柱面透镜准直LD光场的计算建模方法研究

为了简化LD光场准直柱面透镜繁琐的理论设计过程,便于进行实际操作,利用Matlab计算建模的方法,计算理想准直柱面透镜上的各个离散点的坐标值,通过拟合或二次曲面方程逼近的方法来获得准直柱面透镜的面型参数。分析表明,二次曲面柱面透镜非常适合做半导体激光器的准直透镜,可以根据具体需要来选择相应的面型。相比于其他方法,该方法简单直观,易于设计和加工,参数的优化调整迅速,可以根据加工工艺的难易程度来选择合理的透镜参数。     

激光扫描声学显微镜光学系统的设计

半导体激光器具有半导体和固体器件的许多优点：结构紧凑、效率高、价格便宜、长寿命，在许多方面优于气体激光器，因此在一些测量领域有较好的应用前景。本文基于棱镜对光的一维压缩及新型半导体激光器，对激光扫描声学显微镜的光学系统进行了新的设计，给出了相关数据及具体技术指标，实验证实其光学性能满足要求。整个光学系统具有结构紧凑、可靠性高、使用方便等特点，现已用于激光扫描声学显微镜定型设计。     

激光二极管抽运固体激光器场分布的热不稳定性研究

通过建立激光介质非热平衡状态的振荡散热模型，分析了激光二极管抽运固体激光器中，热透镜的不稳定性.研究表明，热透镜的这种热不稳定性是造成激光场不稳定的重要因素.会造成高斯半径的不稳定波动，会使激光光束的指向角波动，会造成激光光斑的非对称畸变，这种畸变也处于波动之中.通过对端面抽运条件下，热耗为1W的Nd:YAG激光介质的理论和实验研究，确定了这种原因下光场不稳定度的数量级. 关键词： 激光二极管 固体激光器 热透镜     

A mode-locked dye laser pumped by a xenon ion laser

Passive mode-locking of a rhodamine 6G dye laser has been achieved, using a pulsed xenon ion laser as a pumping source. A pulse width of 5 ps and a peak power of 4 kW have been obtained. Thermal problems were encountered, which adversely affected the operation of the dye laser. Work is in progress to improve these results.     

1.6 W of TEM00 cw output at 1.06 μm from Nd:CNGG laser end-pumped by a fiber-coupled diode laser array

In this paper we demonstrated and analyzed a high-power cw Nd:CNGG laser end-pumped by a fiber-coupled diode laser array in a convex–concave-type cavity. TEM₀₀ mode output power of 1.63 W was obtained with 27% optical-to-optical conversion efficiency and slope efficiency of 44.5%. Thermal lensing and its variation with the incident pump power for this crystal have been measured. The coefficient for pump power induced diffraction losses of Nd:CNGG crystal have also been estimated for this laser configuration.     

一种新颖的激光准直系统的研究

本文用等效望远镜系统的方法研究了锥形梯度折射率纤维透镜用作激光准直系统的原理和特性,指出这种新颖的激光准直元件可望在微型光学和波导光学中获得新应用。     

半导体泵浦铷蒸气激光器出光实验

针对中心波长780 nm的商用连续波半导体激光器,使用斩波器将连续激光变为脉冲输出形式,用2400 line/mm的平面全息光栅搭建Littrow外腔将线宽压窄至0.2 nm以下。采用透镜组对线宽压窄后的半导体激光进行光束整形,半导体激光经线宽压窄和光束整形后,经透镜聚焦进长约8 mm的铷蒸气泡进行半导体泵浦碱金属激光实验。首次出光得到17.5 mW的基模线偏振铷激光;在最新的改进实验中,半导体泵浦铷激光输出功率已达到2.8 W。     

