Stimulated rotational Raman conversion in H2, D2, and HD

Stimulated rotational Raman conversion has been efficiently demonstrated in all three molecular hydrogen isotopes with a 532-nm Q-switched pump source. Optimum gas pressures and pump focusing have been determined. Single pass conversion efficiencies of 80%, 75%, and 65% have been achieved at the first Stokes wavelengths with H₂ , D₂, and HD, respectively. The maximum efficiency is generally limited by further Raman conversion of the initially generated Stokes light. The thresholds were found to increase in the order H₂ 22. The relative thresholds of H₂ and D₂ are reasonably consistent with the calculated steady-state gains based on the population statistics and the linewidth data. Intermediate frequency shifts such as these may be useful by themselves, or in combination with other nonlinear techniques, as methods to achieve specific wavelengths for system applications     

Nd:YAG四倍频激光抽运D2和D2/He受激拉曼散射的实验研究

使用脉冲Nd:YAG四倍频激光抽运充有纯D2气体和D2/He混合气体的拉曼池.实验研究了受激拉曼散射的能量转换效率和能量稳定性与系统主要参量,包括抽运光能量、D2气体压强和加入惰性气体He的关系.实验表明,适量惰性气体He的加入在没有降低一阶斯托克斯散射光(S1,波长:289.04 nm)能量稳定性的前提下,有利于提高其能量转换效率,最大能量转换效率达到22.1%.通过实验分析,得到了受激拉曼散射一阶斯托克斯散射光的能量转化效率和能量稳定性的优化条件.     

Third harmonic generation of Nd:YAG laser light in periodicallypoled LiNbO3 waveguide

The authors propose and first demonstrate an LiNbO₃ waveguide device with cascading quasi-phase-matched second harmonic generation and quasi-phase-matched sum-frequency generation for generation of a third harmonic wave. Ultraviolet light of 355 nm wavelength, which was the shortest value ever reported for LiNbO₃ waveguide wavelength-convertors, was obtained with Nd:YAG laser light     

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.     

670 nm Nd:YAlO3/LBO腔内倍频激光器

报道了670nmNd:YAlO3/LBO腔内倍频激光器。通过计算分析光学谐振腔参数,设计了较佳的谐振腔参数,在抽运平均功率为1664W时获得了1.2W的670nm激光输出。     

Internally folded Nd:YAG and Nd:YVO4 lasers pumped bylaser diodes

An efficient, scalable, diode-pumped Nd laser design is reported. The gain element can be longitudinally pumped along five separate axes and is relatively simple to fabricate. Both Nd:YAG and Nd:YVO₄ gain media were evaluated. Using five single-stripe laser diodes to pump the Nd:YAG, 3.94 W of absorbed power produced 2.1 W CW at 1.06 μm. The slope efficiency was 54 percent and the output was TEM₀₀. The threshold power was 40 mW. No evidence of thermal saturation was observed up to the maximum pump power. Repetitively Q-switched operation is also reported. The maximum output power for Nd:YVO₄ obtained with 2.9 W of pump power was 1.3 W. The slope efficiency was 47 percent     

Nd:YAG四倍频激光抽运氘后的拉曼效应及其在激光雷达中的应用

利用 Nd:YAG四倍频激光抽运氘气 (D2 )的受激拉曼效应 ,获得一阶斯托克斯 (Stokes)波长2 89nm。通过改变拉曼介质 D2 气压与抽运光能量 ,获得了一阶斯托克斯输出的较佳条件。该波长与 Xe Cl准分子激光波长 30 8nm采用差分吸收方法 ,建立了用于对流层臭氧探测的激光雷达 ,并初步获得了对流层大气臭氧的垂直分布及其时间变化特征。     

