Properties of diode laser pumps for high-power solid-state lasers

Diode lasers used to pump high average power solid-state lasers typically have broad spectral width so that most of the pump light is not at the peak of the gain medium's absorption feature. However, the long absorption length in these lasers enables even weakly absorbed light to pump efficiently. The result is that high absorption efficiency and improved pump distribution uniformity are possible when using realistic pump diodes. In addition, both quantities are nearly independent of the pump center wavelength.     

Efficiency of Nd laser materials with laser diode pumping

For pulsed laser-diode-pumped lasers, where efficiency is the most important issue, the choice of the Nd laser material makes a significant difference. The absorption efficiency, storage efficiency, and extraction efficiency for Nd:YAG, Nd:YLF, Nd:GSGG, Nd:BEL, Nd:YVO₄ , and Nd:glass are calculated. The materials are then compared under the assumption of equal quantum efficiency and damage threshold. Nd:YLF is found to be the best candidate for the application discussed here     

自聚焦透镜用于端泵浦DPL的耦合光学系统

本文用自聚焦透镜耦合ＬＤ输出，解决了需要短焦距、大数值孔径透镜的设计和制方面的困难。提出了计算自聚焦透镜耦合效率的简化模型。用自聚焦透镜和一对正交柱面透镜设计了一个耦合系统，并用该耦合系统端泵浦Ｎｄ：ＹＡＧ棒做了实验。     

High-power high-efficiency quasi-CW Sb-based mid-IR lasers using1.9-μm laser diode pumping

Power efficiency is a critical issue for mid-infrared (mid-IR) semiconductor lasers. Previously, the highest power and efficiency 4-μm laser was pumped with 0.98-μm laser diode. This letter used 1.9-μm diode pumping for better quantum defect ratio and heat flow geometry. A 3.7-μm InAsSb-AlAsSb laser yielded a pump-power-limited 1.25-W single-ended output in 1-ms-long pulse with 6.5% net optical-to-optical efficiency, in contrast with a 0.67-W thermally limited output and 2.7% efficiency with 0.98-μm diode pumping, at 70 K. The results are believed to represent the highest quasi-continuous-wave power from a single device, highest efficiency, and, scaled to the emitting aperture, highest power density for any 3-4-μm semiconductor laser for 1-ms pulse and ⩾70 K     

808 nm broad area DFB laser for solid-state laser pumping application

Wavelength stabilised 808 nm broad area distributed feedback (DFB) diode lasers with high continuous-wave (CW) output have been realised. The centre wavelength was locked at the Bragg condition with narrow spectral widths of 0.3 nm FWHM and shifted at a rate of 0.062 nm/°C. The 2 mm-long laser showed a record high 57% wall-plug efficiency and more than 4W CWoutput power at 25°C heatsink temperature. It is an ideal source for pumping solid-state lasers such as Nd-doped YAG and YVO₄.     

GaAs/GaAlAs diode lasers with angled pumping stripes

Operation of DH GaAs/GaAlAs stripe contact lasers with stripes oriented nonorthogonally to the cleaved end facets of the laser is described. Such lasers, with misalignment angles ofsim2deg, do not exhibit "kinking" behavior to power levels greater than 90 mW/facet, and do not exhibit relaxation oscillations under pulsed operation. Data showing the dependence of laser wavelength, spectral half-width, transverse mode structure, facet reflectivity, and output beam angle on both stripe angle and pump current level are also presented.     

Reducing pulse durations in diode pumped Q-switched solid-state lasers

The authors describe a subminiature, laser-diode-pumped, acoustooptic Q-switched Nd:YLF laser. The laser utilizes a very short cavity and laser crystal cooling to increase gain and reduce pulse width. Exploiting this technology results in 1.321 mu m pulses with durations and peak powers of 4.7 ns and 1100 W at 2 kHz and 8.7 ns and 250 W at 10 kHz in Nd:YLF. Similarly, 10 kHz pulses at 1.047 mu m have 2.7 ns duration and 1500 W peak power, also in Nd:YLF.<>     

Comparative study of the optical pumping efficiency in solid-state lasers

The optical pump efficiency of a solid-state laser has been calculated, in an unified manner, for the active materials ruby, Nd:YAG, Nd:glass, alexandrite, and Nd:Cr:GSGG under typical operating conditions. This unified presentation allows for a critical comparison and points toward possible future improvements.     

