光回馈Nd:YAG激光器中的多模跳变现象

研究了Nd:YAG激光器中光回馈引起的多模跳变现象.光回馈调制了激光器不同纵模的阈值增益，阈值增益最低的纵模获得振荡.在外腔调谐过程中，当振荡模式的阈值增益高于相邻模式的阈值增益时产生模跳变，光强调制曲线出现相应的波动.各跳变纵模在增益曲线上的位置不同，导致模跳变点位置不同，相应的光强调制曲线也不同.越靠近中心频率的纵模，其光强信号峰值越大，该纵模持续振荡时间也就越长.当两跳变纵模关于中心频率对称时，其光强信号峰值相等，纵模持续振荡时间也相等. 关键词： 自混合干涉 模跳变 光回馈 阈值增益     

基于猫眼腔镜损耗调节的激光横模演示系统

提出一种基于猫眼腔镜损耗调节的新型激光横模演示系统。采用半外腔He-Ne激光器,利用由分立的可进行五维微调的凸透镜和凹面镜组成的猫眼逆向器构成损耗可调激光谐振腔,通过调节猫眼逆向器改变激光谐振腔的损耗比，实现改变激光横模状态的作用。利用CCD进行图像采集，计算机实现图像存储，从而得到20多种结构清晰的高阶横模花样图片。     

Influence of Feedback Levels on Polarized Optical Feedback Characteristics in Zeeman-Birefringence Dual Frequency Lasers

The influence of feedback levels on the intensity and polarization properties of polarized optical feedback in a Zeeman-birefringence dual frequency laser is systematically investigated. By changing the feedback power ratio, different feedback levels are obtained. Three distinct regimes of polarized optical feedback effects are found and defined as regimes Ⅰ, Ⅱ and Ⅲ The feedback level boundaries among the regimes are acquired experimentally. The theoretical analysis is presented to be in good agreement with the experimental results.     

凝视型长波红外折衍混合光学成像系统设计

设计了一套折衍混合凝视红外热成像光学系统.该系统工作波段为8~12 μm, F数为1,全视场达12°, 总长140 mm,两个透镜均采用锗材料。衍射器件制作在第二片透镜的凸面上，可以采用金刚石车削技术进行加工．该系统成像质量接近衍射限并且相对折射系统更好地校正了色差.     

Laser Micro-beam Manipulation System for Cells

This paper introduces a laser micro-beam system for cells manipulation. The laser micro-beam system comprises a laser scissors and a laser tweezers, which are focused by a Nd∶YAG laser and a He-Ne laser through a microscope objective, respectively. Not only the overall design of the laser micro-beam system is discussed, but also the design and choice of the critical components. A laser micro-beam system was constructed and anticipated experiment results were gained. Yeast cells can be successfully manipulated with the laser tweezers. Chromosomes can be successfully incised with the laser scissors.     

溶剂化金属原子浸渍法制备高分散负载型催化剂——Ⅵ.聚合物负载Ni-Cu双金属催化剂的制备及其研究

本文利用金属蒸气法制备了Ni-Cu/D72双金属催化剂。TEM和XRD的测定结果表明该催化剂的分散度很高。金属原子簇颗粒的平均直径为2.1nm。XPS测定结果表明,金属镍主要以Ni(Ⅱ)存在,铜主要以零价态存在,与金属蒸气法制备的Ni-Cu/SiO_2和Ni-Cu/r-Al_2O_3催化剂相比,Ni-Cu/D72催化剂在丙酮和二丙酮醇加氢反应中具有较高的催化活性。     

A Novel Tunable Dual-frequency Laser with Large Frequency Difference

This paper proposed a novel tunable dual frequency laser with large frequency difference,which used LD to pump the Nd∶YAG microchip in the end surface and put the liquid pressure on the radial direction of the crystal by a pressure-transporting thin film. As a result of the stress birefringence, there was a mode splitting phenomenon of the microchip laser longitudinal mode. Both theoretical analysis and experiments indicated that there is a directly proportional relation between the frequency difference and the pressure, so the tunable frequency difference could be obtained when the pressure was changed. A large frequency difference of about 3.4 GHz with linear tunable relation was achieved in the experiment,so it can be a practical light source for the absolute distance interferometry.     

3-烷基/芳基-6-(2', 4'-二氯苯基)-7H-1, 2, 4-三唑[3, 4-b]- 1, 3, 4-噻二 嗪的合成及波谱性质

以间二氯苯与氯乙酰氯反应,生成ω-氯代-2,4-二氯苯乙酮(1),再使之分别与3-烷基/芳基-4-氨基-5-巯基-1,2,4-三唑(2a～2l)反应,合成了12种新的3-烷基/芳基-6-(2',4'-二氯苯基)-7H-1,2,4-三唑并[3,4-b]1,3,4-噻二嗪(4a～4l)。利用EA,IR,^1HNMR确定了其结构,并提出该反应的可能机制。     

色散缓变光纤中飞秒光脉冲的调制不稳定性研究

研究了色散缓变光纤中飞秒光脉冲的调制不稳定性 ,发现当色散缓变光纤的色散参量满足一定关系式时 ,增益谱的谱宽最宽 ,获得了增益谱的表达式 ;三阶色散对调制不稳定性不起作用 ;自变陡效应使增益谱的谱宽变窄 ,振幅的增长速度减漫 ;拉曼效应改变了调制不稳定性的产生区域。     

差分系统的渐近稳定性定理及渐近稳定性区域

本文首先给出了一个利用构造Liapunov函数来判别差分系统渐近稳定性的定理,此定理改进了已有结论[1]且在应用上更为方便.然后,给出了对于自治差分系统,求其渐近稳定区域或吸引区域的几个定理.