激光涂层在多冲碰撞载荷下的变形与失效研究

In applying impact loads with multishocks to perform shock experiments for laser cladded cobalt-base and nickel-base alloy coats on the surface of mild carbon steel or austenitic stainless steel, it is found that, under an impact force that is 11%-43% of the static yield limit of the material, micro-plastic deformation is generated both in the coat and upper part of the base. Repeated trials will cause cumulated macro-plastic deformation. After a total of 250,000 impacts, relative deformation rates of 2.2% and 8.9% result in the coat and base, respectively. Moreover, there is a rigidification phenomenon both in the coat and upper part of the base. When the coat covers the entire base, under impact loads with multishocks, the final stress is less than that when the base is only partly covered, and the life is longer.There is intense deformative rigidification and material floating effect on the lower part of the edge of the covering coat. Meanwhile, cracks are likely to occur and spread in this part.     

透明介质光学击穿的理论与数值计算

以石英玻璃为例,计算了导带电子光吸收速率、雪崩击穿速率和光致电离速率,发展了雪崩击穿模型,建立了激光-石英玻璃相互作用的动态理论,并用fortran语言编程求解了耦合方程组.研究表明,在400nm激光作用下,当样品表面形成等离子体时,激光局域在样品表面而不是迅速下降.我们以能量沉积为标准计算了材料破坏阈值与脉冲宽度的依赖关系,理论结果与实验符合得很好.结果表明,即使在可见光的飞秒激光作用下,碰撞电离仍是导带电子产生的主要机制.     

对量子噪声实虚部互关联情况下饱和激光模型光强涨落的分析

针对实、虚部关联的量子噪声及泵噪声驱动的饱和激光模型,基于近似福克—普郎克方程,推导激光强度定态概率分布函数,利用投影算子法,分析了由于量子噪声实虚部关联度λq导致锁相时的光强度关联函数C(τ)和集中驰豫时间Tc。通过计算机数据计算及作图,得到了定态情况下光强概率分布函数图形,讨论了量子噪声实、虚部的互关联对光强关联函数和集中驰豫时间的影响。结果表明:量子噪声实、虚部互关联会导致激光强度涨落增大。     

Er^3＋-Yb^3＋ Co-Doped Fiber Ring and Line Laser

Er^3 -Yb^3 co-doped fiber of 2 m long is used as the laser gain medium. Two fiber lasers with different structures have been set up, one is the line cavity fiber laser with the dielectric mirror being replaced by an all-fiber reflecting mirror,the other is the ring cavity all-fiber laser. Both set-ups have achieved lasing operation at the wavelength of 1.53 μm. Pumped by the 1 064 nm light from all-solid-state Nd : YAG laser, the two fiber lasers at 1 530 nm are operational. Their output powers are 7.8 mW and 2 mW with 130 mW and 160 mW pump powers.     

三维彩色扫描系统及算法

提出了一种大尺寸 3D物体几何形状的扫描测量系统 ,该系统由一个线结构光源和一个彩色CCD摄像机组成 .CCD摄像机两次摄取被扫描物体的图像 ,首先从激光平面中获取被扫描物体的三维信息 ,然后将 3D物体的彩色信息和三维信息自动进行叠合 ,以获得 3D物体的真实模型 .     

激光的振幅和位相调制诱导分子的局域模振动

在两激光场与三能级分子相互作用系统中，调制光场的振幅和位相，诱导分子的局域模振动，并讨论了分子的动力学规律     

MPEG压缩技术与VCD2.0光盘制作系统在教学上的应用

MPEG是有关图像数据和声音数据的压缩编码技术 ,用该技术发展起来的VCD播放器已大量进入家庭、学校和单位 ,如何将这一先进的设备更好地发挥在教学活动中 ,是摆在我们面前的一项重要任务。本文通过对MPEG压缩技术和VCD2 0光盘制作系统的介绍 ,使读者对VCD2 0在教学活动中使用的情况有一个较深的了解     

Sagnac效应与激光陀螺

依据相干光学理论,从Sagnac效应出发,分析讨论了激光陀螺的基本原理,并简要的介绍了二频单激光陀螺和四频差动激光陀螺的工程化过程及应用前景.     

基于通讯车图像传输系统--一种基于通讯车的卫星中继遥控机的红外激光全息图像传输系统

基于通讯车的卫星中继遥控机的红外激光图像传输系统在遥感图像的传输中有着极其重要的军事和民用价值。首先讨论系统的应用意义，然后提出系统的总体方案，并对几个关键电路进行设计，最后分析其可行性。     

Raman crystal lasers in the visible and near-infrared

Raman lasers based on potassium gadolinium tungstate and lead tungstate crystals pumped bya≈120 ps Nd: YAG laser at 1.064 μm were developed. High reflection mirrors for the Stokes wavelength have been used to generate near-infrared and eye safe spectral region of 1.15–1.32 μm. Second harmonic generation of the generated Raman lasers was observed. Eifficient multiple Stokes and anti-Stokes picosecond generation in 64 crystals have been shown to exhibit stimulated Raman scattering on about 700 lines covering the whole visible and near-infrared spectrum. All stimulated Raman scattering (SRS) wavelengths in the visible and near-infrared spectrum are identified and attributed to the SRS-active vibration modes of these crystals.