纵向泵浦Cr∶ Nd∶GSGG激光棒的热透镜效应研究

对纵向泵浦Cr∶Nd∶GSGG激光棒的热透镜效应进行了详细的理论分析。对温度分布的函数表达式 ,进行了讨论 ;分析了热引起的应力 ,得到了激光棒破裂的临界功率公式 ;最后对光学畸变进行了分析与讨论 ,推导了光程差计算公式     

纵向泵浦Cr∶ Nd∶GSGG激光棒的热透镜效应研究

对纵向泵浦Cr∶ Nd∶GSGG激光棒的热透镜效应进行了详细的理论分析。对温度分布的函数表达式,进行了讨论;分析了热引起的应力,得到了激光棒破裂的临界功率公式;最后对光学畸变进行了分析与讨论,推导了光程差计算公式。     

激光棒热透镜效应的有限元分析

以热传导方程为基础,对热透镜效应补偿前后激光棒内部温度场与应力场的变化进行 分析。通过有限元软件进行模拟仿真和实验验证,实验结果与理论分析相符。     

管状激光介质的热透镜效应

从理论上详细分析了管状激光介质的热透镜效应,提出了“热感应光线轴”的观点,推导出确定管状激光介质光学性质的折射率分布、二维光线矩阵和热透镜焦距。     

侧面泵浦激光器热透镜效应的有限元分析

针对侧面泵浦的固体激光器工作介质产生的热透镜效应进行了分析,建立热传导方程。采用有限元分析的方法对不同泵浦条件下激光棒内的温度场和应力变化进行分析。提出补偿热透镜效应的有效措施。并通过实验对上述不同补偿条件下的热焦距进行测量比较。     

LD端面泵浦掺Nd晶体的热透镜焦距

采用He-Ne光直接测量的方法,在不同的泵浦功率下,对不同掺Nd晶体的热透镜焦距进行了测量,并对测量结果分析和讨论,为LD端面泵浦掺Nd晶体固体激光器的实验研究提供了数据参考。     

纵向泵浦的激光介质最佳长度

本文导出了纵向泵浦的激光介质最佳长度的数学表达式：Ｌｏｐｔ＝２／αｐ（１－πｈｃｗ＾２／τσλｐＰｐｏ·１／β），介绍了一种确定最佳长度的简单方法，并对某些理论和实验结果作了分析讨论。     

LD侧面泵浦固体激光棒新的热透镜焦距计算

在全固体激光器中,由于热沉积,因而产生热透镜效应。本文推导了一种半导体二极管（LD）计算侧面泵浦固体激光棒热透镜焦距的计算公式,并把它与通常使用的计算式进行了比较,发现这2个公式的曲线在基本吻合的情况下有一近似常值的差（约5～15mm）。理论分析了差异的原因,实验验证了我们推导的计算式比通常使用的计算式有更高的精度,能够更好地应用于固体激光器的设计。     

具有热透镜效应的LD端泵Z型腔的理论研究

由于采用大功率端面泵浦会在增益介质中产生热透镜效应,从而对激光器的运转产生严重的影响,本文利用端面泵浦固体激光棒有效热焦距的解析式得到谐振腔的稳区,并在考虑热透镜效应情况下对腔的参数和泵浦功率对稳区的影响进行讨论。     

LD泵浦固体激光器热透镜效应及优化设计的分析

LD泵浦固体激光器出现使激光器得到飞速发展,但是其在大功率运行时所表现出的强烈的热透镜效应,严重影响了激光器的稳定性和输出光的模式、光束质量.介绍了几种热透镜焦距fT和光束质量M2因子的估算公式,分析了热透镜改善的几种腔型设计.     

A flashlamp-pumped, Q-switched Cr:Nd:GSGG laser

A long-pulse Cr:Nd:GSGG laser was operated at almost 2 J output energy and almost 5 percent efficiency, using an uncooled pump cavity. An Nd:YAG rod in the same pump cavity produced 3.75 percent efficiency. Using a water-cooled pump cavity of standard design, the thermal focusing of Cr:Nd:GSGG was found to be almost six times that of Nd:YAG for the same flashlamp input energy. The thermal birefringence of the GSGG was also observed to be significantly higher than that of YAG. The performance of aQ-switched Cr:Nd:GSGG laser was characterized and compared to the predictions of a mathematical model for the laser. This yielded an estimate of4.2 times 10^{-19}cm²for the peak stimulated emission cross section of Nd³⁺in GSGG. Using the same technique for Nd:YAG yielded a value of9 times 10^{-19}cm².     

LD端面泵浦圆柱形Nd∶YAG晶体热效应研究

建立了圆柱形激光晶体的热传导模型.通过求解泊松方程,得到了在不同Nd离子掺杂浓度和不同泵浦光半径情况下激光晶体内的温度和温度场分布.研究结果表明,当其他条件不变时,随着Nd离子掺杂浓度的增加,Nd∶YAG晶体端面中心温度会升高,而晶体中心轴温度却会快速衰减.对于相同晶体,在泵浦功率一定时,随着泵浦光斑半径的减小,Nd∶YAG晶体端面中心温度会升高.如果采用低掺杂浓度的晶体作为增益介质,同时合理增加泵浦光斑半径,则可以有效抑制晶体的热效应.这一结论为提高激光器的稳定性、研究晶体的热效应提供了理论依据.     

