多纵模激光F-P标准具双边缘测风可行性分析

讨论采用多纵模激光器作探测光源用于双边缘多普勒激光雷达测风的可行性。给出了多纵模激光器谐振腔腔长与边缘滤波器F-P标准具腔长之间的关系。分析了多纵模双边缘测风的主要特性,计算灵敏度、信噪比和径向测速误差,并与单纵模测风性能进行对比。可用类似单纵模测风中动态频率跟踪技术解决多纵模激光器频率漂移问题。     

Investigation of mechanism of free electron laser through spontaneous radiation spectrum

In this paper, the mechanism of free electron laser with a guide magnetic field is investigated by analyzing spontaneous radiation spectrum of electrons. The physical relation between spontaneous radiation and stimulated radiation in FEL with a guide magnetic field is studied. It is found that this relation in FEL is similar to that in quantum lasers. The spontaneous radiation spectrum is discrete. The frequency of stimulated radiation in FEL is oneselected and amplified in the radiation spectrum.     

Advantages of endoscopic laser arytenoidectomy using yag laser scalpel

The surgical management of bilateral vocal cord paralysis has been performed through an endoscope in the past. The etiology of bilateral vocal cord paralysis is usually secondary to trauma; to secure an adequate airway, a tracheostomy is performed. Endoscopic laser arytenoidectomy offers a safe method of decannulating patients with maintenance of good voice quality and a rima glottidis of 4–6 mm posteriorly. Several wavelengths are available to carry out this procedure, and this article will focus on Nd:Yag laser scalpel applications. The advantage of this method is the preservation of good voice quality with an option of an external procedure, if the need arises. The laser application offers excellent hemostasis, and decreased edema and scar tissue formation. The results of our study on 10 patients appear encouraging and superior with respect to other available wavelengths.     

脉冲激光诱导光纤损伤的测试方法

 针对传能光纤的高峰值功率激光损伤过程,研究了光纤损伤测试方法。实验装置搭建中增加了定位孔,有利于激光注入光纤对准;分别采用刀口法和CCD法对入射光束不同截面处光斑大小进行了测量,两种方法的测量结果基本一致。参考GJB1487-92激光光学元件测试方法和ISO11245光学表面的激光诱导损伤阈值测试方法,采用N-ON-1损伤测试和有效光斑面积计算方法对芯径为400 μm的石英包层阶跃折射率石英光纤进行了损伤阈值测试。实验发现：光纤损伤部位全部为入射端面,利用200倍显微镜观察光纤端面,出现明显永久性损伤点。最后采用统计学原理和线性拟合等方法得出测试光纤的端面零概率损伤阈值为3.85 GW/cm²。     

LD泵浦腔外倍频高转换效率Nd3+∶GdVO4固体激光器

通过合理设计精密调控各元件和温控电流，得到了平均功率为70 mW，脉冲宽度为22 ns，重复频率为14 kHz，峰值功率高达230 W的Nd3+∶GdVO4/Cr4+YAG红外脉冲激光器.先采用双凸透镜组合成的望远镜系统对1 063 nm的红外激光进行扩束，再对该光束聚焦，最后经双轴晶体LBO倍频后，得到了平均功率为40.6 mW，脉冲宽度为16 ns，重复频率为14 kHz，峰值功率高达181 W的绿光激光输出，1063 nm→532 nm的转换效率高达58%.测量了532 nm的光谱线宽曲线.解释了该聚焦方法比单一薄透镜效果明显好的原因，并指出了这种聚焦方法的使用对象.     

利用单模激光Lorenz系统实现混沌反控制

利用Lyapunov函数方法，对混沌反控制问题进行了研究.以单模激光Lorenz系统和描述心脏搏动的Bonhoeffer-Van der Pol系统为例，设计了一种控制器，成功地使Bonhoeffer-Van der Pol系统混沌化.给出了控制器的具体设计方案以及单模激光Lorenz系统与Bonhoeffer-Van der Pol系统状态之间误差系统的结构.仿真结果表明，在控制器的作用下，Bonhoeffer-Van der Pol系统所有状态变量严格地跟踪了单模激光Lorenz系统的混沌轨迹，对应的相空间中Bonhoeffer-Van der Pol系统的轨迹也由极限环转变为与单模激光Lorenz系统的轨迹完全相同的混沌吸引子，Bonhoeffer-Van der Pol系统严格地跟踪了单模激光Lorenz系统混沌的动态行为.     

利用射线追踪法研究超短外腔半导体激光器的输出特性

基于射线追踪法，推导了外腔半导体激光器的连续输出谱的隐函表达式.在此基础上，结合载流子速率方程，对超短外腔半导体激光器的输出谱及P-I特性进行了研究.结果表明：当外腔长度发生波长量级的变化时，超短外腔激光器的P-I特性将发生显著变化；随着外腔长度的变化，超短外腔激光器的激射波长在10nm范围内呈周期性跳变，当外腔长度介于40μm—70μm范围内，激射波长跳变范围最大.理论模拟结果与实验报道结果符合.     

LaMgAl11O19:Co2+被动调Q铒玻璃激光器研究

综述了被动调Q铒玻璃激光器的发展概况,推导了被动调Q铒玻璃激光器输出脉冲能量、脉宽的解析表达式,数值模拟了腔内损耗与输出脉冲能量、脉宽及峰值功率的关系以及输出脉冲能量与输入抽运能量的关系.设计了一台LaMgAl11O19:Co2 被动调Q铒玻璃激光器,实验验证了数值模拟分析结果.结果表明,腔内损耗增加将导致输出脉冲能量下降,脉宽变大,从而峰值功率降低.输入能量低于12 J时,输出只有单脉冲,当输入能量大于12 J时,输出会出现双脉冲.在8 J的电输入下,获得了峰值功率50 kW,2.7 mJ的1.535 tm激光输出.最后讨论了提高单脉冲能量的方法.     

高功率宽调谐范围掺Yb3+光子晶体光纤激光器

采用闪耀光栅作为色散元件,构建了前向、后向输出两种结构的可调谐掺Yb3 光子晶体光纤激光器,并对其输出特性进行了分析研究.在抽运功率5.75W时,前向输出结构实现了1050.6～1110.2 nm的连续调谐输出,光谱线宽约0.1 nm,边模抑制比大于44 dB.在调谐激光波长为1085 nm时,得到最高输出功率677 mW.结构改进的后向输出结构的可调谐输出结构在抽运功率4.43 W,调谐波长1075 nm,实现了2.21 W的功率输出,斜率效率为73%;调谐范围50.9 nm(1042.1～1093 nm),光谱线宽小于0.08 nm,边模抑制比大于50 dB.两种结构的可调谐激光器输出均为线偏振光,偏振度大于89.5%.     

Trends in microdisk laser research and linear optical modelling

Research into microdisk lasers demonstrates new achievements both in the technology and in the associated physical effects and applications. Melting and rounding of the disk edge boosts the Q-factors due to improved surface smoothness. In-plane cavity shape is widely used as a design instrument. Optimal shaping of pumped area lowers the threshold power. Photonic molecules made of several microdisks as “photonic atoms” show lasing at several closely spaced frequencies. A microdisk with a single quantum dot as an active region is considered as the most promising system for realisation of a single photon emitter necessary for quantum computing. These new effects and devices can be simulated with accurate numerical techniques, developed recently for “warm-cavity” linear modelling, that are able to bring a new vision of the physics of lasing.