激光二极管bar侧面泵浦Nd：YAG激光器热效应研究

从不同侧面泵浦方式的泵浦光强分布出发．依据热传导方程．求解出棒状激光晶体内的温度分布．计算出不同泵浦分布时的理论热透镜焦距．并进行热透镜实验。理论分析和实验表明，随着泵浦方向的增多，晶体内泵浦光强和温度分布越接近于轴向对称分布，热透镜更接近球面透镜。     

基于数字全息的热透镜效应测量

提出一种数字全息定量测量半导体激光二极管侧面泵浦Nd∶YAG晶体热透镜效应的方法。CCD采集Nd∶YAG晶体在不同泵浦电流下的数字全息图,通过数值重建得到热透镜效应引起的相位分布及其变化过程。再由相位分布计算得到对应的热透镜焦距。实验结果表明,利用数字全息技术可以准确和有效测量热透镜效应及热透镜焦距。     

固体激光棒热透镜焦距的测量

固体激光棒中的热透镜效应对激光器的性能有很大的影响.在固体激光器的热稳腔的设计中也需要知道激光棒的热透镜焦距的数值,因此测量激光棒的热透镜焦距是必要的和有意义的.我们采用类似于文献[1]中的方法,测量了三种常用的固体激光棒在泵浦期间和泵浦后,各个时刻的热透镜焦距的数值.在单脉冲泵浦期间,红宝石、Nd:YAG和钕玻璃三种激光棒的热透镜焦距均为负值. 测量热透镜焦距的原理如图1所示.设He-Ne探测激光束的束腰半径为ω0,束腰和光阑离热透镜的距离分别为d1和d2。ωn和ωm分别为存在热透镜(例如负透镜)和无热透镜时探测激光束到达光…     

干涉条纹法测量LD端面泵浦Nd∶YAG热透镜焦距

研究了端面泵浦Nd∶YAG晶体热透镜效应,提出了一种新的测量热透镜的方法 干涉条纹法,并通过理论估算与用此方法所测的热透镜焦距相比较,表明此方法所测热透镜焦距随着泵浦光功率的增大二者越来越吻合,验证了该方法的可靠性 该方法解决了端泵Nd∶YAG时,由温度梯度,热应力双折射和端面形变所引起的总的热透镜焦距难以测量的问题.     

干涉条纹法测量LD端面泵浦Nd∶YAG热透镜焦距

研究了端面泵浦Nd∶YAG晶体热透镜效应,提出了一种新的测量热透镜的方法-干涉条纹法,并通过理论估算与用此方法所测的热透镜焦距相比较, 表明此方法所测热透镜焦距随着泵浦光功率的增大二者越来越吻合, 验证了该方法的可靠性. 该方法解决了端泵Nd∶YAG时, 由温度梯度, 热应力双折射和端面形变所引起的总的热透镜焦距难以测量的问题.     

LD端面泵浦Nd∶YAG激光器中的热透镜焦距

采用热透镜焦距的理论计算与实验测量相比较的研究方法，得到一种端泵固体激光器出激光时的在线测量方法.通过建立热透镜等效腔模型以及腔型分析求解得出腔内光束束腰半径,用刀口法测出DPL腔外的远场发散角,根据发散角与透镜变换前后的束腰关系，得出LD端面泵浦Nd∶YAG激光器中的热透镜焦距.结果表明,通过上述方法所得结果与理论计算的热透镜焦距吻合,证实此方法准确、可行.     

激光二极管端面纵向泵浦Nd:YVO_4激光器的热效应研究

针对激光二极管端面纵向泵浦Nd:YVO4激光器,本文理论和实验详细研究了Nd:YVO4晶体的热透镜效应。在激光二极管的中心波长分别为808nm和880nm及分别采用单端端面纵向泵浦和双端端面纵向泵浦结构情况下,实验测量了Nd:YVO4晶体的热透镜焦距,实验结果和理论预测基本吻合。同时在泵浦功率60W时获得了18.8W的连续基横模激光输出。     

激光二极管bar侧面泵浦Nd∶YAG激光器热效应研究

从不同侧面泵浦方式的泵浦光强分布出发,依据热传导方程,求解出棒状激光晶体内的温度分布,计算出不同泵浦分布时的理论热透镜焦距,并进行热透镜实验。理论分析和实验表明,随着泵浦方向的增多,晶体内泵浦光强和温度分布越接近于轴向对称分布,热透镜更接近球面透镜。     

LDA侧面泵浦Nd:YAG激光器的热效应分析

 在高斯光强近似下对泵浦LD光强分布模型进行修正，建立了LDA侧面泵浦固体激光介质内热源分布的数值模型。用有限元法计算模拟了三角均匀分布侧面泵浦结构激光棒瞬态温升过程及稳态温度分布情况。讨论比较了泵浦源的高斯强度近似和均匀强度近似下激光棒内温度分布情况，并对激光棒的类热透镜的焦距进行实验测量。实验和数值计算说明了LDA泵浦结构和冷却场的非均匀分布使实际温度场偏离均匀泵浦时的二次曲线分布模型，激光晶体热效应产生的类透镜会聚作用的不对称导致了激光器输出光束质量在x，y方向上的不同。     

基于菲涅耳声透镜的声速与焦距的测量实验

将"空气中声速测量"实验和"薄透镜焦距测量"实验融合,设计了集声学原理和光学原理的"菲涅耳声透镜"实验,明确了该实验所使用的实验仪器,给出了实验内容,即测量声透镜的焦距、通过测量声透镜的几何参量得出超声波的波长、测量超声波在空气中的声速.最后,制作了焦距f为50mm的声透镜,并对实验内容进行了可行性分析及实验验证.实验结果(声透镜的焦距为50.3mm及超声波波长值8.70mm)与理论设计值基本一致.     

