High average power Q-switched green beam generation by intracavity frequency doubling of diode-side-pumped Nd:YAG/HGTR-KTP laser

To obtain high power and high beam quality second harmonic generation, a Q-switched system has been demonstrated by intracavity frequency doubling of two diode-side-pumped Nd:YAG modules with double AO-modulators in an astigmatism compensated cavity geometry. A maximum average frequency doubled power of 185 W is obtained when the pumping power is 600 W for each module. The corresponding optical-to-optical conversion efficiency is 15.4% and the pulse width is 180 ns at a repetition rate of 10 kHz. An instability of 2.5% was measured over a period of 2 h and the beam quality factors were measured to be , the maximum output power.     

Efficient and high-power intracavity frequency doubled diode-side-pumped Nd:YAG/KTP continuous wave (CW) green laser

Highly efficient continuous wave (CW) green beam generation by intracavity frequency doubling of a diode side-pumped Nd:YAG laser using a single pump head based on a copper-coated flow tube in a V-shaped cavity geometry has been demonstrated. A maximum 30.5 W of CW green power was obtained at a total diode pumping power of 260 W corresponding to 11.7% conversion efficiency of diode pump power to CW green power and 4.7% conversion efficiency of electrical power to CW green power. The performance of the laser by considering the pump power induced thermal lensing effect and the M²-parameter at the fundamental wavelength has been analyzed.     

36 W侧面抽运腔内倍频Nd:YAG/KTP连续绿光激光器

通过优化平-凹-平三镜折叠腔结构设计,利用大功率半导体激光器侧面抽运、Ⅱ类相位匹配KTP晶体腔内倍频,获得高效高功率连续绿色激光输出.当抽运电流约为36 A时,得到最高36.6 W的连续绿光激光输出,对应的光—光转换效率为8.71％.在输出功率33 W时测量激光功率稳定性,其功率不稳定度为0.27%.用刀口法测量了激光器高输出功率时的光束质量,光束质量因子小于8.对高功率抽运情况下三镜折叠腔的像散补偿、失调灵敏度和基模在腔内分布情况做了数值模拟. 关键词： 侧面抽运 腔内倍频 连续波     

LD抽运Nd：YAG／KTP腔内倍频连续绿光激光器实验研究

设计了LD端面抽运固体激光器平台,研究了LD抽运Nd:YAG/KTP腔内倍频连续绿光的输出特性、光-光转换效率、输出功率稳定性,并实验验证了倾斜反射镜的选模效果.该系统实现了基横模绿光输出,椭圆度达0.96.     

High-power high-stability Q-switched green laser with intracavity frequency doubling of diode-pumped composite ceramic Nd:YAG laser

We successfully obtain high-average-power high-stability Q-switched green laser based on diode-side-pumped composite ceramic Nd:YAG in a straight plano-concave cavity. The temperature distribution in composite ceramic Nd:YAG crystal is numerically analyzed and compared with that of conventional Nd:YAG crystal. By use of a composite ceramic Nd:YAG rod and a type-II high gray track resistance KTP (HGTR-KTP) crystal, a green laser with an average output power of 165 W is obtained at a repetition rate of 25 kHz, with a diode-to-green optical conversion of 14.68%, and a pulse width of 162 ns. To the best of our knowledge, both the output power and optical-to-optical efficiency are the highest values for green laser systems with intracavity frequency doubling of this novel composite ceramic Nd:YAG laser to date. The power fluctuation at around 160 W is lower than 0.3% in 2.5 hours.     

High power and high beam quality CW green beam generated by diode-side-pumped intracavity frequency doubled Nd:YAG laser

We report a stable high power and high beam quality diode-side-pumped CW green laser from intracavity frequency doubled Nd:YAG laser with LBO crystal. By using a advanced resonator, a large fundamental mode size in the laser crystal and a tight focus in the nonlinear crystal could be obtained simultaneously, which are favorable for high power and high beam quality CW green laser generation. The green laser delivered a maximum 532 nm output power of 40 W. The corresponding optical-to-optical conversion efficiency and electrical-to-optical conversion efficiency were 8.6% and 5.0%, respectively. Under 532 nm output power of 34 W, the beam quality factor was measured to be 1.6.     