大面阵激光二极管阵列端面泵浦耦合技术

为了满足常温Yb:YAG激光放大器对泵浦功率密度的要求,设计了一种高缩束比的耦合系统。根据激光二极管（LD）的发光特性,将输出功率为80 kW的LD阵列进行拟球面排列,采用正交柱面透镜配合空心导光管进行泵浦耦合,耦合系统的面积缩束比高达86∶1。模拟计算表明,该耦合系统的耦合效率对导光管反射板的反射率依赖性较低,且脱离耦合系统后的泵浦光传输8.5 mm后,依然可以保持泵浦光场的轮廓,满足端面泵浦的常温Yb:YAG片状放大器对泵浦耦合系统的要求。     

高功率叠阵二极管激光器光束整形

采用光线追迹法详细分析线阵二极管激光器经微球面柱透镜快轴准直后的光强变化情况,利用快轴准直微球面柱透镜的球差可调整输出激光光强分布的特性,得出了快轴准直输出发散角约5时光强分布具有较好的平顶形式。根据叠阵二极管激光器输出光的特点,设计了由25个二极管激光器组成的叠阵二极管激光器的光束整形输出系统,该系统由快轴准直微透镜、快轴耦合透镜和慢轴耦合透镜组成,把需要泵浦的激光介质薄片设计在快轴耦合透镜的焦点上,并且在慢轴耦合透镜的成像面附近,得到了7 mm8 mm的泵浦光斑,光强不均匀性约10%,输出效率达到85%。     

大面阵激光二极管阵列端面泵浦耦合技术

为了满足常温Yb:YAG激光放大器对泵浦功率密度的要求,设计了一种高缩束比的耦合系统。根据激光二极管（LD）的发光特性,将输出功率为80 kW的LD阵列进行拟球面排列,采用正交柱面透镜配合空心导光管进行泵浦耦合,耦合系统的面积缩束比高达86∶1。模拟计算表明,该耦合系统的耦合效率对导光管反射板的反射率依赖性较低,且脱离耦合系统后的泵浦光传输8.5 mm后,依然可以保持泵浦光场的轮廓,满足端面泵浦的常温Yb:YAG片状放大器对泵浦耦合系统的要求。     

Validity of Scalar Approaches to Radiation Modes of the GaAs-Based 1.3-μm Diode Lasers Designed for the Optical–Fibre Communication

The work presents a comparison between results of optical simulations based on the scalar and vectorial models applied to both stripe – geometry Fabry-Perot (FPL) as well as vertical-cavity surface-emitting (VCSEL) diode lasers designed for the 1.3-μm optical–fibre communication. As compared to vectorial optical approaches, scalar ones are known to be less exact but simultaneously they need as many as approximately 100 times shorter computation time, which favours those models in many applications. Therefore, vectorial models should be applied only in cases of confirmed faulty performance of scalar ones. While the Effective Index Method and the Effective Frequency Method have been chosen as scalar approaches to FPLs and VCSELs, respectively, simulations, the Method of Lines has been used in both cases as a vectorial one. Scalar models have been found to be quite exact in the case of a determination of the effective refractive index and wavelength of emitted radiation, whereas their exactness in the lasing threshold analysis is much worse, especially in the case of higher-order modes. Our analysis is concluded with the determination of the regions where both models give satisfactorily close results.     

激光二极管高效铜微通道冷却器设计

通过对铜微通道冷却器的散热分析,设计出５层结构的模块式铜微通道冷却器。采用常规的线切割工艺加工,散热通道宽大约200μm,深300μm,各层间用真空钎焊的方法组装。该冷却器对于腔长06mm、宽10mm的线阵激光二极管芯片热阻为0.58℃/W。通过面阵激光二极管封装实验证明,该冷却器可用于10％占空比工作的面阵激光二极管封装。     

利用皮秒脉冲激光驱动瞬态X射线激光

报道了利用皮秒激光驱动产生瞬态类镍银X射线激光的实验结果.采用一路脉冲宽度为数百皮秒的激光作为预脉冲，配合另一路皮秒激光作为主脉冲联合驱动平面靶，获得了一定强度的类镍银X射线激光输出，输出能量约为5—10nJ. 关键词： 瞬态X射线激光 长短脉冲联合驱动 皮秒脉冲激光     

