A xenon ion pumped open dye stream laser

A pulsed xenon ion laser with an output power of 1 kW over the blue-green lines was used to pump an open dye stream laser. An efficiency of the order of 40 percent was determined in broad-band mode operation. The bandwidth in this case was 48 nm (from 582 to 630 nm).     

Design and analysis of spectral beam combining system for fiber lasers based on a concave grating

A novel fiber laser spectral beam combining scheme based on a concave grating is presented.The principle of the presented system is analyzed,and a concave grating with blazed structure for spectral beam combining is designed.The combining potential of the system is analyzed,and the results show that 39 Yb-doped fiber laser can be spectrally beam combined via the designed system.By using scalar diffraction theory,the combining effect of the system is analyzed.The results show that the diffraction efficiency of the designed concave grating is higher than 72% over the whole gain bandwidth,and the combining efficiency is 73.4%.With output power of 1 kW for individual fiber laser,combined power of 28.6 kW can be achieved.     

双波长脉冲可调谐染料激光器

描述激光泵浦双波长同时运转的可调谐染料激光器。使用R6G、R6G R640和R6G LD473混合染料,适当地选择分束器和带有布儒斯特棱镜组预扩束器的掠射光栅腔,可获得较宽的调谐区、低的放大的自发辐射背景,峰值功率可达40千瓦,输出线宽<0.22厘米~(-1),并具有偏振特性。     

A xenon ion pumped blue dye laser

A pulsed xenon ion laser with an output power of 5 kW at 364.5 nm has been used as a pump source for several blue dyes. Broad-band conversion efficiencies exceed 20 percent. The use of a birefringent filter provides tunable output in the blue region of the spectrum with a bandwidth of 0.08 nm and a pulsewidth of 120 ns.     

Broad-band diode-pumped ytterbium-doped fiber amplifier with 34-dBmoutput power

We investigate a high-power diode-pumped double-clad ytterbium-doped fiber amplifier with 34-dBm average output power and 1050-1095-nm bandwidth. A multidiode concentrator pumps the amplifier at 980 nm, with ~6 W of power launched into the inner cladding. Besides CW-signals, we amplify pulses from a mode-locked laser to 1 kW of peak power with only minor nonlinear distortions as well as pulses from a Q-switched laser to 50 μJ of energy. Reflections and backscatter limit the gain of the amplifier to 40 dB for a pump power of 2.5 W. For higher pump-powers than this, the amplifier started to self-Q-switch. The results are important for the development of cladding-pumped high-power fiber amplifiers     

Development of an S-band klystron with bandwidth of 11%

This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS).On the peak power level of 800 kW, the efficiency of klystron is more than 30%; the gain is more than 41 dB; the equal-driving relative instantaneous bandwidth is over 11%; the average power is larger than 8kW, and the power fluctuation within bandwidth is less than 1o5 dB.     

平均功率近2 W的被动锁模皮秒掺镱光纤激光器

报道了一个三级主振荡功率放大(MOPA)结构的瓦级皮秒光纤激光器.第一级利用半导体可饱和吸收镜(SESAM)和光纤光栅组成线性腔,构建了一个低功率的被动锁模掺Yb3+光纤激光器,其最大平均输出功率为9.2 mW,作为整个激光器的种子源;第二级采用单模掺镱光纤放大器对种子光进行预放大,得到108 mW平均输出功率;第三级采用带树状耦合器的双包层掺镱光纤放大器进行功率放大,获得了1.9 W平均输出功率.得到的脉冲脉宽36 ps,中心波长1064 nm,重复频率29.6 MHz,峰值功率1.8 kW,相应的单脉冲能量为61 nJ.实验中观察到种子源输出光谱中有一个凹陷,这是由于光纤光栅反射率过高并且带宽较窄引起的.     

高功率掺镱光纤振荡器:研究现状与发展趋势

近年来,高功率掺镱光纤振荡器的输出功率和光束质量不断提升,在工业、科研等领域得到了越来越广泛的应用。目前,多模掺镱光纤振荡器的输出功率已经突破17.5kW,近单模光纤振荡器输出功率已经突破8kW。本文对掺镱光纤振荡器在科研和工业领域的研究现状进行详细介绍,分析掺镱光纤振荡器未来的发展趋势;对进一步提升掺镱光纤振荡器功率和光束质量的各项关键技术进行剖析,给出了万瓦级近单模高功率掺镱光纤振荡器的技术方案,以期为更高功率光纤振荡器的发展提供技术参考。     

Single line high efficiency tunable fir generation by resonant four-wave mixing in CH3 pumped by a multiatmosphere tunable CO2 laser

By pumping CH₃F with a high pressure tunable TE-CO₂ laser, the resonant four-wave mixing process (RFWM) generates a very efficient tunable single line FIR emission at the Raman frequency. This result is strictly related to the spectroscopic structure of the CH₃F molecule. By means of this process, a tunable FIR emission on a 0.1 cm^?1 bandwidth 150 kW (8 mJ) single line, is obtained which can be used for many FIR multiphoton applications.     