Thermal lens determination of LD end-pumped solid-state laser with stable resonator by slit scanning method

A simple method to determine the thermal focal length of LD end-pumped solid-state laser with stable resonator is presented. The M² factor describing the quality of the beam can be obtained by scanning a slit through the multi-mode Gaussian beam field. The waist width of the beam and the corresponding TEM₀₀ under the same parameters of laser are then deduced through the law of multi-mode Gaussian beam propagation. Based on the standard matrix theory of stable resonator, the thermal focal length of the gain medium can be easily achieved. To show the application of this approach, the thermal focal length of an LD pumped Nd:YVO₄ laser is measured and the experimental results are in agreement with the theoretical prediction.     

纵向泵浦固体激光介质热透镜效应的理论研究

 在分析了纵向泵浦、周边致冷固体激光棒内加热及冷却机理的基础上,将热传导方程合理简化为一维形式,求解出以级数方式表达的棒内温度分布。并根据热弹性力学原理,获得了激光棒中热致应力场和应变场。在考虑了与热透镜效应有关的三个因素：即热色散、热致应力双折射和端面变形后,推导出了纵向泵浦固体激光棒有效热焦距的解析表达式。将所获结果运用于常用的激光晶体Nd:YAG,发现当使用10W半导体激光器泵浦时,所产生的有效热焦距在毫米量级。     

基于哈特曼-夏克波前测量原理的焦距测量

本文从哈特曼-夏克波前测量原理出发,提出了基于波前测量的透镜焦距测量方法|得到了使用这一方法测量焦距的计算公式.使用633 nm和780 nm两种波长的半导体准直激光器作为光源,测量了三片双合透镜的焦距,结果表明,633 nm光源下测量得到的波长与透镜的设计焦距值相吻合,能够正确测量透镜焦距|而780 nm光源的测量结果显示出较大的相对测量偏差,但可用于评估透镜的剩余球差、色差以及制造公差.     

Thermal lensing of diode side-pumped solid-state lasers

The pump energy distribution in a diode side-pumped solid-state laser, is an overlap of propagating Gaussian beams. A simple model has been developed to calculate the thermal focal length of a diode side-pumped solid-state laser, which is based on a thermal model with a Gaussian heat density in any cross section of a laser rod. It can be seen that as the waists of pump beams increase, the energy distribution tends to be uniform and the thermal focal length tends to be long, which means a smaller thermal focusing.     

Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd∶YVO4 Lasers

According to the resonator transform circle theory, the focal length of thermal lens of laser media in laser diode end-pumped solid-state lasers is analyzed and measured with a simple method. A 30W 808nm LD pumped YVO4 laser is developed and characterized.     

Measurement of Thermal Lens Focal Length and Its Effect on Laser Output Characteristics in LD End-pumped Nd:YVO4 Lasers

According to the resonator transform circle theory, the focal length of thermal lens of laser media in laser diode end-pumped solid-state lasers is analyzed and measured with a simple method. A 30W 808nm LD pumped YVO4 laser is developed and characterized.     

Investigation of the beam propagation in a pumped laser rod

A method investigating the beam propagation in a pumped laser rod is proposed. In this method, the pumped laser rod in a resonator is evenly divided into N segments along the laser rod axis, and each segment is considered as a small thermal lens with thermal focus length of f. Accordingly, the beam radius distributions in the laser rod for the symmetric and asymmetric resonators are thus calculated, respectively. The beam radius distribution in the whole resonator is also calculated. Moreover, the calculated beam distribution in the whole resonator and in the rod is also described in detail.     

Nd:YAG薄片激光器热致波前畸变

 理论分析了激光二极管端面泵浦薄片Nd:YAG 激光器的激光介质热效应对波前相位分布的影响，给出了薄片激光器波前热畸变的计算公式。数值模拟了理想均匀泵浦及4阶超高斯泵浦下的波前分布，分析了介质厚度和泵浦均匀性与波前畸变量的关系。研究表明，介质越薄，激光泵浦光均匀性越好，泵浦功率密度越小，激光波前畸变越小；与介质厚度、泵浦功率密度相比，泵浦光光强分布对波前的影响更为显著。     

半导体可饱和吸收镜被动锁模侧面抽运Nd:YAG激光器研究

利用半导体可饱和吸收镜(SESAM)锁模技术实现的超快脉冲激光器具有结构简单紧凑、脉冲序列稳定等优势,在许多领域有着重要用途,自问世以来受到国内外的广泛关注.分析了SESAM被动锁模侧面抽运固体激光器的具体要求,进行了不同条件下的SESAM被动锁模侧面抽运Nd:YAG激光器实验.获得了最高平均功率9.5 W,脉冲重复频率71 MHz,单脉冲能量约141 nJ的皮秒激光脉冲.对SESAM被动锁模侧面抽运Nd:YAG激光器进行了实验和理论分析,对实现高功率连续超短脉冲激光器进行了探讨.     

A simple method to determine the thermal focal length of solid-state lasers with rate equation

A simple method to measure the thermal focal length of solid-state laser with rate equation was presented. By measuring the output beam power of lasers, the beam waist of oscillating wave can be deduced from rate equation under the stable oscillation condition. Based on the ABCD matrix theory, the thermal focus of the gain medium was easily obtained. The thermal focus of a LD end-pumped Nd:GdVO₄ laser was measured and the experimental results agreed with the theoretical predication.