885nmLD高重频侧泵Nd：YAG全固态激光器输出特性研究

对不同反射率和注入电流下885nmLD高重频侧面泵浦Nd：YAG全固态激光器的输出特性进行了实验研究，实验表明1064nm激光脉冲输出能量随注入电流的增加而增大，泵浦频率越高，脉冲输出能量增长越慢。以脉冲侧面泵浦Nd：YAG，在重复频率为60Hz、80Hz，注入电流为130A时，得到了输出透镜的最佳反射率都为73％，输出脉冲能量分别为62.1mJ，47.9mJ，光-光效率分别为13.29%、10.29%。     

LD列阵泵浦Nd:YAG连续激光器

介绍了一种二极管侧面泵浦的Nd:YAG连续激光器，采用了简单，实用的侧面泵浦结构，获得了37．9W的连续1064nm的激光多模输出，斜效率为31．5％，光准效率为23．7％，文中还对该泵浦头的热透镜效应作了测试。     

脉冲LDA侧面泵浦大能量Nd:YAG激光器时变热效应分析

建立了激光二极管阵列(LDA)侧面泵浦棒状Nd:YAG增益介质时变热效应理论计算模型。采用有限元Ansys软件模拟分析了脉冲LDA侧面泵浦大能量固体激光器的时变热效应特性。研究结果表明,所研究的脉冲LDA侧面泵浦大能量Nd:YAG激光器热效应具有时变特性,介质横截面内中心点处的稳态温度场分布随时间呈锯齿形周期变化,锯齿形变化频率为LDA泵浦频率,脉冲LDA泵浦参数对介质稳态温度场分布有较大影响。分析和计算了介质内热梯度、应力双折射以及激光晶体端面效应等导致的晶体热透镜焦距。计算表明,介质的热焦距主要来源于介质内温度梯度引起的热透镜焦距。     

LD侧泵浦Nd：YAG板条双程功率放大器初步研究

 对二极管激光侧泵浦Nd：YAG板条双程功率放大器进行了初步的研究,给出了激光器的数值模拟结果,建立了二极管侧面泵浦Nd:YAG板条激光主振荡-多程放大(MOPA)系统;在100Hz重复频率时,实验获得单脉冲能量为51.9mJ的输出,光束质量M ²小于2,脉冲能量起伏小于2%, 实验结果与数值计算结果相符合。     

大功率激光器的小型化研究

介绍了利用半导体激光二极管泵浦Nd :YAG固体激光器来实现激光器小型化的设计原理。重点说明了半导体激光二极管泵浦Nd :YAG固体激光器的基本原理和不同的结构形式。     

脉冲LDA侧面泵浦大能量Nd:YAG激光器时变热效应分析北大核心CSCD

建立了激光二极管阵列(LDA)侧面泵浦棒状Nd:YAG增益介质时变热效应理论计算模型。采用有限元Ansys软件模拟分析了脉冲LDA侧面泵浦大能量固体激光器的时变热效应特性。研究结果表明,所研究的脉冲LDA侧面泵浦大能量Nd:YAG激光器热效应具有时变特性,介质横截面内中心点处的稳态温度场分布随时间呈锯齿形周期变化,锯齿形变化频率为LDA泵浦频率,脉冲LDA泵浦参数对介质稳态温度场分布有较大影响。分析和计算了介质内热梯度、应力双折射以及激光晶体端面效应等导致的晶体热透镜焦距。计算表明,介质的热焦距主要来源于介质内温度梯度引起的热透镜焦距。     

百瓦级近衍射极限VCSEL泵浦激光器

报道了高功率、高光束质量的垂直腔面发射半导体激光器(VCSEL)侧泵的Nd:YAG激光振荡器。从VCSEL泵浦源的主动冷却的热沉结构出发,设计了5个227 W的VCSEL线阵,并且通过优化侧面泵浦大口径激光棒的结构,研制成了具备480 W输出能力的棒状激光模块,相应的光-光效率为49.7%。在此基础上,设计了一种高功率、高光束质量的VCSEL侧面泵浦棒状Nd:YAG激光振荡器。腔内插入望远镜光学元件,并通过优化各光学元件的参数使其工作在热近非稳区域,以达到增大基横模体积和抑制高阶横模目的。最终,获得114 W的输出功率,相应的平均光束质量因子M2为1.42。由于VCSEL具备优秀的波长-温度稳定性,这种高功率、高光束质量的VCSEL泵浦的固体激光器在工业、空间等领域,具有极为广阔的应用前景。     

