溶胶-凝胶双层三波长增透膜制备

通过理论模拟与实验相结合,研究了以双层膜的方式实现三波长增透的途径。以正硅酸乙酯为前驱体,采用酸催化与碱催化溶胶混合的方式调控了溶胶折射率,并配制了双层复合膜所用的两种溶胶,制备出了351nm处透过率大于99.5%,527nm透过率大于98%,1053nm透过率大于98%的三波长增透膜。用扫描电镜、原子力显微镜观测了膜层结构,用椭偏仪和分光光度计对膜层性能进行了表征。三波长增透膜对高功率激光装置的运行性能提升起到了积极的促进作用。     

溶胶-凝胶双层三波长增透膜制备

通过理论模拟与实验相结合,研究了以双层膜的方式实现三波长增透的途径。以正硅酸乙酯为前驱体,采用酸催化与碱催化溶胶混合的方式调控了溶胶折射率,并配制了双层复合膜所用的两种溶胶,制备出了351 nm处透过率大于99.5%,527 nm透过率大于98%,1053 nm透过率大于98%的三波长增透膜。用扫描电镜、原子力显微镜观测了膜层结构,用椭偏仪和分光光度计对膜层性能进行了表征。三波长增透膜对高功率激光装置的运行性能提升起到了积极的促进作用。     

基于液体光学补偿自动定向基准的研究

 用理想倍率元件进行匹配,对4种液体光学补偿通用构架模型分析推导,得出如单液面、双液面、液体中的反射及透射等诸多平行光路中补偿光学结构的数学模型。设计和演变的光学结构是在液体中置反射镜,光线两次通过液体自然表面,再与理想倍率的平板或施密特棱镜匹配所构成的,水平定向和坡度定角精度能够达到0.01″。给出液体补偿方式匹配表对文中未举例的其他液体光学补偿结构的构成和演变方式具有指导意义。最后对设计的结构补偿误差进行分析和实验验证,给出水平补偿曲线、横摆补偿曲线和像旋补偿曲线。     

数字全息显微像平面相位畸变的自动补偿研究

对离轴数字全息显微相位畸变的自动补偿进行了理论和实验研究。首先对由CCD记录的数字全息图采用平均梯度自聚焦方法确定最佳再现距离,然后将修正的虚拟参考光作用于切趾滤波后的全息图进行数字再现,经像平面相位自动补偿后得到无畸变的物体相位分布。该方法仅需记录一幅离轴数字全息图就可以自动快速地重建物体的真实相位信息。     

Measurements of cirrus clouds with a three-wavelength lidar

A three-wavelength lidar system is set up. The backscatter signals of 355, 532, and 1 064 nm are mea- sured simultaneously to derive the optical depth, lidar ratio, and backscatter color ratio of cirrus clouds, respectively. The lidar configuration and the data processing are described. The case study shows that the optical depths of cirrus clouds are not dependent on wavelength while the backscatter color ratios are.     

Automatic compensation of laser beam focusing parameters for flying optics

Flying optics technologies are used for a range of applications such as a large workpiece processing and laser texturing. It is essential to compensate the variations of laser beam focus parameters while the focus head is moving. A flying optics automatic compensation approach is proposed to achieve invariable laser focal size, focus depth and focus position through computer controlled objective lens and focus lens position. A simple mechanical control method is also presented for the realization of constant beam parameters for flying optics. Numerical simulation is illustrated for a CO₂ laser texturing application. The flying optics parameters compensation is simple and easy to control.     

Influence of binder viscosity on the control of infrared emissivity in low emissivity coating

Low emissivity is the complex system and polymer binder is one of the most important factors that affect optical and mechanical properties of the coating. Low infrared emissivity coatings were prepared by using flake aluminum particles and three types of polymer resins as fillers and binders, respectively. The influence of polymer binder viscosity on pigment particles distribution, surface morphology and infrared emissivity of the coating was systematically investigated. The results indicate that infrared emissivity of the coating can be strongly affected by the resin viscosity at the same preparation condition, which induces different aluminum particles distribution and surface morphology of the coating. Low resin viscosity is helpful for aggregating pigments and reducing the top polymer layer thickness near the surface, thus the infrared emissivity is reduced. If the resin viscosity value is decreased by two orders of magnitude, the infrared emissivity values would be reduced as much as 0.2. Additionally, a theoretical model is proposed to account for this mechanism, which indicates that sedimentation, evaporation and diffusion play important roles in forming different aluminum particles distribution during the drying process of the coating.     

