半导体泵浦铯蒸气实现激光输出

采用线宽0.26nm的Littrow外腔巴条半导体激光器泵浦增益长度8mm缓冲气体为80kPa甲烷的铯(Cs)蒸气室,在Cs蒸气室温度120℃时,我们获得了394mW的894.6nm线偏振Cs蒸气激光,光光效率7.4%,斜率效率11.2%,阈值功率为1.72W。     

Fiber Optic Coupling of CW Linear Laser Diode Array

Based on a set of microoptics the output radiation from a continuous wave (CW) linear laser diode array is coupled into a multi-mode optical fiber of 400 μm diameter.The CW linear laser diode array is a 1 cm laser diode bar with 19 stripes with 100 μm aperture spaced on 500 μm centers.The coupling system contains packaged laser diode bar,fast axis collimator,slow axis collimation array,beam transformation system and focusing system.The high brightness,high power density and single fiber output of a laser diode bar is achieved.The coupling efficiency is 65% and the power density is up to 1.03×104 W/cm2.     

Fiber Optic Coupling of CW Linear Laser Diode Array

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大功率半导体激光器阵列热串扰行为

以硬焊料传导制冷,30%填充因子半导体激光器阵列为例,建立了三维有限元模型,对阵列内部各发光单元之间的热串扰行为进行了分析研究。结果表明,当其连续波工作时间大于1.2 ms后,阵列内发光单元之间出现热串扰现象;当次热沉由CuW合金改为铜金刚石复合材料时,阵列内发光单元自热阻和相邻发光单元的串扰热阻降低,有效地降低了各发光单元之间的热串扰行为。保持阵列宽度、发光单元数目及发光单元周期不变,发现随阵列填充因子的增加,器件热阻以指数衰减趋势逐渐降低,而发光单元间的热串扰特性对此变化并不敏感;保持阵列单个发光单元输出功率,发光单元尺寸及阵列宽度不变,增加发光单元个数后,阵列内各发光单元之间热串扰加剧,填充因子越高阵列升温速率越快;但在最初约70 s内,包含不同数目发光单元的阵列最高温度差异仅约0.5 ℃,有利于多发光单元高填充因子器件高功率输出。     

Narrow-wavelength-spread spectral combining laser with a reflector for a double pass with a single grating

We proposed a novel wavelength-spread compression technique for spectral beam combining of a diode laser array. A reflector, which is parallel to the grating, is introduced to achieve a double pass with a single grating.This facilitated the reduction of the wavelength spread by half and doubled the number of combined elements in the gain range of the diode laser. We achieved a power of 26.1 W under continuous wave operation using a19 element single bar with a wavelength spread of 6.3 nm, which is nearly half of the original wavelength spread of 14.2 nm, demonstrating the double-compressed spectrum capability of this structure. The spectral beam combining efficiency was 63.7%. The grating efficiency and reflector reflectance were both over 95%; hence, the efficiency loss of the double-pass grating with a reflector is acceptable. In contrast to double-grating methods,the proposed method introduces a reflector that efficiently uses the single grating and shows significant potential for a more efficient spectral beam combining of diode laser arrays.     

Frequency doubling with periodically poled KTiOPO4 at the fundamental wave of cesium D2 transition

We report the continuous wave (CW) second harmonic generation (SHG) with a periodically poled KTiOPO4 (PPKTP) pumped by a diode laser at 852.356 nm, which is exactly resonant on the cesium D2 transition.     

36 W侧面抽运腔内倍频Nd:YAG/KTP连续绿光激光器

通过优化平-凹-平三镜折叠腔结构设计,利用大功率半导体激光器侧面抽运、Ⅱ类相位匹配KTP晶体腔内倍频,获得高效高功率连续绿色激光输出.当抽运电流约为36 A时,得到最高36.6 W的连续绿光激光输出,对应的光—光转换效率为8.71％.在输出功率33 W时测量激光功率稳定性,其功率不稳定度为0.27%.用刀口法测量了激光器高输出功率时的光束质量,光束质量因子小于8.对高功率抽运情况下三镜折叠腔的像散补偿、失调灵敏度和基模在腔内分布情况做了数值模拟. 关键词： 侧面抽运 腔内倍频 连续波     

