波长1O64nm脉冲激光高阈值反射膜的研制

研究 Ｈｆ Ｏ２／ Ｓｉ Ｏ２ 高反射膜的制备工艺及其激光诱导损伤阈值的比较测试,分别采用了反应蒸镀 Ｈｆ Ｏ２、反应离子辅助蒸镀 Ｈｆ Ｏ２、反应离子辅助蒸镀金属 Ｈｆ 的源材料形成 Ｈｆ Ｏ２ 薄膜。采用这三种工艺制备了 Ｈｆ Ｏ２ ／ Ｓｉ Ｏ２ 高反射膜,在中心波长 １０６４ｎｍ 处,反射率 Ｒ≥９９．５％ ,其中反应蒸镀 Ｈｆ Ｏ２ ／ Ｓｉ Ｏ２ 高反射膜损伤阈值最高,可达 ６０ Ｊ／ｃｍ ２（１０６４ｎｍ ,５ｎｓ）。     

超高阈值Pick-off反射镜的研制

 采用水中抛光技术抛制了90mm×60mm×10 mm的K₉玻璃基片,表面粗糙度达1nm。在APS1504镀膜机上,摸索了电子束蒸发镀膜的最佳工艺条件,较稳定地在该超光滑玻璃表面上镀制了对波长1054 nm、入射角45°、反射率R≥99.5%的反射膜。膜层的抗激光损伤阈值可达26 J/cm²(1054nm, 1ns),镀膜后该玻璃基片反射波前可达l /10(p-v),最终制备了超高阈值Pick-off反射镜。     

Tm3+在亚碲酸盐玻璃中升频发光的研究及其光谱性质的J-O计算

报道了一种新组份亚碲酸盐玻璃作为掺稀土基质在提高升频发光效率方面的优良特性.在970mmLD泵浦下这种Tm³⁺掺杂的亚碲酸玻璃明显的蓝色及红色升频发光,通过测量其吸收光谱,用J-O理论计算了这种玻璃基质中Tm³⁺离子各发光能级的自发辐射几率、跃迁振子强度、分支比及寿命等光谱参量.并计算了481mm和650mm两种发光的发射截面.     

LD泵浦Nd∶YAG/Cr∶YAG腔外频率变换高功率紫外激光器

用KTP晶体对激光二极管端面泵浦的Nd∶YAG晶体,Cr∶YAG被动调Q产生的1064 nm脉冲激光器进行腔外倍频,用BBO晶体四倍频产生266 nm紫外激光.用15 W的LD阵列,当LD泵浦功率为12 W的情况下,红外(1064μm)调Q平均输出功率为2.2 W,脉冲序列周期为40μs,脉宽为18 ns,峰值功率高达4.9 kW.采用KTP腔外二倍频,532 nm的绿光输出平均功率为850 mW;用BBO腔外四倍频,266 nm的紫外光输出平均功率高达215 mW,绿光-紫外光光转换效率为25.2%,红外到紫外总的转换效率为9.8%.     

基于坐标变换的动态光学成象性质研究

本文利用齐次线性坐标变换,将光学系统的高斯物象共轭理论用齐次坐标变换的方法来描述,并与动态光学理论中的作用矩阵相比较,阐述了坐标变换方法与动态光学理论的关系;推导了一些重要的动态光学系统的成象性质,验证了动态光学的一系列结论.通过本文的研究,证明了坐标变换方法与动态光学理论的一致性,也明确了在动态光学系统内坐标变换方法的应用方法.     

1.315μm光解碘激光的大气透过率测量实验

利用1.315μm光解碘激光器在实际大气中作了大气透过率的测量,在中等能见度,相对湿度为64％和温度为21℃的条件下,平均透过率为0.78,同时用现有的数据库和计算程序作了计算比较,发现实验结果与计算值基本一致。     

Convenient method for calibrating system constant of scanning water vapor Raman lidar

<正>Lower tropospheric water vapor measurements are performed at nighttime using the mobile atmosphere monitoring lidar-2(AML-2) which is operated by the Anhui Institute of Optics and Fine Mechanics.In this lidar system,a 354.7-nm light from a Nd:YAG laser is used as stimulating source,whose Raman shifted center wavelengths are at 386.7 and 407.5 nm for nitrogen and water vapor,respectively.We present a novel and convenient method for determining the Raman lidar calibration constant according to the scanning performance of this lidar.We are likewise able to realize the measurement of water vapor profile in the low troposphere.The error induced by the uncertainty of calibrated constants is within 7% for the Raman lidar system.Experimental results from two months of study indicate that the method of calibrating the lidar system constant is feasible,and the Raman lidar performance is stable and reliable.     

Nickel‐Catalyzed Activation of Acyl C−O Bonds of Methyl Esters

We report the first catalytic method for activating the acyl C?O bonds of methyl esters through an oxidative‐addition process. The oxidative‐addition adducts, formed using nickel catalysis, undergo in situ trapping to provide anilide products. DFT calculations are used to support the proposed reaction mechanism, to understand why decarbonylation does not occur competitively, and to elucidate the beneficial role of the substrate structure and the Al(OtBu)₃ additive on the kinetics and thermodynamics of the reaction.     

An oxidized squalene derivative from Protium subserratum Engl. (Engl.) growing in Peru

Protium subserratum (Burseraceae) is a neotropical tree species that is comprised of several habitat-specific ecotypes having distinct defense chemical profiles. A previously unknown triterpene, 25,30-dicarboxy-26,27,28,29-tetraacetoxy-10,11,14,15-tetrahydrosqualene, was isolated from P. subserratum young leaf tissue of one ecotype growing in Peru. The structure of 1 was determined by spectroscopic study, including 1 and 2D nuclear magnetic resonance experiments.     

Largest lyapunov exponents for lattices of interacting classical spins

We investigate how generic the onset of chaos in interacting many-body classical systems is in the context of lattices of classical spins with nearest-neighbor anisotropic couplings. Seven large lattices in different spatial dimensions were considered. For each lattice, more than 2000 largest Lyapunov exponents for randomly sampled Hamiltonians were numerically computed. Our results strongly suggest the absence of integrable nearest-neighbor Hamiltonians for the infinite lattices except for the trivial Ising case. In the vicinity of the Ising case, the largest Lyapunov exponents exhibit a power-law growth, while further away they become rather weakly sensitive to the Hamiltonian anisotropy. We also provide an analytical derivation of these results.