全介质三波长消偏振平板型分光膜的设计

 利用Needle合成法与Conjugate graduate精炼法,并基于Thelen和Costich的理论选择初始膜系的材料和结构,设计了532,633和1 315 nm三波长消偏振平板型分光膜。结果表明,此膜系在(532±10), (633±10)和(1 315±10) nm范围内的偏振分离都非常小。对于532,633和1 315 nm 3个波长位置的消偏振要求,入射角的合理变化范围可以是45±2°。     

PSO-ASVR在三波长路面状态传感器定量标定中的应用

路面状态传感器是路面状态定性识别和定量测量的重要工具,其定量测量性能依赖于定量标定模型的准确性。为了解决路面状态传感器定量标定数据非线性和非均匀分布问题对定量测量的不利影响,提出基于PSO-ASVR(particle swarm optimization-adaptive support vector regression)的路面状态传感器定量标定模型。构建AP(adaptive preprocessing)流程进行标定数据最优化预处理,降低路面状态传感器非均匀分布问题影响下的标定数据处理误差。采用基于结构风险最小化的SVR(support vector regression)算法进行标定数据拟合,并利用PSO(particle swarm optimization)算法实现SVR中参数最优化,降低路面状态传感器标定数据非线性引入的数据拟合误差。不同路面状态条件下标定数据处理实验表明:新方法相比于传统方法在均方根误差RMSE上至少可减小63%,验证了其在提高定量标定模型精度上的有效性,实现了路面状态传感器定量标定误差的降低。     

全介质三波长消偏振平板型分光膜的设计

利用Needle合成法与Conjugate graduate精炼法,并基于Thelen和Costich的理论选择初始膜系的材料和结构,设计了532,633和1 315 nm三波长消偏振平板型分光膜。结果表明,此膜系在(532±10), (633±10)和(1 315±10) nm范围内的偏振分离都非常小。对于532,633和1 315 nm 3个波长位置的消偏振要求,入射角的合理变化范围可以是45±2°。     

无透镜傅里叶变换数字全息术中非共面误差的自动补偿算法

无透镜傅里叶变换数字全息术对活细胞进行显微相衬成像测量时,由于细胞处于运动状态导致记录物体与参考点源难以共面,从而引入成像误差.本文提出了一种有效可靠的基于位相分布的自动对焦再现算法,只需通过一幅全息图,即可确定出记录距离的优化数值解,并结合一次位相线性拟合,成功补偿掉非共面误差.将这种算法应用到活体宫颈癌细胞的相衬成像实验中获得了较为理想的实验结果,表明了这种自动补偿非共面误差算法的可行性. 关键词： 数字全息 无透镜傅里叶变换全息 自动对焦 位相畸变校正     

Automatic polarization compensation method for low-repetition frequency short optical pulse

An automatic polarization compensation method for low-repetition frequency short optical pulse is proposed and successfully applied to the master oscillator room (MOR) in inertial confinement fusion (ICF) systems to maintain the MOR maximum output energy. After an average of 37 shots, the MOR output energy reaches maximum value with the sudden occurrence of polarization variation in the fibers. The peak-to-peak amplitude jitter of the MOR output is 9.52% at 4 h, which meets the requirement of the ICF system.     

Automatic compensation of magnetic field for a rubidium space cold atom clock

When the cold atom clock operates in microgravity around the near-earth orbit, its performance will be affected by the fluctuation of magnetic field. A strategy is proposed to suppress the fluctuation of magnetic field by additional coils, whose current is changed accordingly to compensate the magnetic fluctuation by the linear and incremental compensation. The flight model of the cold atom clock is tested in a simulated orbital magnetic environment and the magnetic field fluctuation in the Ramsey cavity is reduced from 17 nT to 2 nT, which implied the uncertainty due to the second order Zeeman shift is reduced to be less than 2×10~(-16). In addition, utilizing the compensation, the magnetic field in the trapping zone can be suppressed from 7.5 μT to less than 0.3 μT to meet the magnetic field requirement of polarization gradients cooling of atoms.     

High-temperature spectral emissivity of SiC in the IR range

A three-layer optical model is proposed for the IR radiator based on SiC with the help of which the SiC emissivity is calculated at a temperature 1650 K and the bands in the 9–25-μm region are interpreted.     

Apparent directional spectral emissivity determination of semitransparent materials

An inverse estimation method and corresponding measurement system are developed to measure the apparent spectral directional emissivities of semitransparent materials. The normal spectral emissivity and transmissivity serve as input for the inverse analysis. Consequently, the refractive index and absorption coefficient of the semitransparent material could be retrieved by using the pseudo source adding method as the forward method and the stochastic particle swarm optimization algorithm as the inverse method. Finally, the arbitrary apparent spectral directional emissivity of semitransparent material is estimated by using the pseudo source adding method given the retrieval refractive index and absorption coefficient. The present system has the advantage of a simple experimental structure, high accuracy, and excellent capability to measure the emissivity in an arbitrary direction. Furthermore, the apparent spectral directional emissivity of sapphire at 773 K is measured by using this system in a spectral range of 3 μm–12 μm and a viewing range of 0?–90?. The present method paves the way for a new directional spectral emissivity measurement strategy.     

Neutrino emissivity of quark matter at finite temperatures

We evaluate the emissivity rates for d-decay and s-decay by exactly solving the angular integrals involved and without assuming the degeneracy of electrons. We have also studied the effects of QCD coupling constant as well as the s-quark mass on the emissivity rates. We find that these parameters are important in determining the threshold and extinction densities for d- and s-decays.