被动调Q自拉曼Nd∶GdVO4激光器

对激光二极管(LD)抽运的自拉曼Nd∶GdVO4被动调Q激光器进行了详细的理论和实验研究。实验中采用Nd∶GdVO4晶体同时作为激光介质和拉曼晶体,分别用了两块不同初始透射率的Cr4 ∶YAG晶体,得到并比较了采用不同初始透射率的Cr4 ∶YAG晶体时被动调Q自拉曼激光器的性能。测量了平均输出功率、脉冲宽度和脉冲重复率随抽运功率的变化关系。当Cr4 ∶YAG的初始透射率为0.91,输入功率是5.7 W时,得到的拉曼光的最高功率为244.6 mW,相应的转换效率为4.3%。通过数值求解基频光和拉曼光空间分布的速率方程并应用到被动调Q自拉曼Nd∶GdVO4激光器。获得的理论结果与实验结果大致相符。     

被动调Q自拉曼Nd:GdVO4激光器

对激光二极管(LD)抽运的自拉曼Nd:GdVO4被动调Q激光器进行了详细的理论和实验研究.实验中采用Nd:GdVO4晶体同时作为激光介质和拉曼晶体,分别用了两块不同初始透射率的Cr4 :YAG晶体,得到并比较了采用不同初始透射率的Cr4 :YAG晶体时被动调Q自拉曼激光器的性能.测量了平均输出功率、脉冲宽度和脉冲重复率随抽运功率的变化关系.当Cr4 :YAG的初始透射率为0.91,输入功率是5.7 W时,得到的拉曼光的最高功率为244.6 mW,相应的转换效率为4.3%.通过数值求解基频光和拉曼光空间分布的速率方程并应用到被动调Q自拉曼Nd:GdYO4激光器.获得的理论结果与实验结果大致相符.     

LD泵浦Nd∶GdVO4晶体Cr4+∶YAG被动调Q激光特性研究

考虑腔内光子数密度的空间高斯分布以及晶体热效应的影响,给出了LD泵浦Nd∶GdVO4晶体Cr4+∶YAG被动调Q 1.06 μm激光的耦合速率方程组.数值求解该方程组获得了输出激光的脉冲宽度、重复率、峰值功率以及单脉冲能量随泵浦功率的变化特性,其理论值与实验结果相符.     

新型激光晶体Nd：GdVO_4

报导了新型激光晶体Nd:GdVO4的结构及生长;研究了其光谱特性,得出在808 nm处具有较强的吸收峰,且三个主发射峰波长分别为912.6 nm、1 063.1 nm、1 341.3 nm;讨论了其热导率,认为具有很高的热导率可能是因为掺入Nd3 后晶格畸变并不大引起的;通过与Nd:YVO4和Nd:YAG进行性能比较,证明该晶体是LD泵浦高功率激光器的理想工作物质.     

不同泵浦光下Nd∶GdVO_4晶体输出特性

为研究808nm和879nm两种泵浦光对Nd∶GdVO4晶体激光输出特性的影响,并比较两种不同波长泵浦所得连续输出光的效率高低,分析了Nd∶GdVO4晶体的能级结构和两种泵浦光作用下的激光输出特性,发现在879nm也有较强的吸收峰.用808nm和879nm两种不同波长泵浦Nd∶GdVO4晶体的过程是不同的,808nm泵浦是一种间接方式能量转移的过程,在此过程中有明显的热负载产生.而879nm泵浦是将粒子直接激励到激光辐射上能级,降低无辐射弛豫过程产生的热量.从理论上可知,879nm的泵浦量子效率要高于808nm的泵浦量子效率,对减少晶体的热产生有很强的优势.实验中采用激光二极管端面泵浦Nd∶GdVO4晶体直腔方案,研究了两种不同泵浦光泵浦Nd∶GdVO4晶体以获得1063nm的连续光,得到了两种光抽运时的斜效率,发现在同样实验条件下,879nm泵浦的输出光斜效率在小功率泵浦时略高于808nm;而在大功率泵浦的情况下明显高于808nm,最高达到38%.同时,在808nm抽运时,实验上获得了1341nm波长的激光,为光通讯的应用提供了一种光源.     