Generation of high-power femtosecond pulse and octave-spanning ultrabroad supercontinuum using all-fiber system

We present the all-fiber system for amplification of high peak power femtosecond pulses. The 260-fs pulses are generated in the passively mode-locked Er-doped fiber (EDF) laser and amplified using the EDF amplifier system. The average and peak powers of the generated pulses are 215 mW and 43.2 kW, respectively, and the pulsewidth is 42.3 fs. Then the amplified pulses are coupled into polarization-maintaining highly nonlinear dispersion-shifted fiber and octave-spanning supercontinuum is generated. The spectral range is widely expanded from 980 to 2570 nm. To the best of our knowledge, this bandwidth is the maximum one in this wavelength region.     

Nd:YAG/Cr:YAG键合晶体的355 nm激光器

报道了一台基于Nd:YAG/Cr:YAG键合晶体的全固态355 nm紫外(UV)激光器的设计及实验结果.采用平-平腔结构获得高峰值功率、小束腰的1064 nm基频光.在谐振腔外,未聚焦的1064 nm基频光经KTP晶体倍频产生532 nm波长激光,二者再经LBO晶体和频获得355 nm紫外激光输出.实验中发现尽管Nd:YAG与Cr:YAG都是各向同性晶体,但在特定情况下输出的1064 nm基频光具有近似线偏振的特性,此特性可以有效地增加二次谐波产生(SHG)时基频光的利用率,从而提高整台激光器的转换效率.而基频光的谱线宽度及发散角也影响二次谐波及三次谐波产生(THG)的转换效率,需使其尽量在晶体的允许带宽及允许角范围以内.综合这几点因素,对激光谐振腔进行了仔细设计.当激光二极管(LD)抽运功率为8 W,激光器运行稳定时,基频光峰值功率达28 kW,最终获得平均功率为124 mW的355 nm紫外激光.     

100 kW DC biased, all semiconductor switch using Si P-I-N diodesand AlGaAs 2-D laser arrays

A two-dimensional laser array, delivering a peak power of 1 kW with an overall efficiency of 33%, was used to activate silicon p-i-n diodes. A single device, activated by a 1 kW laser, produced a holding voltage of 1000 V and conducted 56 A. When two similar p-i-n diodes were connected in parallel and activated by two 1 kW AlGaAs laser arrays, a holding voltage of 1000 V and conduction of 100 A were obtained     

Dual-Mode Terahertz Extended Interaction Oscillator Driven by a Pseudospark-Sourced Sheet Electron Beam

A terahertz dual-mode extended interaction oscillator (EIO) driven by a pseudospark-sourced sheet electron beam (SEB) was presented. The major advantages of the newly developed circuit include 1) high-density SEB interacting with the TM₁₁ and TM₃₁ modes, respectively, and 2) high output power of over 1 kW at the sub-terahertz frequency range. Two different types of 2π modes and their output characteristics were studied, and the circuit was optimized to ensure efficient outputs of two standing-wave modes. The three-dimensional (3D) particle-in-cell (PIC) simulation predicts the maximum output power of 1.3 kW with the 3-dB bandwidth of ~0.5 GHz at 303 GHz when operating at the TM₁₁ mode, and 3.18 kW with the 3-dB bandwidth of ~0.85 GHz at 364 GHz when operating at the TM₃₁ mode.     

连续氩氪离子激光晶化非晶硅薄膜的研究

为了研究连续激光晶化非晶硅薄膜中激光功率密度对晶化效果的影响,利用磁控溅射法制备非晶硅薄膜,采用连续氩氪混合离子激光器对薄膜进行退火晶化,用显微喇曼光谱测试技术和场发射扫描电子显微镜研究了薄膜在5ms固定时间下不同激光功率密度对晶化效果的影响,并对比了普通玻璃片和石英玻璃两种衬底上薄膜晶化过程的差异。结果表明,在一定激光功率密度范围内(0kW/cm2~27.1kW/cm2),当激光功率密度大于15.1kW/cm2时,普通玻璃衬底沉积的非晶硅薄膜开始实现晶化;随着激光功率密度的增大,晶化效果先逐渐变好,之后变差;激光功率密度增大到24.9kW/cm2时,薄膜表面呈现大面积散落的苹果状多晶硅颗粒,晶粒截面尺寸高达478nm ;激光功率密度存在一个中间值,使得晶化效果达到最佳;石英衬底上沉积的非晶硅薄膜则呈现与前者不同的结晶生长过程,当激光功率密度为19.7kW/cm2时,薄膜表面呈现大晶粒尺寸的球形多晶硅颗粒,并且晶粒尺寸随着激光功率密度的增大而增大,在 27.1kW/cm2处晶粒尺寸达到最大5.38m。研究结果对用连续激光晶化法制备多晶硅薄膜的研究具有积极意义。     

