Linearly polarized operation of Yb-doped fiber laser by Brewster's angle-polished fiber end

<正>A new method to obtain linear polarization operation by Brewster's angle-polished fiber end is demonstrated. By using the special polarization operation technique together with introducing a narrow-linewidth fiber grating into the laser cavity,a cladding-pumped linear polarization and single-transverse-mode (M~21.1) Yb-doped fiber laser with narrow linewidth whose full-width at half-maximm(FWHM) is less than 0.2 nm,is obtained in a simple configuration.The output power is up to 10 W which is continuouswave output at 1085 nm,and the slope efficiency is 63%with respect to the coupled pump power and 75%with respect to the absorbed pump power,respectively.The measured 21-dB polarization extinction ratio does not degrade with the output power.The simplicity of such an approach is highly beneficial for a number of applications,including the use of a fiber laser for the nonlinear wavelength conversion (especially for the intracavity frequency doubling) and for the coherent and spectral beam combination.     

Ni－海泡石催化剂的热稳定性和抗毒性

Ｎｉ－海泡石催化剂的热稳定性和抗毒性曹声春，杨礼嫦，彭峰，周军，郭栋材（湖南大学化工系，长沙４１００８２）关键词镍，海泡石，负载型催化剂，耐热性，抗毒性，苯，环己烷国内外现行的苯加氢过程主要采用Ｎｉ－ＡＩ。Ｏ。催化剂．但它存在耐热性差、易中毒、活性温...     

国产掺镱双包层光纤的激光特性

 采用MCVD方法研发了掺镱双包层光纤，并对其结构特性、荧光特性和激光特性进行了测试和研究。其D形内包层尺寸为400/450μm，数值孔径为0.36,纤芯直径约为16μm，数值孔径约为0.18。荧光谱线的范围为1 000~1 140 nm，1 030 nm处的峰宽大于50 nm。采用大功率激光二极管单端泵浦6 m长的双包层光纤，在泵浦入纤功率为61 W时， 获得了32 W的激光输出，斜率效率为64%。该光纤在高功率处未发现饱和现象，通过优化光纤参数与泵浦方式还可以提高转化效率和输出功率。实验表明该光纤可以取代进口光纤用作高功率激光器件。     

电磁AB效应与描述电磁场的基本物理量

本文通过介绍电磁ＡＢ效应及其实验验证，论证了描述电磁场的基本物理量应为规范条件约束下的电磁势（φ，Ａ），而不是场量（Ｅ，Ｂ）．     

Yb:Y2O3透明陶瓷的光学性能研究

介绍了一种基于纳米粉末真空烧结技术的新型固体激光材料——Yb：Y₂O₃多晶陶瓷的制备工艺、物理化学特性、能级结构和光谱特性，并与Yb：YAG单晶进行了对比.采用紧凑型有源镜激光器(CAMIL)的抽运方式，验证了Yb：Y₂O₃透明陶瓷的激光输出性能.在35W的最大抽运功率下，得到波长1078 nm，功率10.5 W 的连续激光输出，斜率效率达到37.5%.实验中还观察到激光输出波长随抽运功率增加而红移以及随输出耦合镜变化而漂移的现象.Yb：Y₂O₃多晶陶瓷是一种理想的激光材料，不仅具有与Yb：YAG单晶同样优秀的物理化学性能和光谱特性，而且其热导率和发射带宽约为Yb：YAG单晶的两倍，非常适合于高亮度激光器和超短脉冲激光器领域的发展应用. 关键词： 2O₃陶瓷')" href="#">Yb:Y₂O₃陶瓷 陶瓷激光器 透明陶瓷     

An acousto-optic Q-switched fiber laser using China-made double-cladding fiber

A simple laser-diode pumped acoustic-optic Q-switched fiber laser is reported by using China-made large- mode-area ytterbium-doped fiber.Q-switched pulses with a beam quality factor of M~2≈2 and several hundred nanoseconds pulse duration are achieved at the repetition rate of 1-50 kHz.When the repetition rate is 1 kHz,the pulse energy is 0.93 mJ with the pulse duration of 132 ns.Meanwhile,the profile of laser pulses shows some mode-locking phenomena,the mechanism of the phenomena is discussed.     

低能电子入射电离He原子二重微分截面的理论研究

研究了低能电子入射单电离He原子的二重微分截面(DDCS)，通过对散射电子三重微分截面在全空间的角度积分得到敲出电子的DDCS.分别用DS3C模型和BBK模型计算了入射能为26.3，28.3，30.3，32.5，34.3，36.5和40.7eV时，低能电子入射电离He原子的DDCS；研究表明：DS3C的计算结果，除在低入射能(比如26.3eV)和小敲出角之外，均能与绝对测量的实验结果较好地符合.此外，对直接和交换效应也进行了研究，给出了交换效应对截面的贡献.     

机载激光雷达沙尘探测能量优化配置的统计研究

依据美国ANSI标准,结合1999~2004年间地基激光雷达探测的合肥地区沙尘暴消光廓线,统计分析了机载大气探测激光雷达探测沙尘时偏振532 nm垂直通道和1064 nm通道所需的最小激光能量,模拟计算了机载大气探测激光雷达探测沙尘暴时在0~12km高度范围内不同激光束发散角和激光脉冲能量比例的532 nm和1064 nm激光脉冲眼睛安全最大阈值能量。以合肥地区沙尘暴消光特性的统计结果、地面人眼安全标准和两个"瓶颈"通道的探测能力为依据提出两种激光脉冲能量配置方案。     

A new differential absorption lidar for NO_2 measurements using Raman-shifted technique

Based on Raman-shifted wavelengths of D2 and CH4 pumped by third harmonic of Nd:YAG laser, a differential absorption lidar was presented in this paper and had been constructed for probing environmental NO2 concentration. NO2 experimental measurements were carried out at Anhui Institute of Optics and Fine Mechanics in Hefei. Some NO2 measurement results were given and discussed.     

光栅摄谱仪的改进及其在周期性极化的铌酸锂晶体倍频研究中的应用

由于电荷耦合器件(CCD)具有光谱响应范围宽、检出限低、动态范围宽、暗电流和读出噪声低以及具有积分信号、多道同时检测和实时检测等能力的优点,在光谱测量和光谱成象领域获得了广泛的应用。将传统的1m光栅摄谱仪和科学CCD相结合,使其具有实时快速测量激光光谱的能力。将其应用于宽带双包层光纤激光在周期性极化的LiNbO₃晶体(PPLN)中倍频特性的研究,观察到了倍频激光光谱随PPLN控制温度的动态变化过程,并对此进行了详细分析。