒸发法沉积MgF_2膜以保护Al膜,制备了远紫外宽带高反射薄膜,并对样品进行退火处理。结果显示,改进制备工艺和退火工艺后,紫外宽带高反射薄膜在121.6 nm处的反射率高达90%,接近理论设计值。同时分析了散射损耗的影响。采用优化的LaF_3/MgF_2膜系结构,制备了窄带反射滤光薄膜,其在中心波长122.5 nm处的峰值反射率为75%且半峰全宽为8 nm,达到了理论设计的预期效果,但退火处理损伤了薄膜表面,散射损耗增加,薄膜反射率下降。     

缓冲层对导模共振滤光片反射光谱截止特性的影响

提出将均质多层膜系设计中的缓冲层概念71入到反射导模共振(GMR)滤光片的设计中,通过严格的耦合波理论精确计算,研究了加入缓冲层对改善导模共振滤光片反射峰边带截止深度及截止宽度的作用.双层导模共振滤光片结构中,入射光为TE偏振光时,设计增加97.5 nm缓冲层后,能够明显地展宽反射光谱范围.由原来的192.4 nm展宽到345.6 nm,并且在650～1250 nm波长范围内的边带截止度均比不含缓冲层结构的要深.入射光为TM偏振光,以类似TE结构的滤光片在布儒斯特角入射时,在700~1300 nm波长范围内,较不含缓冲层的结构,也能够获得更宽的截止带反射光谱和更深的截止度.在提出的膜系结构中,经过优化膜系、选择合适的光栅参数等,可以使反射光谱具有更好的截止特性,同时保证设计的共振峰位置不变.     

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。     

中心波长14.95μm超窄带滤光片的研制

讨论了大气探测红外分光辐射计第1光谱通道超窄带滤光片的研制情况。采用富碲碲化铅材料作为高折射率膜层材料,通过控制沉积速率、沉积温度、真空度等工艺参数,镀制的膜层具有小的自由载流子浓度,整个膜系具有低的光吸收和高的透射能量。研制出入射光束半锥角Φ为18°时,中心波长14.95μm、带宽0.065μm、相对带宽小于0.5%的长波CO2超窄带滤光片。该超窄带滤光片已实现空间应用5年,在天气预报数据获取中工作稳定。     

Study of a narrowband reflection filter with multi-channels

Reflection filters have various applications in optical communication and other systems.In this letter,we propose a narrowband high-reflection filter composed of dielectric and metallic layers,in which an optimized filter combined with an admittance-matching layer with broad stop band is achieved.The structure can be expressed as Sub ｜ （HL）13H2L（HL）313Cr0.84H ｜ air,with full-width at half-maximum （FWHM） bandwidth of 2.5 nm.Based on this structure,reflection filters with multi-peaks are presented,and the law of distribution of peak positions is drawn.     

Short wave pass and long wave pass dichroic coating at 45° on zinc selenide substrate for dual band thermal imager

In dual band thermal imager dichroic coating plays a vital role in separating 3–5 μm and 7.5–10.5 μm wavelength region for observing better image quality from two different channels. In this work a study has been carried out on the design and fabrication of short and long wave pass dichroic coating at 45° on zinc selenide flat substrate. These dichroic coated optics can be used to separate 3–5 μm (in reflection or transmission channel) and 7.5–10.5 μm (in transmission or reflection channel) wavelength region. An inhomogeneous refractive index profile which is a polynomial of 5th order was considered to design the high and low wave pass dichroic coating on zinc selenide substrate. The inhomogeneous profile was then approximated with five steps from substrate to air medium. These steps were then converted in terms of durable coating materials of six and seven layer stack for short and long wave pass dichroic coating respectively. The coating material combination used was germanium as high index material and IR-F625 as low index material. Result achieved for short wave pass dichroic filter was 94% average transmission in 3–5 μm region and 95% average reflection in 7.5–10.5 μm region. Similarly, result achieved for long wave pass dichroic filter was 95% average reflection in 3–5 μm region and 94% average transmission in 7.5–10.5 μm.     

实现全反射镜功能的光子晶体禁带特性

用传输矩阵法研究一维光子晶体G(AB)mC(AB)mH的能带特性及电场分布,结果发现:随着m的增大,在830—883nm波长范围内,光子晶体G(AB)mC(AB)mH禁带中的导带透射率逐渐趋于零,即光被禁止通过,实现全反射镜功能,且随着入射角的增大,光子晶体的禁带逐渐向短波方向移动。随着介质层G、H的折射率增大,光子晶体在833.6—879.1nm波长范围内出现大的禁带,亦实现全反射镜功能。光子晶体G(AB)5C(AB)5H内部存在很强的局域电场,即在光子晶体内传输的光,被强烈局域在禁带范围内,并在缺陷层C处达到极大值,而且随着m的增大,局域强度增强。这些光学传输特性,为研究、设计新型光学器件全反射镜、滤波器等提供指导。     

