A 7-W diode-pumped Nd:YVO4 cw laser at 1.34 μm

A Nd:YVO₄ laser, end-pumped by a fiber-coupled diode-laser array, generates 7.3 W of output power at 1342 nm, the highest so far reported for this host crystal. The slope efficiency is 40% and the output-beam divergence is close to the diffraction limit. An important point in attaining such results is the choice of crystals with low Nd concentration. Received: 16 July 2002 / Published online: 25 October 2002 RID="*" ID="*"Corresponding author. Fax: +39-050/844333, E-mail: dilieto@df.unipi.it RID="**" ID="**"Permanent address: Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, Italy     

YVO4/Nd:YVO4/YVO4 self-Raman laser at 1,764 nm

A diode-end-pumped composite YVO₄/Nd:YVO₄/YVO₄ crystal self-Raman laser at the second-Stokes wavelength of 1,764 nm is demonstrated. The maximum average output power of second-Stokes radiation was up to 0.99 W at a pump power of 34 W and a pulse repetition frequency of 20 kHz, corresponding to an optical conversion efficiency of 2.9 %. The highest peak power and the shortest pulse duration were 21.5 kW and 1.92 ns, respectively.     

Second Stokes 1129 nm generation in gray-trace resistance KTP intracavity driven by a diode-pumped Q-switched Nd:YVO4 laser

A gray-trace resistance KTP (GTR-KTP) second Stokes Raman laser intracavity driven by a diode-pumped acousto-optic Q-switched Nd:YVO₄ laser was first demonstrated in this paper. With an incident pump power of 9.5 W, the intracavity GTR-KTP Raman laser, operating at the repetition rate of 20 kHz, produced the maximum average output power of 860 mW at 1129 nm. The minimum pulse width obtained in this GTR-KTP Raman laser was 10.8 ns. When the GTR-KTP was substituted with a common KTP, a lower average output power of 720 mW and longer pulse width of 15.9 ns were obtained in the common KTP Raman laser under the same pump condition and cavity setup as the GTR-KTP Raman laser. Experimental results indicated that the decreased absorption at the fundamental and Stokes wave in GTR-KTP was beneficial to improve the stimulated Raman scattering performance.     

Q-switched mode-locked diode-pumped Nd:YVO_4 laser with a saturable Bragg reflector

We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of -230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of -150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.     

激光二极管泵浦Nd:YVO4/YVO4复合晶体绿光激光器

采用一种新型的Nd:YVO4/YVO4复合晶体,利用V型折叠腔,研究了高功率激光二极管端面泵浦的Nd:YVO4/YVO4复合晶体激光器基频1.06 μm及倍频532 nm激光的输出特性.当泵浦功率为24.6 W时,获得1.06 μm激光的最大输出功率为11.7 W,光-光转换效率为48%.当泵浦功率为17 W时,获得了5.32 W的绿光输出,光-光转换效率达到31.3%.     

Compact high-power mode-locked Nd：YVO4 picosecond laser using multiple-pass cavity

A stable self-starting mode-locked Nd:YVO4 laser with a Herriott-type multiple-pass cavity(MPC) operating at 1 064 nm is demonstrated.An in-band 880-nm laser diode is used as an end-pump and a semiconductor saturable absorber mirror(SESAM) is used for passive mode locking(ML) and providing pulse durations of 14 ps.At a pump power of 26.4 W,the maximum average output power is as high as 10.5 W at a repetition rate of 22 MHz,which corresponds to a single pulse energy of 0.48 μJ.Optical-tooptical conversion efficiency is as high as 39.8% at the maximum output power with a slope efficiency of 55.2%.     

Output properties of diode-pumped passively Q-switched 1.06 μm Nd:GdVO4 laser using a [100]-cut Cr4+:YAG crystal

A passively Q-switched 1.06???m Nd:GdVO₄ laser with a [100]-cut Cr⁴⁺:YAG saturable absorber was demonstrated. The output characteristics were investigated when the anisotropic transmission of Cr⁴⁺:YAG crystal and the incident pump power level were considered. The experimental results showed that it was feasible to generate laser with narrower pulse width (?? _p ), higher pulse energy and peak power when the polarization direction of laser was parallel to the [001], [010], [ $00\overline{1}$ ], and [ $0\overline{1}0$ ] orientations of the Cr⁴⁺:YAG crystal. The different changes of ?? _p as a function of incident pump power was observed due to the anisotropy of transmission of Cr⁴⁺:YAG and the different gain levels (pump power levels). If the Cr⁴⁺:YAG was fully bleached as a result of high cavity gain or due to the laser polarization direction was parallel to the [001], [010], [ $00\overline{1}$ ], and [ $0\overline{1}0$ ] orientations, ?? _p was constant, otherwise ?? _p decreased when the gain increased.     

BBO四倍频全固态Nd:YVO4紫外激光器

报道了用BBO晶体对激光二极管抽运Nd:YVO4晶体声光调Q产生的1.064μm激光进行四倍频,实现平均功率为63mW准连续波266nm紫外激光运转,重复频率为12.5kHz、单脉冲能量5μJ、峰值功率达252W,绿光-紫外光转换效率达11%.     

高效率多程折叠Nd:YVO4激光放大器

采用具有近共焦、非稳腔特点的多程折叠光路结构,使激光光束多次通过增益介质,实现了高提取效率的激光放大器.实验中在注入22W种子激光的条件下,以43.9%的提取效率得到了63 W的激光输出,斜效率超过52%,激光放大器的输出光束质量从种子激光的M2X=2.08,M2Y=1.92变为M2X=2.84,M2Y=1.79.     