High power, CW single-frequency, TEM00,diode-laser-pumped Nd:YAG laser

255 mW of 1.06 μm, CW, single-longitudinal-mode, TEM₀₀ output has been obtained by end-pumping a twisted-mode cavity Nd:YAG laser with a 1 W diode laser. The key elements of the laser are two λ/4 waveplates (zero-order) placed at both ends of the laser crystal (Nd:YAG, φ3×8 mm). The fast axes of the waveplates are rotated by 90° with respect to each other and rotated by 45° with respect to an intercavity Brewster polariser. In addition, one of the waveplates acts as a resonator and mirror and input coupler for the pump radiation     

高功率BNN倍频连续YAG激光器

以铌酸钡钠置于Nd:YAG腔内,采用温度匹配,进行了连续倍频激光的研究,获得0.53微米输出功率达瓦级水平,最高可达2.5瓦以上。     

LD泵铺Nd：YVO4／Cr：YAG被动调Q绿光激光器

报道了一种LD近贴泵浦、KTP晶体腔内倍频的Nd:YVO4/Cr:YAG结构高重复频率被动调Q绿光激光器。在注入泵浦功率为750mW时,得到平均功率86mW、脉冲宽度26.6ns、重复频率79.2kHz、峰值功率41.1W的被动调Q脉冲绿光输出。     

稳定腔偏振抽取单横模Nd:YAG激光器

将振荡与放大光束分离,使其分别抽取工作物质不同部位的贮能,可以获得较高功率和效率,也降低了对工作物质光学均匀性的要求。     

End-pumped Nd:LaF3 and Nd:LaMgAl11O19 lasers

Nd:LaF₃ and Nd:LaMgAl₁₁O₁₉ (LMA) are promising candidates for pulsed diode-laser-pumped lasers because they have relatively long upper state lifetimes and large absorption bandwidths compared to other Nd³⁺ doped materials. Crystal growth of LMA and the spectroscopic properties of both materials are described. Continuous-wave (CW) end-pumped lasers have been demonstrated in these materials using a Ti:Al₂O₃ laser to simulate the diode-laser pump source. Slope efficiencies of 47% for Nd:LaF₃ and 32% for Nd:LMA were obtained. The results for Nd:LaF₃ are typical for end-pumped, CW, Nd³⁺ lasers; the lower slope efficiency for Nd:LMA is attributed to excited-state absorption     

Reliability of a connected-(r1, s1)-or-(r2, s2)-or-..-or-(rk, sk)-out-of-(m,n): F lattice system

A (linear or circular) connected-(r₁, s₁)-or-(r₂, s₂)-or-^{. .}-or-(r_k, s_k)-out-of-(m, n): F lattice system is the (linear or circular) (m, n)-lattice system if the system fails whenever all components in a connected-(r₁, s₁)-submatrix or all components in a connected-(r₂, s₂)-submatrix or ^{. .} or all components in a connected-(r_k, s_k)-submatrix fail. This paper presents a recursive algorithm for the reliability of the (linear or circular) connected-(r₁, s₁)-or-(r₂, s₂)or-^{. .}-or-(r_k,s_k)-out- of-(m, n):F lattice system. The recursive algorithm requires time and time in the linear case and the circular case, respectively Furthermore, we can reduce the more computing time in the statistically independent and identically distributed case or considering some special systems. Especially, the closed formula is given for the reliability of the linear connected-(2, 1)-or-(1, 2)-out-of-(m, 2): F lattice system in the statistically independent and identically distributed case.     

长脉冲非偏振准分子激光在H_2中的受激喇曼散射

实验研究了X射线预电离XeCl准分子激光器在氢气中的受激喇曼散射。用光电管观察到S_1、S_2和S_3斯托克斯线输出。对受激喇曼散射导致光束发散角减小和脉宽变窄进行了理论分析。     

角隅谐振腔SBS Q开关Nd:YAG激光器

用受激布里渊散射（SBS）作Q开关，用角隅棱镜和普通反射镜一起构成位相共轭谐振腔，获得输出能量＞50mJ、脉冲宽度15ns、在重复频率1～25pps的范围内具有小的光束发散角的稳定脉冲输出。     