高功率激光系统中内光路热变形的仿真及实验研究

为了研究高功率激光系统中的内光路热变形累积效应对光束质量的影响，开展了理论和实验研究。首先，选择三种非稳腔输出的典型高功率激光，激光功率分别为10 kW、50 kW和100 kW，通过热动力学瞬态方法的有限元分析对激光照射的反射镜进行热变形分析。然后，利用光线追迹理论得到激光的波前像差。最终，激光远场光束质量中的Strehl比，因子可以通过Fresnel衍射积分进行计算和对比分析。仿真结果表明，由于内光路反射镜的热变形，远场光束将出现偏心和像散的现象，其中心光强及会聚能力均会下降。随着内光路反射镜的增加，Strehl比减少而因子增加，远场光斑x方向的倾斜、像散及彗差也会逐渐增加，将成为系统的主要像差。为了和上述理论仿真结果进行对比，建立了一个测量反射镜热变形实验平台，实验中采用10 kW的TEA CO2激光器照射99%反射率的铜反射镜，通过等效放大原理，实验结果可以部分代替50 kW和100 kW功率水平。镜面热变形的测量精度小于/15，并和仿真结果吻合得较好。结果表明，反射镜的热变形在激光功率超过10 kW时不能被忽略，且随着激光功率及反射次数的增加，这种热畸变将变得越发严重。所得结果将对高功率激光系统的热畸变分析过程提供指导，并可应用于激光核聚变及激光武器系统等的设计分析中。     

激光辐照下金属/炸药结构温度场的数值模拟

为了分析不同功率激光对金属/炸药结构内部温度分布的影响以及炸药爆炸的可能性,利用有限元软件,考虑金属材料的物性参量和钢靶表面能量耦合系数随温度的变化规律,建立了在功率分别为55kW,60kW和65kW的激光辐照下金属/炸药结构的3维温度分布模型,得到了光斑中心轴线方向温度分布和金属表面中心及金属与炸药接触面的温度随时间变化曲线,在55kW,60kW和65kW 3种功率不同的激光辐照下,5s末炸药表面的温度分别为521K,550K和581K。结果表明,功率越大炸药获得的温升越大越易引起爆炸,功率增加时炸药获得的温度增量在不同时刻有所不同,在一定辐照时间内,炸药的温升发生在与金属接触的小区域内。这对激光辐照金属/炸药结构的深入研究具有指导意义。     

激光热处理宽带光斑的研究

本文研究了激光热处理光斑形状对宽带硬化性能的影响,给出了千瓦级和万瓦级激光宽带光源方案。     

脉冲激光热力冲击效应对电沉积的作用

脉冲激光电化学复合沉积利用激光的热力冲击效应可以有效提高沉积效率,改善加工质量。在所构建的纳秒脉冲激光电化学沉积加工系统中,利用激光辐照和电化学沉积的方法对铜进行了复合沉积试验。分析了激光的热力冲击效应对电沉积的作用机理,激光产生的力效应使阴极基片发生弹性变形,改变了电极电势和电流密度,提高了电沉积质量。通过加工试验,研究了激光平均功率密度对沉积质量和沉积效率的影响,并进行了讨论。试验结果表明,激光平均功率密度介于100~400 kW/cm2时可以获得较好的沉积层质量。激光平均功率密度在200 kW/cm2左右,沉积速率取得最大值。     

X波段100kW宽带大功率多注速调管

介绍了一种X波段宽带大功率多注速调管。该速调管工作于TM220高次模式,采用四组28个电子注栅控电子枪结构,为保证整管的输出带宽及增益采用多腔参差调谐结构高频段及多级滤波器输能系统,为实现满工作比7%工作采用电磁线包聚焦。测试结果其输出带宽达到300MHz,峰值输出功率达到100kW,平均输出功率达到7kW。     

脉冲氙离子激光器泵浦的可调谐染料激光器

脉冲氙离子激光器具有高功率输出和较长的激光脉冲宽度,而且结构简单,用它来泵浦可调谐染料激光器,引起了人们的兴趣.H(?)nsch等首先用氙离子激光器泵浦若丹明6G染料,获得了染料激光输出,以后Laird.D.Schearer等作了进一步的研究.采用染料快速流动可获得高达40%的转换效率,利用氙离子的紫外输出谱线,还可将染料激光器的输出扩展到紫外波段.