Thin Nd:YAG slab laser pumped by lens duct coupled diode laser stacks

High power continuous wave operation of a diode face-pumped thin Nd:YAG slab laser is reported. A novel pumping geometry for a thin Nd:YAG slab using cylindrical lens duct coupled diode laser stacks is demonstrated. In a close-coupled resonator, a maximum laser output power of 260 W in multimode operation is obtained. This corresponds to a slope efficiency of 34% and an optical-to-optical efficiency of 27%, respectively. In high-brightness operation, a polarized laser output of 70 W has been obtained with a beam quality factor close to 4 in both directions. The polarization contrast ratio is >100. PACS 42.55.Xi; 42.60.Pk; 42.60.By     

All-solid-state 543 nm green laser generated by frequency doubling of a diode pumped Nd:YVO<Subscript>4</Subscript> laser at 1086 nm

An efficient and compact green laser at 543 nm is generated by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode pumped Nd:YVO₄ laser at 1086 nm under the condition of suppression the higher gain transition near 1064 nm. With 10 W diode pump power and a frequency doubling crystal LBO, as high as 2.13 W of CW output power at 543 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 21.3% and the output power stability in 3 h is better than 2.27%.     

Enclosed laser ablation of 20 nm aluminium films using a continuous wave diode laser: II—Theoretical heating considerations and proposed mechanisms

Laser ablation using a 120 W continuous wave diode laser was carried out upon a thin aluminium layer which had been hermetically sealed between two layers of polymer. The results (presented in Part I) have shown that the film could be partially transparentised but with an efficiency which was far less than that seen for a Q-switched laser. In this paper, the thermal effects within the films are analysed and a mechanism by which enclosed surface laser ablation occurs is proposed.     

All-solid-state side-pumped intracavity sum frequency generation yellow laser at 589 nm with the output power of 11.4 W

A laser diode side pump all-solid-state pulse laser at 589 nm with high power and high conversion efficiency and small volume is demonstrated by intracavity sum frequency generation. By optimizing the cavity and adopting etalon techniques, a quasi continuous wave at 589 nm laser source, which has a maximum output power of 11.4 W, a repetition rate of 5 kHz, and a pulse width of 135 ns, is developed. The optical to optical conversion efficiency is up to 6.5% and the power stability is better than 2% in 8 hours.     

Fiber-coupled diode end-pumped Q-switched Tm,Ho:YLiF4 laser

At liquid-nitrogen temperature, at 10-kHz pulse repetition rate, Q-switched 36-ns pulses with average output power of 4 W at 2.05 μm and 4.5-W continuous wave output power with a total optical-optical conversion efficiency of 30%, were achieved from a 6% Tm, 0.5% Ho:YLiF4 laser. This laser was endpumped by a fiber-coupled laser diode emitting up to 15 W around 792 nm. The 1-m-long optical fiber carrying the pump radiation has a core diameter of 700 μm with a numerical aperture of 0.22.     

子午面大视场、孤矢面大孔径的耦合系统设计

本文提出了一套由４块柱面透镜组成的激光二极管阵列泵浦固体激光器的耦合系统，它可以将尺寸为４０ｍｍ×３．６ｍｍ的半导体激光二极管阵列的发光面所发出的子午面发散角±１０°，弧矢面发散角为±３０°的泵浦光耦合到接收面的系统可用于半导体激光二极管阵列泵浦固体激光器的研究。     

Efficient Nd:YVO_4 laser in-band pumped by wavelength-locked 913.9-nm laser diode and Q-switch operation

An efficient 1064-nm Nd:YVO_4laser in-band pumped by a wavelength-locked laser diode(LD) at 913.9 nm was demonstrated. The maximum continuous wave(CW) output power of 23.4 W at 1064 nm was realized with the incident pump power of 40 W, corresponding to a total optical-to-optical efficiency of 58.5%. This is to the best of our knowledge the highest total optical-to-optical efficiency and output power of Nd:YVO_4laser in-band pumped by a 913.9-nm laser diode.The Q-switched operation of this laser was also investigated. Through a contrast experiment of pumping at 808 nm, the experimental results showed that an Nd:YVO_4laser in-band pumped by a wavelength-locked LD at 913.9 nm had excellent pulse stability and beam quality for high repetition rate Q-switching operation.     