单纵模Nd:YAG激光抽运H2-He混合气体中的强后向受激拉曼散射

用单纵模Nd：YAG二倍频激光（波长532nm，线宽0．003cm^-1，脉宽（半峰全宽，FWHM）6．5ns）抽运Hz／He气体，观察到很强的后向一阶斯托克斯（BS1）受激拉曼散射。在Hz的分压分别为1．0MPa和1．5MPa的Hz／He（体积比）（3／7）混合气体中，当抽运能量为92mJ时，后向一阶斯托克斯光的量子转换效率高达69％左右，而在纯Hz中后向一阶斯托克斯光的量子转换效率分别只有15％和18％。这是因为加入He增强了后向拉曼散射多普勒线宽的Dicke压窄效应，使后向一阶斯托克斯光的拉曼增益系数与前向一阶斯托克斯（FS1）光的拉曼增益系数的比率提高，而且因为后向一阶斯托克斯光与抽运光在反方向传播，它可以提取大部分抽运光的能量，并且脉冲被压窄到1．1ns，使后向一阶斯托克斯光峰值功率达到了抽运光的2．6倍。从激光光斑的强度分布可以观察到后向一阶斯托克斯光呈现为抽运光的相位共轭波。     

连续Nd:YAG激光器中Cr~(4 ):YAG被动调Q的稳定性和功率的提高

Ｃｒ４＋ＹＡＧ用于连续ＮｄＹＡＧ激光器被动调Ｑ，激光横模结构和纵模结构以及激光泵浦速率起伏等是引起调Ｑ不稳定的重要因素，运用一定的技术可以使调Ｑ稳定性得到根本性改善；此外应考虑Ｃｒ４＋ＹＡＧ热效应及光学薄膜的激光损伤     

LD抽运的Cr4+:YAG被动调Q Nd:YAG激光器

研究了不同谐振腔下不同透射率的Cr4+:YAG调Q的激光输出特性.采用透射率为82%的Cr4+:YAG,在抽运功率1.1 W时,激光重复频率小于3 kHz,单脉冲能量达20 μJ,可以作为微脉冲激光雷达的发射光源.分析和比较了实验结果和理论计算,两者吻合较好.     

Raman Scattering and Nd3+ Laser Operation in NaLa(WO 4)2

The continuous-wave laser operation of Nd-doped tetragonal NaLa(WO ₄)₂ crystal is studied at room temperature by optical pumping in the spectral region overlapping AlGaAs diode laser emission. This crystal has inhomogeneously broadened optical bands. From the room-temperature spectroscopic parameters determined it is found that the optimum Nd concentration for the ⁴F_3/2rarr⁴I_J laser channels must be in the 3-5 at.% range. For J=11/2 and 13/2 channels (lambdaap1.06 and 1.3 mum) the most favourable polarization configuration is parallel to the crystallographic c axis, while for J=9/2 little polarization dependence of the laser efficiency is predicted. Laser operation was achieved with a 3.35 at.% Nd-doped sample grown by the Czochralski method. The laser operation was tested in an hemispherical optical cavity pumped by a Ti:sapphire laser. Stimulated emission at lambda=1056 nm was achieved for a wide spectral pumping range, lambda=790-820 nm. Stimulated Raman scattering was achieved in the picosecond regime with an efficiency similar to that of monoclinic KY(WO₄)₂ reference compound     

CW Nd: YAG激光器中Cr~(4 ): YAG被动调Q的实验研究

对Ｃｒ４＋ＹＡＧ被动调ＱＣＷＮｄＹＡＧ激光器的重复频率和脉冲宽度与输出功率的关系作了系统的实验研究。用Ｃｒ４＋ＹＡＧ作为可饱和吸收体在ＣＷＮｄＹＡＧ激光器中获得了重复频率为２．２～１０ｋＨｚ，脉宽为１２０～９００ｎｓ的稳定的调Ｑ序列脉冲输出。不同初始透过率的Ｃｒ４＋ＹＡＧＱ开关对应不同范围的重复频率和脉宽。观察到了调Ｑ脉冲包络中的调制现象并给出了合理的解释。