飞秒激光对高反膜的破坏及其超快动力学过程

研究了800nm飞秒激光照射下45°高反膜ZrO2-Si O2的破坏及其超快动力学过程。利用原子力显微镜和扫描电镜观察了材料的烧蚀形貌,测量了破坏阈值与脉冲宽度、烧蚀深度与脉冲能量的依赖关系。随着脉冲宽度从50fs增加到900fs,其烧蚀阈值从0.35J/cm2增加到1.78J/cm2。烧蚀深度与激光能流密度近似成对数关系。当激光强度略高于烧蚀阈值时,材料很快被烧蚀到几百纳米,烧蚀深度表现出明显的层状特性。同时,利用建立的抽运探针实验系统,测量了高强度抽运脉冲作用下材料对探针光的反射率随延迟时间的变化,揭示了薄膜烧蚀的超快动力学过程。实验结果表明高反膜表层的材料对烧蚀特性有重要影响。     

Transmission characteristics of multilayer films composed of electro-optic and dielectric materials

We describe the theoretical evaluation for the transmission characteristics of multilayer films composed of periodic electro-optic and dielectric materials in a variable electric field. The films are assumed to have cavity-type layer stacking structures, which work as a narrow bandpass filter, and their electro-optic material is uni-axial BaTiO₃, whose electro-optic coefficient r₅₁ is larger than 1300 pm/V. The evaluation indicates that films composed of BaTiO₃ and SiO₂ or MgO function as tunable optical bandpass filters, with a tunable range larger than 6 nm for an electric field of less than 4 V/μm.     

激光辐射致热单层薄膜温度响应

用热传导方程计算了在脉宽10ns、波长1.06μm的激光辐射下,TiO_2单层膜的温度场分布.结果表明:膜层的热参数增大,其峰值温度明显降低,而基板热参数变化对膜层温度响应影响很小,温度场分布由电场分布决定,1/4波长薄膜的峰值温度低于半波长薄膜的峰值温度.     

Feasibility analysis of solid immersion lens-based dual-layer near-field recording optics with a numerical aperture of 1.84

A dual-layer near-field recording (NFR) optical system with a high numerical aperture (NA) of 1.84 was designed by appropriate cover and spacing layer selection, using layers with refractive indices of 2.0. The designed aplanatic imaging optics exhibited additional aberrations in the multi-layered stack, mainly due to the air-gap and spacer layer. Given optics designed only to compensate for aberrations caused by a 2-μm-thick cover-layer, a 3-μm-thick spacer layer induces 96.2 mλ_rms and 6.5 mλ_rms of spherical aberration and defocus, respectively. A complete electric field calculation analysis for the inside of the multi-layer stack verified that diffraction-limited spot quality can be ensured on the recording layer with phase-only correction. As the aberration caused by the multi-layered stack cannot be corrected perfectly, due to the high oscillation of the aberration function along the radial direction in the exit pupil, three different types of liquid crystal (LC) electrodes were considered for practical implementation. Of the three phase-correction methods, the approximate linear phase-correction method was the most tolerant of axis decenter from the optical axis, providing acceptable diffraction-limited correction performance.     

计算多层膜电场分布的新矩阵方法

引入一种新的薄膜特征矩阵,用以计算多层膜中的电场分布,得到了TE和TM波电场的简单表达式。计算并绘制了薄膜偏振器和感应反射滤光片的内部电场分布曲线。应用新的薄膜特征矩阵,也可以很容易推导出多层膜的表面等离子激光波的色散关系。     

规整膜系层厚允许误差的研究

提出了一种通过计算机模拟薄膜的淀积过程来计算规整膜系层厚允许误差的方法,所计算的层厚允许误差不仅取决于膜系的设计结构,还与薄膜的淀积工艺、镀膜设备的监控精度有关.实验结果表明:采用这种方法所计算出的层厚允许误差对于薄膜的实际镀制具有指导意义.     

Thorium free antireflection coating in MWIR region on Silicon optics

Most infrared transmitting optics have high refractive indices which in turn have high per surface reflection loss. So antireflection coating has very important role in increasing the transmission in the desired wavelength region. In this paper a study has been carried out on the design and fabrication of Thorium free antireflection coating effective for Silicon substrate in MWIR (3.6–4.9 μm) region. The wave band 3.6–4.9 μm is chosen for the reported work because the detected system used in MWIR region has a band selection filter effective in the same wavelength region. Comprehensive search method was used to design the multilayer stack on Silicon substrate. The coating materials used in the design were Germanium (Ge) and Silicon dioxide (SiO₂). The fabrication of coating was made in a coating plant fitted with Cryo pump system and Residual Gas Analyzer. The evaporation was carried out at high vacuum (2–6 × 10–6 mbar) using Electron Beam Gun and layer thicknesses were measured with crystal monitor. The result achieved for the antireflection coating was 96% average transmission in 3.6–4.9 μm band which withstood MIL-F-48616 environmental testing. This work provides an alternate antireflection coating on Silicon by replacing radioactive Thorium Fluoride, used as a coating material in most IR antireflection coating designs.