A reliable high average power dye laser

A pulsed dye laser using commercial xenon flashlamps in a novel pump geometry and using thyristors for switching having an average laser output power capability of 100 W is described.     

Chirp control of a single-mode, good beam quality, zigzag dye laser

We report a substantial reduction of frequency chirp of a single-mode laser-pumped zigzag dye laser. A linear optical cavity using counterpropagating orthogonally polarized waves was injection-seeded at 568 mn and operated with a laser output of about 1 J. The chirp was controlled by an intracavity Pockels cell that was configured to add optical density at a rate which counterbalanced the decrease in optical density due to dye-solvent heating during the ~1-μs laser pulse. Heterodyne measurements were used to determine that the bandwidth was near the transform limit and chirp rate of ~1 MHz/μs. The beam quality of the laser was measured at 10 Hz as 1.7 XDL     

A 200 W average power, narrow bandwidth, tunable waveguide dye laser

A planar waveguide dye laser, driven by commercial xenon flashlamps with an average power output of 200 W at 50 pulse per second (pps) is described. Due to the planar structure, a narrow bandwidth operation down to 10 GHz has been obtained with a single grating arranged at grazing incidence. With this configuration, high overall efficiency up to 0.6 percent has been obtained, partially due to energy conversion of the broad-band emission spectrum of the flash-lamps by circulating an appropriate dye solution between flashlamps and reflectors.     

高平均功率电能激光器研究进展

高平均功率电能激光器在工业加工和定向能量传输、国防军事、激光钻油井等领域具有重要的应用前景.而且有效率高、结构紧凑灵活、热管理方便、后勤保障容易等优点.广泛关注了近几年来国外高平均功率电能激光器的研究进展,包括固体激光器、光纤激光器、液体激光器、自由电子激光器、碱金属蒸汽激光器、二氧化碳激光器及基于固体和光纤、半导体激光器的相干合成、非相干合成、光谱合成.在介绍了各种激光器工作原理和关键技术的基础上,详细分析了高平均功率电能激光器面临的技术挑战及未来的发展趋势.     

Design and characterization of a high average power slab YAG laser

The detailed design and characterization of a zigzag optical path laser with a0.6 times 2 times 15cm Nd:YAG slab is described. Beam distortions arising from nonuniform pumping of the slab and from various end effects are diagnosed, and the implementation of corrective measures is explained. We report on the device performance of the free running oscillator with 70 W output at 1.06 μm and the amplifier with parasitic suppression in which a small signal amplification of 45X was achieved.     

高亮度高平均功率固体激光器技术评述

综述了国外不同类型的高平均功率盘片激光器技术现状,分析和评述了各种途径的技术优势、技术限制、发展潜力及应用前景.最后介绍了应用电子学研究所高平均功率片状及固体热容激光器研究的最新进展.     

Single-mode operation of a zigzag dye laser

We report single-mode operation of a laser pumped zigzag dye laser for pulse lengths >1 μs with beam quality close to the diffraction limit. A unique linear optical cavity using counter-propagating orthogonally polarized waves was used. Laser efficiency measurements performed with a stable cavity had outputs of greater than 1.7 J at 568 mn using Pyrromethene-567 dye. The intrinsic laser efficiency was 55% with a slope efficiency of 77%. Single-mode operation was achieved using an unstable resonator with intra-cavity etalons to control the free running modes of the cavity and seeding with a single-mode Kr-ion laser operating at 568 nm. Heterodyne measurements were used to determine that the bandwidth was near the transform limit with the frequency chirping at a rate ~60 MHz/Ms. Far-field measurements of the beam quality indicated close to diffraction limited output     

Thermal effects of the operation of high average power Gunn devices

A lumped thermal resistance model is described for GaAs Gunn and LSA diodes. Thermal resistances are defined for the active layer, contact layer, bond interface, package and heat sink. This permits the calculation of tha maximum device temperature TM= T0+ P ΣiRiand the critical temperature difference across the active layer ΔTA= PRA. A transient analog incorporates thermal time constants Ti= RiCito consider high duty cycle pulsed operation. The carrier mobility is modeled as varying as1/Tin the range from 300 to 500°K. This permits thermal measurements based upon changes in resistance. The thermal calculations were also in agreement with blackbody infrared data. The mobility decline with temperature is shown to act as a link between the thermal profile and device performance. A thermally induced avalanching point, as well as device efficiency, are influenced by the peak-to-valley current ratio. This ratio is reduced from its theoretical value of over 2:1 by the active layer resistivity ratiobar{partial}/partial_{max}. Thus thermal gradients in the active layer act to create mobility gradients which alter the observed peak-to-valley ratio. The steps necessary for maintaining high average power efficient operation require low thermal resistances to minimize the active layer temperature gradients and a high current drop back ratio. Total experimental thermal resistances of 6.5°C/watt for an X-band CW diode and 17°C/watt for a thick LSA diode have been observed and fit the model presented.     

基于MOPA结构的高功率线偏振脉冲Yb光纤激光器

介绍了基于Nd3+:GdVO_4声光调Q激光器种子源和大直径Yb双包层保偏光纤作为放大介质的高功率线偏振脉冲光纤激光器.一个工作波长为808 nm的半导体激光器端面泵浦的、声光调Q的Nd3+:GdVO_4激光器输出重频在20～50 kHz、平均功率约3 w的高光束质量的1063 nm波长的激光,经过光学耦合系统和光学隔离器进入大直径Yb双包层保偏光纤作为光纤放大器的种子源,在波长为975 nm的半导体激光器泵浦下,光纤放大器获得了近衍射极限的、平均功率超过20 w、偏振抑制比超过14 dB的高功率线偏振脉冲激光输出.     