LD抽运的Nd:YAG陶瓷/KTP绿光激光器

报道了一种LD端面抽运Nd:YAG陶瓷、KTP腔内倍频的全固态连续波绿光激光器.当抽运功率为21.6 W时,1064 nm基频输出达到11.3 W,光—光转换效率为52.3%.采用Ⅱ类切割的KTP晶体作为腔内倍频介质,在直腔结构下获得了最大功率为1.86 W的532　nm绿光输出,光—光转换效率为7%.输出光斑具有高斯型强度分布,1 W输出时的M²因子约为1.7. 关键词： 全固态绿光激光器 Nd:YAG陶瓷 KTP倍频 直腔     

激光二极管抽运Nd∶YVO4和KTP倍频产生单频绿光激发器

报道了一种激光二极管抽运、KTP倍频的Nd∶YVO4激光器,采用折叠腔,实现了稳定的高输出单频倍频运转,绿光输出功率达到102 mW,转换效率为10.7 %.     

Diode-pumped passively Q-switched intracavity frequency doubled Nd:GdVO4/KTP green laser

A compact diode-pumped passively Q-switched intracavity frequency-doubled Nd:GdVO₄/KTP green-pulse laser was demonstrated, using Cr⁴⁺:YAG as a saturable absorber in a simple flat–flat cavity. With a 5.9 W incident pump power, a passively Q-switched green laser was obtained with an average power of 397 mW, repetition rate of 40 kHz, and pulse width of 40 ns, when the initial transmission of Cr⁴⁺:YAG was 85%. The shortest pulse width of 30 ns, the highest green peak power of 696 W and the maximum pulse energy of 21 μJ were obtained when the initial transmission of Cr⁴⁺:YAG was 70%. Under CW green operation, we obtained 440 mW output power.     

93.7 W 1112 nm diode-side-pumped CW Nd:YAG laser

We demonstrate a high power continuous wave (CW) infrared laser operated at 1112 nm from a diode side-pumped Nd:YAG crystal with a plano-plano symmetrical resonator. By inserting an etalon, an output power of as high as 93.7 W at 1112 nm was obtained at the pump power of 570 W with conversion efficiency of 16.4%. The beam quality factor of M² was measured to be about 17. The wavelength tunable performance of the etalon was also analyzed. To the best of our knowledge, it is the highest output power at 1112 nm CW laser based on Nd:YAG crystal.     

LBO intracavity frequency doubled, Cr:YAG passively Q-switched Nd:YAG green laser

A LD-pumped, LBO intracavity frequency doubled and Cr:YAG passively Q-switched Nd:YAG green laser was reported in this letter. With 600 mW incident pump laser, Q-switched green laser with average power of 27 mW, pulse width of 15.2 ns, repetition rate of 16.4 kHz and peak power of 108.1 W was obtained.     

200 MHz CW mode-locked KTP intracavity frequency-doubled Nd:YAG laser

Experimental results of 200 MHz CW actively mode-locked KTP two-pass in-tracavity frequency-doubled Nd:YAG laser are reported.The primary factors influencingthe continuous-wave frequency-doubled conversion efficiency are analyzed.High efficiencylaser output was achieved by L-type folded-arm-cavity two-pass frequency-doubling.15 Waverage mode-locked power and 1.5W average mode-locked SHG green light output were ob-tained at 3.5kW single lamp input power respectively.     

60 W yellow laser at 561 nm by intracavity frequency doubling of a diode-pumped Q-switched Nd:YAG laser

A high-power yellow laser was achieved by intracavity frequency doubling of a diode-pumped Nd:YAG rod laser. A solid etalon was inserted into the resonator to implement efficient operation of the low-gain single line at 1123 nm transition. By using a LBO crystal inside the cavity as the frequency doubler, the maximum output power of the 561 nm yellow laser was obtained to be as high as 60.3 W with a pulse repetition frequency of 6 kHz, corresponding to an optical-to-optical conversion efficiency of about 6.1%. The output power fluctuation of the yellow laser was measured to be better than 3% in half an hour.     

二极管侧面抽运Nd:YAG/KTP腔内倍频百瓦级绿光激光器

为了获得百瓦级激光二极管侧面泵浦绿光激光器,设计了双棒串接、双声光调Q的Z型谐振腔结构.依据光束传输矩阵,通过软件模拟并计算了激光晶体内基模半径随屈光度的变化以及倍频晶体附近腔内光场在子午面和弧矢面内的分布情况,筛选出理想的谐振腔参数.在总泵浦功率1 080 W,声光调Q重复频率为10 kHz时,获得532 nm绿光最大平均输出功率为174.1 W,脉冲宽度为160 ns,光-光转换效率为16.1%,光束质量因子M2x＝9.63,M2y＝9.78.实验结果表明,使用双棒串接、双声光调制Z型腔结构,可以获得百瓦级高功率高光束质量532 nm绿光输出.     