新型激光晶体Nd：GdVO4

报导了新型激光晶体Nd：GdVO4的结构及生长；研究了其光谱特性，得出在808nm处具有较强的吸收峰，且三个主发射峰波长分别为912．6nm、1063．1nm、1341．3nm；讨论了其热导率，认为具有很高的热导率可能是因为掺入Nd^3＋后晶格畸变并不大引起的；通过与Nd：YVO4和Nd：YAG进行性能比较，证明该晶体是LD泵浦高功率激光器的理想工作物质．     

LD侧面泵浦Nd:GdVO4 532 nm绿光激光器

为了获得高功率窄脉宽532 nm绿光激光输出,通过高重复频率声光驱动调Q技术和LD侧面泵浦Nd∶GdVO4技术,获得高功率线偏振1 064 nm激光输出.采用内腔倍频方式,对非线性晶体KTP进行频率变换,实现高功率窄脉宽绿光激光输出.在电源输入电流30 A,调Q驱动频率10 kHz的条件下,获得最高功率30 W线偏振1 064 nm激光输出,脉宽30 ns,倍频KTP晶体获得23.4 W的532 nm绿光输出,1 064 nm到532 nm转化效率为78％.实验结果表明:通过声光调Q技术和LD侧面泵浦Nd∶GdVO4技术,可以实现高功率线偏振窄脉宽1 064 nm激光输出,倍频非线性晶体KTP可获得高功率窄脉宽532 nm激光.     

LD泵浦的Nd∶GdVO_4/KTP腔内倍频激光器(英文)

基于对Nd∶GdVO4 晶体热焦距的测量及其 1.0 6 μm激光基本性能 ,用三镜折叠腔研究了半导体激光器 (LD)泵浦的Nd∶GdVO4 /KTP晶体的内腔倍频性质 当用从直径为 2 0 0 μm的单光纤输出的低功率的半导体激光泵浦时 ,绿光的阈值是 2 6mW ,光光转换效率为 17.3% 当用从直径为 1.5 5mm的光纤束输出的高功率的半导体激光泵浦时 ,绿光的阈值是 2 0 0mW ,光光转换效率为 19.35 %     

Nd∶NaR(WO_4)_2晶体生长(R=Bi,Y)

采用提拉法生长出了掺钕钨酸铋钠[Nd∶NaBi(WO4)2,简称Nd∶NBW]和掺钕钨酸钇钠[Nd∶NaY(WO4)2,简称Nd∶NYW]晶体,并给出了制备无开裂优质Nd∶NBW和Nd∶NYW晶体的最佳生长工艺参数。从XRD分析得到Nd∶NBW和Nd∶NYW晶体的晶胞参数,并分析了晶体的拉曼光谱,认为二者结构基本相同,为四方晶系、白钨矿结构、I41/a空间群。由吸收光谱可以看出,Nd∶NBW在802nm有较强的吸收峰,Nd∶NYW在804nm、752nm、586nm附近有较强、较宽的吸收峰,二者均适合于LD泵浦;计算了晶体中Nd3+的吸收截面积。     

1 342 nm激光泵浦光子晶体光纤受激喇曼散射的实验研究

利用调Q Nd∶GdVO4 激光器为泵浦源,对100 m非线性光子晶体光纤中受激拉曼散射谱的形成过程进行了实验研究.随着泵浦功率的增加,在中心~1 575 nm处得到一个宽带光谱,并观察到光谱内部出现能量红移现象,使得光谱能量从1 546 nm处转移到1 615 nm.     

不同激光分布下Nd∶GdVO4晶体热焦距分析

为了研究方形激光晶体Nd∶GdVO4在超高斯泵浦光分布下的热效应,采用半解析的分析方法,进行了理论分析和实验验证.结果表明：当使用输出功率为15 W的半导体激光器端面中心入射时,在抽运端面中心获得1.38 μm最大热形变量（超高斯阶次为2时）和220 mm的热焦距（超高斯阶次为5时）.     

Nd:YVO4激光晶体Raman光谱的分析

根据商群对称性分析法对Nd :YVO4 晶体的Raman光谱做了理论计算和指认 ,运用实验的手段 ,根据谱线数目判定其合理性 ,同时断定晶体原胞中含有 4个Nd :YVO4 分子     

Characteristics of the temperature-tunable Nd:YAG/YVO4 Raman laser

We demonstrate a tunable crystalline Raman laser by varying the temperature of Raman crystal. Nd:YAG and YVO(4) crystals were selected as the laser and Raman gain media, respectively. The center wavelength of this Nd:YAG/YVO(4) Raman laser was tuned over a 0.49 nm range from 1175.76 to 1175.27 nm when the temperature of the Raman crystal was adjusted from 5 °C to 150 °C. The characteristics of this Raman laser including tunability, output power, and beam quality factors (M(2)) dependent on temperature were also studied in this paper.     