用于Rb蒸气激光泵浦的可调谐窄线宽半导体激光器

由于Rb蒸气的吸收峰随缓冲气体气压存在漂移,利用体布拉格光栅(VBG)实现线宽压窄的同时,实现泵浦半导体激光器中心波长的可调谐也是十分必要的。本文采用国内封装的半导体激光阵列(LDA),利用VBG的温度特性,实现了线宽不大于0.3nm的同时,激光器中心波长从779.89nm到780.35nm可调谐。该激光器可以通过叠阵方式用于Rb蒸气的泵浦和激励。     

高亮度半导体激光器泵浦光纤耦合模块

采用一种阶梯排列结构的单管激光器合束技术制成了高亮度半导体激光器光纤耦合模块,可用于泵浦掺Yb3+大模场双包层光纤激光器。利用微透镜组对各单管半导体激光器进行快慢轴准直,在快轴方向实现光束叠加,然后通过两组消球差设计的柱面透镜组分别对合成光束快慢轴方向进行聚焦,耦合进入光纤。实验中将6只输出功率为6 W 的976 nm单管半导体激光器输出光束耦合进芯径为105 m、数值孔径为0.15的光纤中,当工作电流为6.2 A 时,光纤输出功率达29.0 W,光纤耦合效率达到80.1%,亮度超过4.74 MW/cm2-str。     

RbCl:Li color center laser with laser diode pumping

CW operation of a RbCl:Li-F_A(II) laser has been obtained under pumping by a red laser diode. Pump power at threshold is 90 mW. Single frequency operation of the color center laser has been achieved. The intensity noise generated by two pump sources (laser diode and Kr-ion laser) is compared     

球面分布的半导体激光二极管阵列泵浦结构的研究

一个用来泵浦的半导体激光二极管堆栈包括8个半导体激光二极管阵列。这些阵列排布在一个球面上,每个bar条的输出激光被离轴压缩来实现高效率的耦合。半导体激光二极管堆栈的输出光束由一个空心导光管耦合到激光工作介质上。针对用于耦合半导体激光二极管堆栈的空心导光管进行了几何光学和光线追迹的分析。几何光学的分析揭示了耦合损耗的原因,并用来指导结构的设计。光线追迹分析结构参数和泵浦系统的输出特性,用来指导耦合系统参数的优化。模拟和分析结果表明,将半导体激光二极管阵列排布程球面可以提高偶和效率,降低最优化的导光管长度,改善输出能量场的分布。     

Spherical distribution structure of the semiconductor laser diode stack for pumping

A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution.     

一种LD侧面抽运固体激光棒光线追迹的数值计算

介绍了一种LD侧面抽运固体激光棒光线追迹的数值计算方法,并根据光线追迹公式编制了程序,画出了激光棒内光强的相对分布图。从光强的分布图可以看出,激光棒内光强的分布均匀。该程序使用方便、可行。     

New materials for flash-pumped organic lasers

Two compounds derived from 2-hydroxyquinoline were found to lase in the violet region of the spectrum when pumped by a flashlamp. Two aminocoumarin derivatives, under the same conditions, lased intensely in the range from 440 to 480 nm at a wavelength that depended on the addition of acid.     

固体激光材料研究的进展

本文评述了近期固体激光材料在高平均功率、高效率、可调谐、多波长等方面研究的进展。     

Development of Nd-doped solid-state laser materials for 944 nmoperation

We have grown neodymium-doped mixed apatite crystals [(Sr_1-x Ba_x)₅(PO₄)₃F, Sr₅ (P_1-xV_xO₄)₃F, and Ba ₅(P_1-xV_xO₄)₃F] and spectroscopically studied them as potential gain media for a laser source for atmospheric water sensing operating at 944.11 nm. We conclude that an appropriate apatite host material for a 944.11 nm laser should be a mixture of Sr₅(PO₄)₃F. With a small fraction of Ba₅(PO₄)₃F. Precise wavelength tuning around 944.11 nm can be accomplished by varying the host composition, temperature, and threshold population inversion. In apatite crystals of mixed composition, the amplified spontaneous emission (ASE) loss at 1.06 μm is predicted to be significantly smaller than that in the end members     

LD直接侧面泵浦棒状介质的光场研究

采用光线追迹的方法,建立了一套二极管直接侧面泵浦固体激光器的泵浦光场分布的数值模型,运用计算机进行模拟计算,分析系统结构参数对泵浦均匀性的影响,可为二极管泵浦固体激光器结构设计提供理论指导。实验测试了3种不同的侧面泵浦方式下激光介质的荧光分布图,所得结果与模拟计算结果基本相符,证实该数值模型得到的理论分析对二极管直接侧面泵浦固体激光器的结构设计和实验研究具有一定的指导意义。     

High-power operation of AlGaAs SQW-SCH broad-area laser diodes for Nd:YAG solid-state laser pumping

AlGaAs single-quantum-well separate-confinement-heterostructure (SQW-SCH) single-stripe broad-area laser diodes (LDs) for Nd:YAG solid-state laser pumping were developed. The high-power operation of the SQW-SCH LD was demonstrated. The maximum output power under continuous wave operation at room temperature was 2.6 W in the range of the Nd:YAG absorption band. Stable operation was also confirmed for over 500 h under the condition of 25 degrees C at 1 W under continuous-wave operation.<>