High-power continuous wave green beam generation by use of simple linear cavity with side-pumped module

High-power continuous wave green radiation has been generated by means of type-II phase-matched frequency doubling in a KTP crystal located in a simple linear cavity incorporating a diode side-pumped Nd:YAG laser module. The cavity was designed to make the fundamental beam radius at the KTP crystal smaller than that at the gain medium, as is required for obtaining large mode volume in Nd:YAG crystal and realizing efficient CW intracavity frequency doubling. Output power of 51.2 W is obtained in the experiment with a diode-to-green optical conversion efficiency of 10.3%. The M²-parameters of the laser are measured at different output powers. For the output power of about 47 W, the power fluctuation is measured less than 1%. The experimental results show that the continuous wave green laser system using this simple linear cavity offers good laser performance and output stability.     

808 nm高占空比大功率半导体激光器阵列

 采用渐变折射率分别限制单量子阱宽波导结构,通过降低非辐射复合、有源层载流子泄露、散射和吸收损耗来提高出射效率和降低激光阈值电流,从而提高半导体激光器阵列的输出功率;同时使P面具有更高的粒子掺杂数密度,优化N面合金条件,降低半导体激光器的串联电阻,降低焦耳热,提高了半导体激光器阵列的转换效率。利用金属有机化学气相淀积技术生长GaInAsP/InGaP/AlGaAs渐变折射率分别限制单量子阱宽波导结构激光器材料,利用该材料制成半导体激光线阵列在20%高占空比的输入电流下,半导体激光器的输出峰值功率达到189.64 W(180 A),斜率效率为1.1 W/A,中心波长为805.0 nm,阈值电流为7.6 A,电光转换效率最高可达55.4%;在1%占空比的输入电流下,阵列的输出峰值功率可达324.9 W(300 A),斜率效率为1.11 W/A,阈值电流为7.8 A,电光转化效率最高达55.6%,中心波长为804.5 nm。     

LD端面泵浦腔内倍频Yb:YAG绿光激光器

报道了一种激光二极管(LD)端面泵浦10at%掺杂Yb:YAG激光晶体(4×4×1mm)和Ⅰ类临界相位匹配LBO的腔内倍频全固态绿光激光器.为了克服"绿光问题",采用了两个激光二极管偏振耦合系统.在双路泵浦功率为1.2W时,获得最高功率为40mW525nm的连续基模激光输出.在腔内插入Cr4+:YAG饱和吸收体被动调Q,在泵浦功率为1.2W时,可以获得平均功率为5.2mW,脉冲重复频率为2.44kHz,脉冲宽度为51.5ns,峰值功率为41.7W的515nm脉冲激光输出.输出波长发生变化,而且515nm脉冲激光输出的阈值仅为728mW.     

包层泵浦的铒镱共掺光纤激光高效产生的实验研究

利用尾纤输出的977nm高亮度多模半导体激光器包层泵浦铒镱共掺双包层光纤,采用非球面透镜组耦合方式,使泵浦耦合效率达66%以上,并在法布里-珀罗激光振荡腔结构中实现了高效的连续激光产生,双包层光纤长度为2m,在泵浦入纤功率为1.36W时,输出连续功率最大394mW,斜率效率达35%,激光输出波长1.565μm.     

High power continuous wave Tm:YAP laser dual-end-pumped by laser diode at 795 nm

A high power continuous wave diode-pumped Tm:YAP laser at room temperature was presented in this paper. The Tm:YAP crystal with doped concentration of 3 at % for the experiment was c-cut with dimensions of 3 × 3 × 8 mm³. A 795 nm continuous wave laser diode in dual-end-pumped geometry was used to generate 1.94 μm laser output. At the pump power of 38.9 W, the highest output power reached 12.3 W by use of 15% output coupling, corresponding to optical conversion efficiency was 31.6% and the slope efficiency was 38.2%.     

All-solid-state continuous-wave frequency doubling Nd:LuVO4/LBO laser with 9.6 W output power at 672 nm

An efficient and compact red laser at 672 nm is generated by intracavity frequency doubling of a continuous wave (CW) laser operation of a diode pumped Nd:LuVO₄ laser at 1344 nm under the condition of suppression the higher gain transition near 1064 nm. With 38 W diode pump power and a frequency doubling crystal LBO, as high as 9.6 W of CW output power at 672 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 25.3% and the output power stability in 8 h is better than 2.38%. To the best of our knowledge, this it the highest conversion efficiency of watt-level laser at 672 nm generated by intracavity frequency doubling of a diode pumped Nd:LuVO₄ laser at 1344 nm.