All-solid-state 704 mW continuous-wave yellow source based on an intracavity, frequency-doubled crystalline Raman laser

Continuous-wave operation at 588 nm of a diode-pumped Nd:GdVO4 laser with intracavity Raman shifting [in KGd(WO4)2, KGW] and frequency-doubling (in LiB3O5, LBO) is reported. A maximum cw power at 588 nm of 704 mW was obtained for diode pump powers of 13.7 W. Quasi-cw yellow powers up to 1.57 W at a 50% duty cycle (to reduce thermal load in the laser crystal) indicate that power scaling to over 1 W is feasible.     

Radiation Hardness of Nd:GdVO4 Laser Crystal under γ-Ray Irradiation

Physics of Wave Phenomena - The radiation hardness of neodymium-doped gadolinium vanadate crystal (Nd:GdVO4) has been investigated. Crystal with sizes of 4×4×8 mm doped to a level of 0.5%...     

Study on optical characteristics of Nd:YVO4/YVO4 composite crystal laser

Thermal effect in crystals is the main obstacle blocking diode-pumped solid state laser to get high and stable output power. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lensing theoretically based on the numerical heat analysis to the end-pumped anisotropic laser crystal. The temperature distributions in Nd:YVO4/YVO4 composite crystal and conventional crystal were analyzed and compared. The end-pumped Nd:YVO4/YVO4 composite crystal laser was designed and set up with z-cavity. The maximum output powers of 9.87 W at 1064 nm and 6.14 W at 532 nm were obtained at the incident pump power of 16.5 W. The highest optical-optical conversion efficiencies were up to 59.8% at 1064 nm and 37.2% at 532 nm respectively.     

Second-Stokes YVO4/Nd:YVO4/YVO4 self-frequency Raman laser

We demonstrated an efficient second-Stokes Raman laser emission at 1313 nm based on self-frequency stimulated Raman scattering from a diode-end-pumped actively Q-switched YVO(4)/Nd:YVO(4)/YVO(4) laser at 1064 nm for the first time, to the authors' knowledge. A double-end diffusion-bonded Nd:YVO(4) composite crystal was adopted for sufficiently improving the thermal lensing effect in the course of self-frequency stimulated Raman scattering operation. With an incident pump power of 14.6 W and a pulse repetition (PRR) of 40 kHz, a maximum average output power of 2.34 W was obtained, corresponding to an optical-to-optical conversion efficiency of 16%. Pulse width and peak power were 1.2 ns and 49 kW, respectively.     

Efficient laser performance of Nd:GdVO4 crystals grown by the floating zone method

Efficient laser performance is demonstrated with Nd:GdVO4 crystals grown by the floating zone method. With a 2-at. % Nd-doped crystal a slope efficiency of 67% is achieved with pumping at 808 nm. We also find that pumping at 879 nm with a bandwidth of 1.8 nm is practical for laser diode pumping. With this pumping level the slope efficiency reaches 78%. High-quality Nd:GdVO4 crystals are successfully grown with as much as 15-at.% Nd concentration by the floating zone method without inclusions or macroscopic defects. Homogeneity and high reproducibility of crystal growth are confirmed.     

第三类热边界条件对激光晶体热效应的影响

以各向异性半解析热分析理论为基础,研究矩形横截面Nd∶YVO4激光晶体在有第三类热边界条件工作时,激光晶体温度场分布和晶体抽运面热形变分布.通过激光晶体工作特点分析,建立符合激光晶体工作状态的热模型.利用各向异性介质热传导方程的半解析求解方法,得出了矩形截面Nd∶YVO4晶体的温度场、端面热形变场的通解表达式.研究结果表明：当使用输出功率为15 W半导体激光器端面中心入射Nd∶YVO4晶体（晶体掺钕离子质量分数为0.5%）时,在抽运端面中心获得499.5 K最高温度和0.99 μm最大热形变量.和将第三类热边界条件近似为第二类热边界条件的通用做法相比更准确.这种方法可以应用到其它激光晶体热问题研究中,为有效解决激光系统热问题提供了理论依据.