367 resultados para LD pumping


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固体热容激光器(SSHCL)作为高功率固体激光器的一个重要发展方向,引起人们广泛关注。数值模拟激光介质板条在热容方式下工作的温度和应力分布是了解该类激光器工作特性的一种有效手段,采用平面应力近似法导出了半导体激光器抽运热容激光介质板的二维温度和应力分布公式,同时也对二维抽运光吸收密度、介质板温度分布和折射率变化进行了分析与讨论。数值计算的结果表明二维效应的温度分布和应力分布要比一维效应给出的分布更均匀。

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为了实现光参变放大抽运光源高稳定输出的目的。通过对倍频过程的数值模拟分析,提出倍频中存在“稳定区”的概念,在基频光强一定的条件下(小于倍频晶体破坏阈值),通过非共线双程倍频的方式或串联倍频的方式可有效延长倍频晶体的有效作用长度,保证倍频工作区能够被控制在“稳定区”内,从而实现高稳定高转换效率的倍频输出。实验数据验证了这一结论,实验中,利用非共线双程倍频的方式使得倍频工作区在“稳定区”内,对波动±5.7%的1064nm高斯脉冲基频光,倍频光波动小于±2%,脉冲形状为高阶高斯脉冲,转换效率大于70%,实验结果

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The time response of optical switching properties of Sb thin films under focused laser pulses is investigated. The results show that the response course can be divided into onset, opening, and closing stages. Formulas for their lengths are given. The onset and opening times decrease with increasing pumping light power density. The closing time is about 150 ns. For optical memory, if the power density of the readout and recording lasers changes from 5 x 10(9) to 15 x 10(9) W/m(2), the onset time changes from 2.5 to 0.30 mus, and the opening time is on the nanosecond scale. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

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Within the framework of classic electromagnetic theories, we have studied the sign of refractive index of optical medias with the emphases on the roles of the electric and magnetic losses and gains. Starting from the Maxwell equations for an isotropic and homogeneous media, we have derived the general form of the complex refractive index and its relation with the complex electric permittivity and magnetic permeability, i.e. n = root epsilon mu, in which the intrinsic electric and magnetic losses and gains are included as the imaginary parts of the complex permittivity and permeability, respectively, as epsilon = epsilon(r) + i(epsilon i) and mu = mu(r) + i mu(i). The electric and magnetic losses are present in all passive materials, which correspond, respectively, to the positive imaginary permittivity and permeability epsilon(i) > 0 and mu(i) > 0. The electric and magnetic gains are present in materials where external pumping sources enable the light to be amplified instead of attenuated, which correspond, respectively, to the negative imaginary permittivity and permeability epsilon(i) < 0 and mu(i) < 0. We have analyzed and determined uniquely the sign of the refractive index, for all possible combinations of the four parameters epsilon(r), mu(r), epsilon(i), and mu(i), in light of the relativistic causality. A causal solution requires that the wave impedance be positive Re {Z} > 0. We illustrate the results for all cases in tables of the sign of refractive index. One of the most important messages from the sign tables is that, apart from the well-known case where simultaneously epsilon < 0 and mu < 0, there are other possibilities for the refractive index to be negative n < 0, for example, for epsilon(r) < 0, mu(r) > 0, epsilon(i) > 0, and mu(i) > 0, the refractive index is negative n < 0 provided mu(i)/epsilon(i) > mu(r)/vertical bar epsilon(r)vertical bar. (c) 2006 Elsevier B.V. All rights reserved.

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采用面泵浦的CAMIL结构,我们研究了970 nm泵浦的Yb:YAG/YAG复合陶瓷薄片激光器,获得了连续和调Q的激光输出。在连续运转情况下,获得了最高1.05 W的激光输出,中心波长为1031 nm,后腔输出镜透射率为2%。我们同时获得了声光调Q的脉冲输出,重复频率从1 kHz到30 kHz,脉宽分别从166 ns到700 ns。

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报道了半导体激光器端面抽运不同结构的声光调Q的双包层光纤激光器的脉冲输出特性.对前向、后向不同抽运方式的掺镱调Q双包层光纤激光器在输出平均功率,调Q脉冲宽度及脉冲稳定性进行了对比及讨论;其中后向抽运的光纤激光器,在10kHz重复频率调制下,获得了斜效率为60%的平均功率输出,其脉冲宽度为52ns,单脉冲能量为0·3mJ.最后利用不同抽运方式下的速率方程,理论分析调Q脉冲的特性,分析结果与实验相符.