半导体激光器光束准直系统的功率耦合效率

在长距离无线光通信中，接收点光功率密度与光束发散角平方呈反比关系，为了获得小的发散角和大的功率耦合效率，要求准直系统有较大的数值孔径(NA)，但数值孔径过大会增加像差，因此合理设计功率耦合效率与准直系统的数值孔径就非常重要。该文对半导体激光器光束准直系统中功率耦合效率进行了研究，给出了半导体激光器光束功率耦合效率与k(孔径半径与孔径处等效光束半径之比)的关系表达式，并结合激光器光束准直系统，给出了半导体激光器光束功率耦合效率与准直系统数值孔径的关系表达式。该研究结论对于半导体激光器光束准直系统设计具有参考作用。     

半导体激光器堆栈填充因子对慢轴光束准直的影响

为实现基于微透镜阵列的高功率半导体激光器堆栈光束整形,对带有快轴准直透镜的高功率半导体激光器堆栈慢轴光束准直技术进行研究。在慢轴光束准直理论分析基础上,着重研究了慢轴填充因子对其光束准直的影响,并对不同填充因子的半导体激光器慢轴光束准直方案进行了分析。针对实际使用的填充因子0.5的高功率半导体激光器堆栈采用以Bar条为单元进行整体准直设计,并采用基于空间扫描法的发散角测试装置对慢轴准直后剩余发散角进行测试,实现准直后剩余发散角半角2.12,实验表明该准直方法的有效性。     

Research and production of laser crystals in China

A general review of the progress in the research and production of laser crystals in China is presented. In the past quarter century, a considerable foundation and strength has been built up in this field and through further effort China's laser crystals will soon reach world level.     

Operational characteristics of dual gain single cavity Nd:YVO4 laser

Operational characteristics of a dual gain single cavity Nd:YVO₄ laser have been investigated. With semiconductor diode laser pump power of 2 W, 800 mW output was obtained with a slope efficiency of 49%. Further, by changing the relative orientation of the two crystals the polarization characteristics of the output could be varied. In particular by keeping the two Nd:YVO₄ crystals with their c-axes orthogonal to each other and adjusting the gain of the crystals so that both operate at approximately the same power level, completely unpolarized beams could be obtained.     

用于太阳光泵浦激光器的菲涅耳透镜设计方法

建立并分析了太阳光点聚焦型菲涅耳透镜的理论模型。提出了适用于太阳光泵浦激光器的设计方法。综合考虑会聚总功率和功率密度提高倍数两个因素,合理设计了菲涅耳透镜口径,相对孔径以及环形小棱镜的宽度(环距)三个参数,获得了用于太阳光泵浦激光器的菲涅耳透镜。     

高功率激光二极管阵列端面抽运放大器新型耦合方式研究

就高功率激光二极管阵列端面抽运大口径放大器提出一种新的耦合方式：激光二极管阵列拟球面排布,其后紧接一个导管进行耦合传输. 用三维光线追迹法对这种耦合方式的特性进行模拟分析. 结果表明,该耦合方式能实现高的抽运耦合效率和高的能量沉积效率,在面积缩束比为30的条件下,该耦合方式的耦合效率和能量沉积效率最高可分别达96.7%,93.7%;当激光二极管面阵单元发光区域不小于导管输出端口径时,该耦合方式能实现抽运场均匀平顶分布;另外,采用该耦合方式,激光二极管阵列排列方式灵活,非对称排布时也可实现两维对称性好、均匀平顶分布的抽运耦合场输出. 建立了激光二极管阵列端面耦合实验系统,实现了85.4%的耦合效率和均匀的抽运耦合场输出. 关键词： 激光二极管阵列抽运固体激光器 端面抽运 均匀抽运