3.8 W of cw blue light generated by intracavity frequency doubling of a 946-nm Nd:YAG laser with LBO

Efficient cw intracavity frequency doubling of a diode-end-pumped Nd:YAG laser operating on ⁴ F _3/2→⁴ I _9/2 transitions at 946 nm has been demonstrated. A symmetrical cavity with two composite laser rods was designed, which divides the pump power between the two composite laser rods, allowing for greater power scalability. A 30-mm-long LiB₃O₅ (LBO) crystal, cut for critical type I phase matching at 57 °C, was used for the intracavity frequency doubling of the laser. A maximum output power of 3.8 W in the blue spectral range at 473 nm has been achieved at 39 W of pump power. The beam quality M² value is 2.3 in both horizontal and vertical dimensions. PACS 42.55.Xi; 42.65.Ky     

Efficient generation of blue light by intracavity frequency doubling of a cw Nd:YAG laser with LBO

We report on the efficient room-temperature operation of ⁴F_3/2–⁴I_9/2 transition in a diode pumped Nd:YAG laser operating at 946 nm. An output power of 5.1 W and a slope efficiency of 23.6% at 946 nm have been obtained. Different LBO crystals of length 3×3×10 mm³, 3×3×15 mm³, 3×3×18 mm³ were selected as frequency doubling material for comparison. A maximum single-ended output power of 1.3 W at 473 nm was achieved by frequency doubling with an optical conversion efficiency of 5%. When the Nd:YAG rod was replaced by the one with high reflectivity coating at 473 nm on the pump side, the output power of blue light was almost twice that without high reflectivity coating for 473 nm at the same pump power level. Moreover, the theoretical optimum length of LBO crystal for intracavity frequency doubling was discussed, and the experimental results made a good agreement with it.     

Diode end-pumped Q-switched high-power intracavity frequency-doubled Nd:GdVO4/KTP green laser

A diode-laser-array end-pumped acousto-optically Q-switched intracavity frequency-doubled Nd:GdVO₄/KTP green laser, formed with a three-mirror folded resonator, has been demonstrated. With 15 W of pump power incident upon the Nd:GdVO₄ crystal, a maximum average green output power of 3.75 W was obtained at 50 kHz of pulse repetition frequency, giving an optical conversion efficiency of 25%, whereas the effective intracavity frequency-doubling efficiency was determined to be 72%. At the incident pump power of 12.8 W, the shortest laser pulse was achieved at a pulse repetition rate of 10 kHz, the resulting pulse width, single pulse energy, and peak power were measured to be 35 ns, 108 μJ, and 3.1 kW, respectively. Received: 18 May 2000 / Published online: 20 September 2000     

Modeling of laser-diode side-pumped continuous wave Nd:YAG/KTP green laser

By reasonably assuming the distribution of the pump light in laser medium, the equations about the absorption and the gain for the end-pumped lasers are applied to the side-pumped ones, and a theoretical model for laser-diode side-pumped continuous wave intracavity-frequency-doubling lasers is given, in which the thermally induced diffraction loss and the variation of the fundamental wave radii with the pump power are considered. By using a Z-type cavity, a laser-diode side-pumped continuous wave Nd:YAG/KTP green laser is realized. The threshold pump power is 15 W, and the highest output power of the green laser is 3.75 W at the pump power of 160 W, corresponding to an optical–optical slope efficiency 2.6%. The experimental results are consistent with the numerical solutions.     

Continuous-wave diode-laser end-pumped Nd:YVO4/KTP high-power solid-state green laser

A simple folded-cavity used for intracavity frequency-doubled Nd:YVO₄ laser was analyzed by transmission matrix and numerical calculation. We have selected a set of proper cavity parameters which can be used readily by operating at high power levels with low threshold, high efficiency, and wide dynamic operating range. 5.6-W TEM₀₀ green laser has been obtained at a 22-W pumping power and with an optical–optical conversion efficiency of 25.5%.     

One hundred and twenty one W green laser generation from a diode-side-pumped Nd:YAG laser by use of a dual-V-shaped configuration

To ensure high-average-power and long-lifetime second harmonic generation, a dual-V-shaped configuration was designed. In this thermally near-unstable resonator, large fundamental mode size in Nd:YAG rod and small one in LBO crystal could be generated, which improved both the beam quality and the power density. A green output power of 121 W with pulse width of 68 ns and repetition rate of 10 kHz was obtained. To the best of our knowledge, the dual-V-shaped configuration is the first time used for green laser with average output power of more than 100 W.