高能重复频率运转条件下等离子体普克尔盒热效应及其控制理论分析

在高能重复频率运转的激光系统中,用作激光隔离、多程放大控制的关键单元普克尔盒遇到了通光口径限制与热效应的双重挑战。采用等离子体电极技术将普克尔盒定标到大口径,通过选择吸收系数小且通光方向薄的KD*P作为电光晶体以减少对激光的吸收,并在此基础上数值分析了等离子体普克尔盒的热效应。提出了端面传导冷却电光晶体的热管理方法,并进行优化设计。数值模拟结果显示,采用单块白宝石传导冷却2块KD*P,普克尔盒的驱动电压可降低至27 kV。在平均功率密度35 W/cm2的激光持续辐照下,端面传导冷却的40 mm×40 mm口径等离子体普克尔盒全口径内最大退偏损耗为0.22%,波前峰谷(PV)值为0.60λ。     

Half watt average power at 25 kHz from fourth harmonic of Nd:YAG

A half watt of 266 nm radiation has been generated at a pulse rate of 25 kHz by using KD*P and KTP crystals to frequency quadruple a CW-pumped, acoustoopticQ-switched Nd:YAG laser.     

电光调Q双脉冲输出Nd:YAG全固态激光器

设计了激光二极管(LD)双端面抽运传导冷却复合Nd:YAG晶体电光调Q激光器,实现脉冲间隔可调的双Q脉冲输出。用两个光纤耦合输出的LD模块作为抽运源,偏硼酸钡(BBO)晶体作为Q开关,在一个抽运周期内两次启动Q开关,获得脉冲能量大于14mJ,脉宽小于等于18ns,脉冲间隔200～230μs可调的双Q脉冲输出,激光器重复频率50Hz,光-光转换效率达到24%。探索了用磷酸二氘钾(KD*P)调Q晶体开关实现稳定双脉冲输出的可行性,通过抑制压电环效应,消除子脉冲现象,最终获得脉冲能量约11mJ,脉宽小于等于18ns。     

砷酸二氘铯(CD~*A)晶体的倍频效应

我们使用CD~*A晶体对Nd:YAG激光进行了倍频实验.并与ADP、KDP、KD~*P、LI等晶体(本所生长)进行了比较.实验结果表明CD~*A晶体是对高功率钕激光的良好倍频材料.实验使用Nd:YAG脉冲激光器,电光调Q,无放大级.1.06微米激光峰值功率20兆瓦(133兆     

Absolute and relative nonlinear optical coefficients of KDP, KD*P,BaB2O4, LiIO3, MgO:LiNbO3,and KTP measured by phase-matched second-harmonic generation

Both absolute and relative nonlinear optical coefficients of six nonlinear materials measured by second-harmonic generation are discussed. A single-mode, injection-seeded, Q-switched Nd:YAG laser with spatially filtered output was used to generate the 1.064-μm fundamental radiation. The following results were obtained: d₃₆(KD*P)=0.38 pm/V, d₃₆(KD*P)=0.37 pm/V, |d₂₂(BaB ₂O₄)|=2.2 pm/V, d₃₁(LiIO₃ )=-4.1 pm/V, d₃₁(5%MgO:MgO LiNbO₃)=-4.7 pm/V, and d_eff(KTP)=3.2 pm/V. The accuracy of these measurements is estimated to be better than 10%     

折返点匹配的宽带二倍频实验研究

在二次谐波转换中,基频光和倍频光的群速失配是限制转换带宽的主要因素。利用折返点匹配的宽带谐波转换技术能同时实现基频光和倍频光的相位匹配和群速匹配,理论计算表明在折返点匹配的情况下,倍频转换带宽将显著增加。分别利用厚度10 mm,氘含量12%的KD*P晶体和厚度12 mm的KDP晶体对中心波长为1053 nm,谱宽为31 nm,能量为620μJ的基频光进行折返点匹配二倍频和传统二倍频的对比实验,前者取得了22 nm的转换带宽,远大于后者7 nm的转换带宽。实验结果证实了理论计算的正确性,显示了折返点匹配宽带谐波转换技术的优越性。相应地,前者转换效率为25%,大于后者20%的转换效率,导致倍频转换效率较低的主要因素是入射基频光的光束质量和光谱质量较差。     