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将千赫兹高功率全固态Nd:YAG激光器的增益介质当作厚透镜处理,使用矩阵的方法对等效热透镜腔进行分析。采用多条半导体激光列阵侧向紧凑抽运结构设计,提高了增益介质光抽运的均匀性。根据实际抽运功率,通过模拟计算,设计了平凸非稳腔。选择的凸面全反镜的最佳曲率半径有效地补偿了增益介质热透镜效应,激光器实现了动态稳腔运转,激光脉冲能量输出斜度效率大于13%,光束发散角优于1.3mrad。

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利用自制高功率激光二极管(LD)列阵堆和波导整形抽运耦合系统,将抽运光耦合至Nd:YVO4板条晶体,平平腔运转得到了1.064μm的偏振激光输出。在最大抽运功率为84W时,透过率为10%的输出腔镜得到了31W的激光功率输出,光一光效率37%,斜效率45%,板条晶体两个方向的输出光束质量差别较大。为了进一步提高光束质量,使用柱面镜混合腔结构,在最大抽运功率为86W时,得到了19.3W的1064nm激光输出,测得的非稳腔和稳腔两个方向的M^2因子分别为1.4和1.7。

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对激光二极管(LD)抽运固体激光器中大功率线阵激光二极管三向对称侧面抽运的漫反射腔结构进行了研究。激光器使用Nd:YAG作为激光晶体,电光器件材料为KD^*P晶体,漫反射体为陶瓷材料。实验表明,抽运光的利用率和均匀性有较大提高。在重复频率为10Hz下,实现了脉冲宽度8ns,最大平均功率为近2W的1064nm红外激光输出,激光器的效率有显著提高。

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为定量分析放大自发辐射(ASE)对调Q激光器性能的影响,在调Q激光速率方程中引入放大自发辐射项。并在合理的近似下求解,给出了激光二极管(LD)端面抽运电光调Q运转的固体激光器反转粒子数的建立过程,分析了放大自发辐射对激光上能级储能效率的影响及考虑放大自发辐射时调Q激光器输出脉冲宽度和脉冲能量随抽运功率的变化关系。结果表明,由于放大自发辐射的存在,上能级储能效率降低,且在一定的抽运功率下,调Q输出脉冲宽度变宽,脉冲能量下降。用LGS(La3Ga5SiO14)晶体作电光调Q元件,在激光二极管抽运的Nd:YVO

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报道了全固态激光器连续抽运高重复率电光调Q的实验和理论分析结果。用LGS(La3Ga5SiO14)晶体作电光调Q元件,在激光二极管(LD)端面抽运Nd:YVO4激光器中实现了较高重复率的电光调Q输出。实验中在10^4Hz重复率下,抽运功率为28w时,平均功率超过5W,脉冲宽度为7ns,峰值功率为70kW,并对不同重复率时的脉冲输出进行了比较,在低重复率下,脉宽〈6.5ns,峰值功率超过100kW。在理论上,通过对连续抽运时的电光调Q速率方程进行修正,并考虑放大自发辐射(ASE)的影响,对调Q激光器的储能过

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研究了激光二极管(LD)侧向抽运的Nd:YAG陶瓷电光调Q激光器的激光输出特性。该激光器采用九组激光二极管线阵列(LDA)侧面紧密环绕均匀排布的抽运结构,并用微通道热汇冷却技术冷却。在电光调Q方式下,重复频率为100Hz,抽运单脉冲能量为416mJ时,用尺寸为庐5mm×75mm,掺杂原子数分数为1%的Nd:YAG陶瓷棒,获得50mJ的1064nm激光输出,脉冲宽度为12ns,斜率效率达24%。并实验测量和分析了偏振片,KD^*P晶体,四分之一波片等调Q器件的插入损耗。测量了输出激光时间波形和光斑的光强空间

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针对抽运用激光二极管(LD)及其阵列单元,简要分析了温度对LD工作性能的影响,阐明了对阵列单元进行冷却处理的必要性,并总结了国内外近年来在激光二极管阵列㈣单元冷却方面的一些研究经验,包括传导辐射冷却法、热电致冷法和高效液体冷却器法。在此基础上,对各种冷却方法对应的温度控制技术、适用范围和优缺点分别进行了阐述。

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部分端面抽运的板条激光器是一种新型固体激光器.配合混合腔可以实现在大功率下保持高光束质量的激光振荡输出。谐振腔的腔镜倾斜是影响激光器输出特性的重要因素,快速傅里叶方法是一种快捷有效的计算方法,利用此方法模拟了腔镜倾斜对近场相位分布和远场光强分布的影响,并分析了光束质量的变化。理论分析表明,腔镜的小角度倾斜对近场相位影响较大,但对远场光强空间分布影响不大;随着倾斜角度不断增大,远场发散角和光束腰宽度也增大,光束质量虽然存在恶化的趋势,但光束质量因子肝值仍然较小,离轴非稳腔仍能保持高光束质量的输出。

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本文设计并实现了一台高重复率,紧凑型微脉冲全固态激光器。YAG晶体, Nd:YAG晶体和Cr4+:YAG晶体键合为一个单块晶体作为谐振腔。优化计算了Cr4+:YAG晶体的初始透过率,耦合输出透射率和泵浦光斑大小。对激光器的性能进行了测试,结果表明该激光器适合于空间激光测距。