Automated damage diagnostic system for laser damage threshold tests

<正>An automated damage diagnostic system for collecting plasma flash is developed to diagnose damage in a laser-induced damage threshold(LIDT) test system.Experiment is done to verify the accuracy of this system and analyze the relationship between the plasma signals and the damage morphologies.The results obtained by the system are found to be in excellent agreement with those obtained by the much laborious method of Normaski microscope.Results show that plasma signals above 1 V correspond to the damage morphology of surface discolorations with or without pits in their centers,and plasma signals below or just around 1 V correspond to the damage morphology of pits.The misdiagnosis is attributed to contaminations and air breakdown.     

不同波长激光同时辐照薄膜热效应研究

通过分析两个不同波长激光同时辐照下薄膜体内驻波场分布并求解热传导方程,得到1 064 nm激光和355 nm激光在三倍频分离膜内共同作用下二维温度场分布.研究表明:1 064 nm激光和355 nm激光共同作用引起薄膜体内的温升峰值高于相同能量1 064 nm激光单独作用引起的薄膜体内的温升峰值,低于相同能量355 nm激光单独作用引起的薄膜体内的温升峰值.     

Imaging photothermal microscopy for absorption measurements of optical coatings

For absorption measurement of large-aperture optical coatings, a novel method of imaging photothermal microscopy based on image lock-in technique is presented. Detailed theoretical analysis and numerical calculation are made based on the image photothermal technique. The feasibility of this imaging method is proved through the coincidence between the theoretical results of single spot method and multi-channel method. The measuring speed of this imaging method can be increased hundreds of times compared with that of the raster scanning. This technique can expand the applications of photothermal technique.     

利用周期型正交二元相位板产生正方阵列涡旋和螺旋光场

设计了一种周期型正交二元相位板,其具有周期型矩形调制单元,各单元的相位调制量为0或π。该相位板的空间频谱具有中心直流分量为0的特点,分别对该频谱中心区域的4个一级频谱点和8个二级频谱点进行相位调制,可得到正方阵列光斑和正方阵列涡旋。阵列涡旋中各涡旋光束的拓扑荷数l=±1,在空间交错分布。由于两个正方阵列光场在垂直传播方向的横向周期恰好重合,且两个光场沿光轴方向的波数不同,因此叠加之后可以形成强度分布随传输距离旋转的正方阵列螺旋,阵列中存在两种具有相反螺旋方向的螺旋光束,同样在空间呈交错分布。此外,讨论了产生最佳螺旋光束的相位板设计条件,并给出理想情况下系统的能量利用率,所得实验结果验证了该方法的可行性。     

Characteristics of 355 nm Laser Damage in KDP and DKDP Crystals

We present the characteristics of bulk damage induced by the third harmonic of Nd：YAG laser irradiation in KDP and DKDP crystals. Bulk damage occurs as a few or a series of pinpoints consisting of a core and the deforming zone. The results of a 1-on-1 test reveal that the pinpoint size increases with incvreasing fluence, and the pinpoint density increases exponentially with increasing fluence. The results of an s-on-1 test indicate that the pinpoint density increases gradually with laser pulse number, but the size does not grow. These results are consistent with a model in which nanoabsorbers are assumed to exist in the crystal and the initiation of damage is determined by heating them to the critical temperature.     

2,6-二（对氨基苯）苯并[1,2-d;5,4-d']二噁唑的合成和纯化

1,2,3-三氯苯经过硝化、水解、催化加氢、缩合等四步反应，合成了2,6-二（ 对氨基苯）苯并[1,2-d;5,4-d']二噁唑，总产率为70%。同时，研究了一种有效的? 亟峋?,6-二（对氨基苯）苯并[1,2-d;5,4-d']二噁唑的方法。与其他方法相比， 该法原料便宜易得，产物可作为聚合反应的单体原料。     

Damage characteristics of HfO_2/SiO_2 high reflector at 45° incidence in 1-on-1 and N-on-1 tests

P-polarization high reflectors are deposited by e-beam from hafnia and silica. 1-on-1 and N-on-1 tests at 1064-nm wavelength with P-polarization at 45° incidence are carried out on these samples. Microscope and scanning electron microscope are applied to investigate the damage morphologies in both 1-on-1 and N-on~l tests. It is found that the laser damage threshold is higher in N-on-1 tests and nodular defect is the main inducement that leads to the damage because nodular ejection with plasma scalding is the typical damage morphology. Similar damage morphology observed in the two tests indicates that the higher laser damage threshold in N-on-1 test is attributed to the mechanical stabilization process of nodular defects, owing to the gradually increased laser fluence radiation. Based on the typical morphology study, some process optimizations are given.     

一株产α-L-鼠李糖苷酶菌株的分析与鉴定

筛选得到了一株能够分泌α-L-鼠李糖苷酶的菌株。利用TLC和HPLC的方法,对芦丁的生物转化情况进行研究。结果表明,该菌株可以将芦丁降解形成槲皮素。测序结果表明该菌种具有α-L-鼠李糖苷酶基因。根据菌落形态学观察和分子生物学的18SrDNA基因序列分析及系统进化树分析,将该菌株初步鉴定为黑曲霉。更多还原