Pulse measurement of r63? in KD*P

A subnanosecond voltage generator has been used to measure the zero-strain electro-optic coefficient r63? of KD*P, and a value of 24.0×10?12 m/V±5% has been obtained.     

90 degree phase matched generation of 266 nm light in 90 percent deuterated KD*P

Experiments have been performed to determine the temperature necessary to achieve 90° phase matched generation of the fourth harmonic of a Nd:YAG laser in 90 percent deuterated KD*P. A phase matching temperature of 62°C was found.     

Optical parametric amplification

This paper presents a detailed theoretical and experimental study of optical parametric amplification. Experimental measurements in KD*P pumped at 354.7 nm and LiNbO3pumped at 1064 nm by aQ-switched Nd:YAG source are in excellent agreement with theory. The large gains, high conversion efficiency, and wide tuning range make optical parametric amplification an important method for power generation in the optical and infrared spectral range.     

Temperature dispersion in ADP, KDP, and KD*P for nonlinear devices

Lack of proper temperature dispersion data prevented many experimenters from interpreting tuning curves for various parametric interactions using KDP, KD*P, and ADP. We present here a formulation to present temperature dispersion which can predict accurately the temperature dependence in phase-matching behavior of such crystals.     

氟氯系列折射率匹配液的研究和应用

研究了氟氯系列折射率匹配液,测量并考核了其各项性能。结果证明该系列和KD~*P电光晶体能达到比氟碳系列更精细的匹配。降低了晶体界面的反射达20多倍,透过率增加10％以上,在冰洲石棱镜表面的匹配也取得满意的效果。     

不同几何结构电光偏转器比较研究

为了发展性能优良的电光偏转器,采用傍轴近似分析了级联棱镜电光偏转器的折射率梯度等效表达式,总结出了不同几何结构电光偏转器的偏转角和偏转轨迹公式,在此基础上比较研究了4种不同几何结构电光偏转器的偏转特性和偏转轨迹,比较分析了梯形、喇叭形和抛物线形几何结构电光偏转器的偏转灵敏度,为较大角度电光偏转系统的设计提供了有意义的参考。     

Digital light deflectors

Several electrooptic digital light deflection techniques have been proposed. The maximum number of resolvable deflection positions for all methods is determined, essentially, by economic reasons, the tolerable amount of background fight, and aberrations. In this paper, three different types of deflection methods (split angle, total internal reflection, Wollaston prism) are described. Design, construction details and performance of three deflector models are reported. Combined deflection systems use the advantageous properties of each of these methods to economically obtain the maximum number of resolvable deflection positions. A suggested combination to achieve 1024 × 1024 positions arranged in a two-dimensional field would consist of one total internal reflection stage, seven stages of split angles, and two stages of Wollaston prisms for each dimension.     

灯泵浦Cr~(3 ):LiCaAlF晶体可调谐Q开关激光器

报道了闪光灯泵浦掺铬氟化铝钙锂（ＣｒＬｉＣＡＦ）可调谐、Ｑ开关激光器的实验结果。调谐范围为７３０～８５０ｎｍ，峰值波长为７８０ｎｍ。激光最大输出能量为１．６２Ｊ，斜率效率为０．８％，阈值为５０．４Ｊ。ＫＤ＊Ｐ晶体电光调Ｑ，单脉冲半宽度为４８ｎｓ，峰值功率为１．３×１０６Ｗ。     