激光二极管泵浦Nd∶YVO4/YVO4复合晶体绿光激光器

采用一种新型的Nd∶YVO4/YVO4复合晶体,利用V型折叠腔,研究了高功率激光二极管端面泵浦的Nd∶YVO4/YVO4复合晶体激光器基频1.06 μm及倍频532 nm激光的输出特性.当泵浦功率为24.6 W时,获得1.06 pm激光的最大输出功率为11.7 W,光-光转换效率为48%.当泵浦功率为17 W时,获得了5.32 W的绿光输出,光-光转换效率达到31.3%.     

LD连续泵浦Nd:YVO4声光调Q激光器

利用半导体激光器（LD）连续单端泵浦Nd:YVO4晶体,实现了声光调Q输出1 064nm的短脉冲。分析并用实验验证了不同透过率输出耦合镜及不同重复频率条件下,输出调Q脉冲能量、脉冲宽度及平均输出功率的规律。在泵浦功率为20.7W,重复频率为50kHz时,获得了最大平均输出功率为5.72W的脉冲,光 光转换效率为28%,斜效率为32.4%;在重复频率为10kHz时,最大单脉冲能量为0.286mJ,脉宽为22ns,峰值功率为13kW。     

激光二极管端面抽运Nd:YVO4板条激光器及其热效应

激光器中激光介质采用板条状几何结构可以极大地降低它的热效应,但仍然需要进一步分析其影响,进而优化激光器效率.利用有限元分析方法分析了部分端面抽运的混合腔板条激光器中激光介质的热效应,计算的热透镜焦距与实测结果基本相符.分析了热效应对模式匹配的影响,分析结果对于优化激光器效率、改进谐振腔设计具有一定的参考价值.并在分析的基础上进行了混合腔实验,抽运功率为110 W时,获得连续输出激光功率41.5 W,光光转换效率约38%,斜效率达58.8%,M2因子为非稳腔方向M2x＝1.59,稳定腔方向M2y＝1.55.     

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     

激光二极管抽运Nd:YVO4晶体的三维热效应分析

针对激光二极管抽运的以Nd:YVO4板条晶体为增益介质的激光器件,基于有限容积法数值分析各向异性介质的热传导方程,给出了Nd:YVO4晶体板条结构的热分布数值模型,并分别模拟仿真了808nm半导体激光器双端端面抽运,大面均匀抽运,大面周期分布抽运三种抽运结构,得到了Nd:YVO4板条晶体在这三种抽运结构下的非稳态时不同时刻的温度曲线和稳态时的三维温度分布切面图.     

LD连续泵浦Nd:YVO4声光调Q激光器

 利用半导体激光器（LD）连续单端泵浦Nd:YVO₄晶体，实现了声光调Q输出1 064nm的短脉冲。分析并用实验验证了不同透过率输出耦合镜及不同重复频率条件下，输出调Q脉冲能量、脉冲宽度及平均输出功率的规律。在泵浦功率为20.7W，重复频率为50kHz时，获得了最大平均输出功率为5.72W的脉冲，光 光转换效率为28%，斜效率为32.4%；在重复频率为10kHz时，最大单脉冲能量为0.286mJ，脉宽为22ns，峰值功率为13kW。     

激光二极管泵浦的高效、单频Nd:YVO4激光器

对激光二极管端面泵浦的单频Nd:YVO4激光器进行了研究,研究了不同输出耦合率情况下输出功率随泵浦功率的变化曲线及光-光转化效率随输出耦合率的变化曲线,实验结果与理论分析结果基本一致.当泵浦功率为2.2 W时,得到瓦级单频1064 nm激光输出,最高光-光转化效率为47.2%.     

Single-frequency operation of a diode-pumped green laser using multi-Brewster plates

In a diode-pumped, KTP intracavity frequency-doubled green laser, multi-Brewster plates are used to achieve high power single-frequency operation. With a simple experimental setup, single-frequency operation of the diode-pumped green laser with output of 46 and 218 mW is obtained by one and three Brewster plate, respectively.     

单频运转的Nd：YVO4激光器

报道了激光二极管纵向泵浦单频运转的Ｎｄ：ＹＶＯ４激光器，用波长为８０９ｎｍ激光二极管的连续输出功率６６０ｍＷ泵浦，获得１０６４ｎｍ，功率为１５５ｍＷ连续单频输出，泵浦阈值２２６ｍＷ，斜率效率３３．８％，线宽小于１０ＭＨｚ．     

Generation of UV radiation at 335.5 nm based on frequency-quadrupling of a diode-pumped Nd:YVO_4 laser

The generation of ultraviolet(UV)light at 335.5 nm based on frequency quadrupling of a diode-end- pumped Q-switched Nd:YVO_4 laser at 1342 nm was demonstrated.KTP crystal was used for generation of wavelength of 671 nm by intracavity doubling and LBO(BBO)crystal was exploited for the subsequent external fourth harmonic generation(FHG).With 6.3-W absorbed pump power and 10-kHz frequency repetition rate,the UV output power of 35 and 63 mW were obtained by using LBO and BBO as frequency quadrupling nonlinear crystals,respectively.The experimental results show that the conversion efficiency (red-UV)of 6.4% for BBO crystal is higher than that of 3.5% for LBO crystal,but the UV beam quality obtained by LBO crystal is better than by BBO crystal.