Single-mode operation of a repetitively pulsed dye laser

A Hansch-type dye laser pumped by a xenon ion laser achieves single-mode operation with a frequency jitter of 32 MHz and a peak power of 2 kW.     

高功率CO2激光器输出光束模式稳定性的研究

本文描述了横流CO_2激光器输出光束模式稳定性的影响因素,报导了采用8803型复合催化剂前后2kW CO_2激光器输出光束模式图样。     

高功率光纤激光空间拼接的研究进展

鉴于当前光纤激光空间拼接的研究成果,归纳出3种不同的拼接类型:利用转向镜的拼接、利用合束器的拼接和利用凹面光栅的拼接.对于每一种拼接方案,本文详细介绍了其实现的原理以及所采用的技术手段,并呈现了这些拼接方案所取得的阶段性成果.     

巨脉冲,大功率激光在近距离的动力学效应

用脉宽２０～５０ｎｓ，功率０．５ＭＷ的Ｎｄ：ＹＡＧ激光扩束聚焦，在近距离有动力学效应，距离越近，效应越强烈     

高平均功率太赫兹自由电子激光装置设计

为满足材料和生物医学等研究需要,中国工程物理研究院(中物院)提出了高平均功率太赫兹自由电子激光(THz FEL)用户装置研制项目。该装置采用准连续波运行的工作模式,太赫兹平均功率约为10 W。通过调节电子束能量和摇摆器的磁场强度,装置输出波长可在100μm(3 THz)~300μm(1 THz)进行调节,以满足不同用户的研究需要。装置主要包括电子源、主加速器、混合型摇摆器、激光谐振腔、太赫兹传输与探测系统等。装置将使用直流高压光阴极注入器作为电子源,主加速器为超导加速器,超导加速器后的电子束能量约8 MeV。该装置将建立成为一个用户装置。     

Single-mode operation of a long-pulse flashlamp pumped dye laser

We describe the achievement of single-mode operation of a flashlamp pumped long-pulse, ~700 ns dye laser, with output energy of about 350 mJ using a linear optical cavity with a “twisted mode” configuration. Measurements indicate that the laser frequency chirps by about 40 MHz over the entire pulse. Homodyne measurements indicate that the instantaneous bandwidth is close to the transform limit. This represents a significant advance in dye laser performance     

Output power saturation of BH laser under high current operation

Output power saturation of BH lasers under high current operation is analysed and it is concluded that such saturation is due to increase of leakage current through the burying layers. The mechanism of such leakage can be explained by a turn-on model of the bipolar transistor around the active region.     

Near-IR dye laser for diode-pumped operation

A dye laser pumped by AlGaInP laser diodes produced efficient, low threshold operation at wavelengths between 740 and 800 nm. Rhodamine 700, oxazine 750, DOTCI and oxazine 1 dyes were demonstrated. Optical conversion efficiencies approaching 50% and output power as high as 361 mW were obtained when pumping with a DCM-based dye laser. Parametric variations of the pump power and wavelength were performed over the range of 615 nm to 690 nm to provide a more complete characterization of the dye laser     

VRM腔高光束质量高功率双波长激光器

研制的双波长短脉冲激光器采用大模体积腔+渐变反射率输出镜技术,对二极管泵浦棒状激光介质产生的热透镜及热退偏进行补偿,在500 Hz下实现了谐振腔短脉冲能量140 mJ,脉宽约17.76 ns的1 064 nm激光输出,20 min能量不稳定性RMS值小于0.3%,激光光束质量M21.6。该实验结果与采用MOPA技术路线谐振腔+预放的方式技术指标相当,但采用谐振腔的技术路线结构简单紧凑。采用水热法生长抗灰迹效应的GTR-KTP晶体作为倍频晶体,相位匹配方式选择Ⅱ类相位匹配,倍频后532 nm激光单脉冲最高能量96 mJ,最高倍频效率68.6%,激光光束质量M22.1。通过能量调节设计,实现了线偏振态1 064 nm和532 nm激光功率连续可调共光轴输出。     

A high average power dual slab Nd:glass zigzag laser system

A dual slab Nd:LHG5 glass zigzag optical path laser was constructed with single-sided pumping and tested. A single slab (0.63 times 5.6 times 35cm) produced 80 W in an oscillator with an accompanying distortion of only 3 fringes (632.8 nm) as measured by a single-pass interferogram through the slab. Performance was achieved by producing uniform pumping and cooling of the slabs, and by controlling the distortion at the slab ends with pump shields.     

强激光束辐照下窗口材料热力效应数值模拟

基于三维瞬态热传导方程和弹性应力-应变方程,研究了空心环形强激光束(波长1.315μm)辐照下白宝石窗口温度、变形和应力的分布规律;研究了空心矩形强激光束(波长3.8μm)辐照下氟玻璃窗口温度、变形和应力的分布规律。采用三维有限元模型,数值模拟了强激光在窗口材料中产生的热和力学效应,为强激光窗口元件的选择以及热效应对光束质量影响的评估提供了参考。计算中,激光能量吸收采用体吸收,并考虑了光强分布的空间梯度以及光强在窗口内的衰减。