输出5 W的电光调Q Nd:YAG陶瓷激光器

研究了激光二极管(LD)侧向抽运的Nd:YAG陶瓷电光调Q激光器的激光输出特性.该激光器采用九组激光二极管线阵列(LDA)侧面紧密环绕均匀排布的抽运结构,并用微通道热汇冷却技术冷却.在电光调Q方式下,重复频率为100 Hz,抽运单脉冲能量为416 mJ时,用尺寸为φ5 mm×75 mm,掺杂原子数分数为1%的Nd:YAG陶瓷棒,获得50 mJ的1064 nm激光输出,脉冲宽度为12 ns,斜率效率达24%.并实验测量和分析了偏振片,KD*P晶体,四分之一波片等调Q器件的插入损耗.测量了输出激光时间波形和光斑的光强空间分布.     

大功率线阵激光二极管侧面抽运Nd:YAG激光器特性研究

对激光二极管（LD）抽运固体激光器中大功率线阵激光二极管三向对称侧面抽运的漫反射腔结构进行了研究。激光器使用Nd：YAG作为激光晶体，电光器件材料为KD^＊P晶体，漫反射体为陶瓷材料。实验表明，抽运光的利用率和均匀性有较大提高。在重复频率为10Hz下，实现了脉冲宽度8ns，最大平均功率为近2W的1064nm红外激光输出，激光器的效率有显著提高。     

1319nm Nd:YAG脉冲电光调Q激光器的研究

为了研究脉冲输出波长为1319nm的Nd:YAG激光器,通过分析Nd:YAG激光介质的辐射跃迁能级,采用镀制高选择性介质膜的方法抑制1064nm等其它波长的起振,最终实现1319nm激光单脉冲输出。实验中采用闪光灯抽运、水冷Nd:YAG激光器,KD*P调Q,平平腔结构,获得1319nm激光静态输出能量340.9mJ,动态输出76.8mJ,重频1Hz,脉宽17ns,束散角2.7mrad。结果表明,通过镀制高选择性介质膜的方法可以实现1319nm激光调Q脉冲输出。     

High average power harmonic generation

High average power frequency conversion using solid-state nonlinear materials is discussed. Recent laboratory experience and new developments in design concepts show that current technology, a few tens of watts, may be extended by several orders of magnitude. For example, using KD*P, efficient doubling (> 70 percent) of Nd:YAG at average powers approaching 100 KW is possible; for doubling to the blue or UV regions the average power may approach 1 MW. Configurations using segmented apertures permit essentially unlimited scaling of average power. High average power is achieved by configuring the nonlinear material as a set of thin plates with a large ratio of surface area to volume, and cooling the exposed surfaces with a flowing gas. The design and material fabrication of such a harmonic generator is well within current technology.     

Design and simulation of waveguide electrooptic beam deflectors

Numerical simulation based on the scalar beam propagation method, was used to investigate the performance of waveguide electrooptic beam deflectors. The deflectors under investigation consist of a stack of electrooptically controlled prisms in a waveguide. The results were compared to earlier simplified analysis. It was found that for given overall device dimensions, the number of interfaces between prisms in a prism-type electrooptic deflector has significant influence on the device performance when it is small. To avoid wavefront distortion, unwanted reflection from the interfaces, and asymmetry in the deflection angles caused by small number of interfaces, one should use more than about ten interfaces in a typical deflector. Additional insights of device operation and design issues are discussed     

1.57μm内腔光学参量振荡器研究

对内腔光学参量振荡器的工作机理进行了简要分析 ,报道了一种高效、紧凑的 1.5 7μm人眼安全内腔光学参量振荡器的实验结果。它的泵浦源为水冷闪光灯泵浦KD P电光调Q (Ce ,Nd) :YAG激光器 ,采用KTPⅡ类非临界相位匹配 ,输出信号光脉冲能量最高达 87.7mJ ,脉宽约7ns ,重复频率为 10Hz ,总电光效率最高达 5 .8‰ ,器件外形尺寸为 4 10mm× 130mm× 80mm。