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.     

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。     

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.     

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     

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     

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.     

半导体激光泵浦固体激光器的新进展和应用前景

评述了半导体激光泵浦固体激光器的国际新进展及其在军事、工业和医学上的应用前景。综述了近年来DPL的国内进展, 内容包括用连续1 W LD端面泵浦和准连续60 W LDA侧面泵浦固体激光器的研究中得到的有关单纵模、调Q和锁模的结果。     

980 nm diode laser for pumping Er3+-doped fiberamplifiers

A high-power 980-nm diode laser, whose performance satisfies the requirements for pumping Er³⁺-doped optical fiber amplifiers, is described. The device is grown by atmospheric pressure organometallic vapor-phase epitaxy and contains a strained, step-graded In_0.25 Ga_0.75As/AlGaAs single-quantum-well active region. The threshold current of the ridge-waveguide laser is 8 mA, and a CW power output of 125 mW with a different quantum efficiency of 59% is demonstrated     

新环形半导体激光陀螺仪

介绍了一种新型半导体环形激光陀螺仪,它集合了传统He-Ne激光陀螺仪简单的结构方案和光纤陀螺仪成本低廉的优点。从理论上分析了该陀螺仪的精度,及其与各参数之间的关系,并提出了信号读出和转向判别的处理方法。最后,从集成光学的角度,给出了单片的半导体激光陀螺仪的设计结构。理论计算表明,当无源环形波导谐振腔的直径为40mm时,单片的集成光学半导体激光陀螺仪的精度可以达到0.032rad／s。     

Widely tunable Ce- and Er-codoped fluorozirconate fiber laser with 975-nm laser diode pumping

A spectrally narrowed widely tunable Ce/sup 3+/: Er/sup 3+/-codoped fluorozirconate (ZBLAN) fiber laser with a continuous-wave laser diode pumping at 975-nm pumping is demonstrated. Wide tunable range over 120 nm (1490-1610 nm) is attained by using a diffraction grating combined with a tuning mirror in the Ce/sup 3+/: Er/sup 3+/-ZBLAN fiber laser cavity. Rate-equation model analysis shows that the tunable range can expand further by using a wavelength-dependent reflectivity cavity mirror.     

Femtosecond solid-state lasers

The emergence of new ultrafast optical modulation techniques has opened the way towards a new femtosecond laser technology based on solid-state gain media. The authors address the requirements for stable ultrashort pulse generation in these novel femtosecond sources. The theoretical considerations are backed up by experimental results obtained with a number of different laser systems. The conclusions drawn from the presented theoretical and experimental investigations provide general guidelines for the design and optimization of a wide range of femtosecond solid-state laser oscillators     

Tunable solid-state lasers

Reviews the basic physics of tunable solid-state lasers and discusses the characteristics of the most significant established and emerging systems. Particular emphasis is placed on trivalent transition metals; alexandrite, other Cr-doped systems, and Ti: sapphire are also discussed. Other systems, rare earth and forsterite, are considered     

LD热弛豫时间与泵浦光谱效率的改进

采用测试半导体激光器热弛豫时间的新方法,测量光信号脉冲内不同时刻的时间分辨光谱,测试了TO封装和cm-Bar列阵的AlGaAs/GaAs半导体激光器泵浦光源,得到其热弛豫时间分别为为66 μs和96μs.在目前常用的方波驱动电流脉冲工作条件下,半导体激光器作为固体激光器泵浦源,如果热弛豫时间过长,单个脉冲内激射波长会偏离固体激光介质的吸收带,导致泵浦光波长利用率和有效泵浦能量降低.为克服现有技术的不足,文中提出了两种新型的驱动电流脉冲波形,通过优化电流波形参数可以将泵浦波长利用率提高30%左右,得到更大的有效泵浦能量.     

二极管侧面泵浦薄片激光器泵浦性能数值仿真

利用二极管侧面泵浦薄片激光器泵浦分布的对称性,通过泵浦分布中的特殊点对泵浦均匀性进行定量描述的方法,提出了由泵浦均匀性和吸收效率共同表征的泵浦性能指标,并使用该指标对一定范围内的阵列距离、圆薄片晶体尺寸和吸收系数的泵浦性能进行了对比。在一定取值范围内,当圆薄片晶体半径为13 mm、阵列与晶体中心间距为37 mm、吸收系数为0.10 mm-1时,泵浦性能指标达到最小值0.111 0。采用接近最优泵浦性能指标值的泵浦参数进行实验,初步测量了热效应造成的薄片相位畸变,根据泵浦分布计算出的相位畸变分布与实验结果基本相符。文中提出的泵浦性能指标和相应计算结果为薄片激光器的优化设计提供了理论参考。     

Rare-Gas pumping efficiencies for neodymium lasers

A comparison of rare-gas flashlamps for pumping YAG: Nd³⁺and neodymium-doped glass, which shows krypton lamps to be superior to xenon under certain circumstances, is presented. The emission spectra of argon have the best match to the neodymium absorption spectra, but argon lamps suffer from low radiative efficiency except at very high pressures. A detailed analysis of theoretical laser thresholds, which takes into account pump-pulse duration, cavity transfer coefficient, laser rod diameter, lamp emission spectra, and other pertinent parameters, is compared to experimental threshold data with good agreement. Krypton at 500-mm pressure gives a 19-percent improvement in the YAG : Nd³⁺threshold over a comparable xenon lamp at low current densities. Xenon is generally superior to krypton for pumping glass rods because of the greater absorption at 5900 Å where xenon is intrinsically a better radiator. However, proper lamp optimization shows a definite improvement in threshold with krypton at low drive levels. Xenon is anticipated to be superior to krypton at high current densities since line radiation will no longer contribute significantly to the pumping process. Proper optimization of lamp and cavity parameters should permit a slope efficiency of ∼6 percent for neodymium lasers to be realized.