LD端面泵浦圆柱形Nd：YAG晶体热效应研究

建立了圆柱形激光晶体的热传导模型。通过求解泊松方程,得到了在不同Nd离子掺杂浓度和不同泵浦光半径情况下激光晶体内的温度和温度场分布。研究结果表明,当其他条件不变时,随着Nd离子掺杂浓度的增加,Nd:YAG晶体端面中心温度会升高,而晶体中心轴温度却会快速衰减。对于相同晶体,在泵浦功率一定时,随着泵浦光斑半径的减小,Nd:YAG晶体端面中心温度会升高。如果采用低掺杂浓度的晶体作为增益介质,同时合理增加泵浦光斑半径,则可以有效抑制晶体的热效应。这一结论为提高激光器的稳定性、研究晶体的热效应提供了理论依据。     

晶体温度对L泵浦Nd：YVO_4／KTP腔内倍频激光器输出的影响

研究了ＬＤ泵浦Ｎｄ：ＹＶＯ４／ＫＴＰ腔内倍频激光器中激光晶体与倍频晶体的温度对器件基频与倍频输出的影响。用国产１Ｗ激光二极管作泵浦源,通过选择合适的Ｗｄ：ＹＶＯ４和ＫＴＰ的工作温度,在泵浦功率为６０４．２ｍＷ时获Ｔ得１３３．６ｍＷ的绿光输出,光－光转换效率为２２．１％。     

Thermal beam distortions in end-pumped Nd:YAG, Nd:GSGG, and Nd:YLFrods

The thermally induced beam distortions in end-pumped Nd:YAG, Nd:GSGG, and Nd:YLF rods were analyzed and the influence of edge- and face-cooling was investigated. The distributions of temperature, stress, and strain in the crystals were calculated by finite element analysis. Based on these data, the space-resolved changes of the refractive index were determined considering thermal dispersion, surface deformation, and strain-induced birefringence. The resulting optical path difference for one round-trip in the end-pumped rods was integrated numerically. For each rod, the induced thermal lens was determined over the extent of the pump spot radius. The calculations of the optical path difference were experimentally confirmed by investigations using a modified Twyman-Green interferometer with a polarized HeNe probe beam at 633 nm under lasing and nonlasing conditions     

Nd:GSGG激光晶体的光谱性能研究

用提拉法成功生长出了Nd3 :Gd3Sc2Ga3O12(Nd:GSGG)晶体,并对其光谱性能进行了研究.测量了晶体在400～2700 nm波段内的吸收光谱.用808 nm波长激发,测量了晶体的荧光光谱和荧光寿命,计算了晶体的发射截面.与Nd:GGG和Nd:YAG的光谱参数进行了比较.     

端面抽运矩形截面Nd:GdVO4晶体热效应研究

以解析分析理论为基础，研究矩形横截面Nd：GdVO4晶体受到具有高斯分布的端面中心入射时。激光晶体温度场分布情况和晶体抽运面热形变分布情况。通过对半导体激光端面入射Nd：GdVO4激光晶体工作特点分析。建立了符合激光晶体工作状态的热模型，利用热传导方程(泊松方程)的一种新求解方法，得出了矩形截面Nd：GdVO4晶体的温度场分布和端面热形变场通解表达式，同时对影响激光晶体温度场分布的各种因素进行了定量研究。研究结果表明，当使用输出功率为15W的半导体激光器端面中心入射Nd：GdVO4晶体(晶体掺钕离子原子数分数为1．2％)时，在抽运端面中心获得189．0℃最高温升和1．37μm最大热形变量。这种方法还可以应用到其他激光晶体热问题研究中。     

Growth and characterization of large Nd,Cr:GSGG crystals forhigh-average-power slab lasers

Nd,Cr:GSGG crystal boules up to 13 cm in diameter and 20.5 cm long have been grown by the Czochralski method. Several problems with Nd,Cr:GSGG growth were identified, and solved separately but not all at once; these problems included spiral boule growth, 1-μm absorption loss, iridium on the melt surface, iridium inclusions, boule cracking, dislocation, and fine scattering (smoke). In the grown crystals parameters relevant to their eventual use as gain elements for large slab lasers were measured including optical homogeneity, birefringence, absorption loss at 1 μm, scattering loss, and iridium inclusions. The optical homogeneity of the boules is good, except for a radial gradient in refractive index of about 10^-5 cm^-1. The birefringence is low (<3 nm/cm) in slabs cut from the boules. Scattering losses in the boules range from 0.01 to 0.08 cm^-1. This absorption has been reduced to <0.0025 cm^-1 in small samples using reducing heat treatments, but appropriate treatment conditions for full-scale slabs have yet to be determined     

激光二极管端面抽运矩形截面Nd:GdYVO4晶体热效应分析

研究了激光二极管(LD)端面高功率偏心抽运矩形截面激光晶体引起的热效应,提出偏心抽运矩形截面偏心度(ERS)的定义.通过求解周边恒温冷却Nd:GdYVO4激光晶体泊松热传导方程,得出了偏心度对晶体内部温度场的影响,以及温度梯度场的分布.研究表明:与中心抽运相比,偏心抽运时,激光晶体端面的最高温度有所降低,但温度梯度最高值升高,热畸变严重.     

Gain squaring in a Cr:Nd:GSGG active-mirror amplifier using acholesteric liquid crystal mirror

The small-signal gain of a Cr:Nd:GSGG active-mirror amplifier has been squared using a passive, 10-μm-thick, cholesteric liquid-crystal selective reflection mirror. This double/double-pass configuration was easy to align and solved difficulties, such as polarization leakage and back-reflection coupling, which had plagued previous multipass schemes. The mechanism for this gain squaring is explained in terms of the optical properties of cholesteric liquid crystals