LDA侧面Zigzag泵浦多边形薄片激光放大器模拟与实验研究

介绍了一种激光二极管叠阵（LDA）侧面Zigzag泵浦多边形薄片激光放大器构型，采用三维光线追迹方法进行了详细的模拟仿真，优化设计了此放大器系统的泵浦耦合结构，主要研究了多边形增益介质的掺杂离子浓度与侧面切角对介质内部泵浦光分布的影响。在晶体厚度1.5 mm、端面口径16 mm的条件下，侧面切角在35°～65°，Nd3+掺杂浓度为0.20 at.%～0.30 at.%时，模拟仿真中Nd:YAG多边形薄片对泵浦光的吸收分布较均匀，泵浦光分布均匀性均优于0.1，同时在实验中得到了平顶的荧光分布和增益分布。介质内储能的均匀平顶分布有利于实现高功率高光束质量的激光输出，为侧面Zigzag泵浦多边形薄片激光器系统的设计与进一步实验提供了重要参考。     

647W灯泵浦大功率连续Nd:YAG激光器

 报道了一台灯泵浦大功率连续Nd:YAG激光器。对影响大功率固体激光器模块输出功率和光束质量的主要因素进行了理论分析，并提出提高激光器效率的措施：对聚光腔的形状、结构和材料以及冷却方式，泵浦灯的参数和材料，激光晶体的参数和镀膜进行优化设计，采用径向固定的谐振腔镜。该灯泵浦YAG晶体棒总体电光转换效率为4%，光束质量为22mm·mrad，输出功率647W。     

采用曲率传感器测量热透镜焦距

 分析了用光栅型波前曲率传感器测量热透镜焦距的基本原理，针对高功率固体激光器的工作特点，结合实验现象推导了在热透镜效应较强时热透镜焦距变化的计算公式。对半导体二极管(LD)侧面泵浦的百W级Nd:YAG激光棒在泵浦电流为15~25 A时的热透镜焦距值进行了测量，讨论了可能存在的误差。实验现象和理论分析一致，测量的热透镜焦距值与理论值符合得较好。     

1064 nm Nd:YAG laser intracavity pumped at 946 nm

We present for the first time a Nd:YAG laser emitting at 1064 nm intracavity pumped by a 946 nm diode-pumped Nd:YAG laser. A 885 nm laser diode is used to pump the first Nd:YAG crystal emitting at 946 nm, and the second Nd:YAG laser emitting at 1064 nm intracavity pumped at 946 nm. We achieved an output power of 7.97 W at 1064 nm for an absorbed pump power at 946 nm of 9.55 W, corresponding to an optical efficiency of 83.4%. The beam quality M² quality factor is about 1.1 at the maximum output power.     

A 4.8-W M^2 = 4.6 Continuous-Wave Intracavity Sum-Frequency Diode-Pumped Solid-State Yellow Laser

A yellow continuous wave with beam quality M^2= 4.6 and output power of 4.8 W at 589nm is generated by intracavity sum-frequency mixing of 1064 nm and 1319 nm radiations of a Nd：YAG laser. To achieve high beam quality at high power, thermally near-unstable flat-flat resonators with two-rod birefringence compensation are designed to obtain the large fundamental mode size inside the Nd：YAG rods and the same beam width inside the KTP crystal. The optimal intracavity power ratio of both 1064nm and 1319nm beams is also considered. The output power fluctuation of the yellow laser remains less than 5% in four hours.     

108 W Nd: YAG ceramic laser with birefringence compensation resonator

The quartz rotator's effective birefringence compensation for ceramic Nd:YAG rods has been first demonstrated. Furthermore, a high output power continuous-wave laser is presented based on an optimized resonator made up of four Nd:YAG ceramic rods. By an appropriate design of the resonator, an output power of 108 W at 1064 nm is obtained. The corresponding optical-to-optical conversion efficiency is 16.8% and the slope efficiency is 28.1%. Meanwhile, the numerical analysis for output power is detailed.     

Properties of continuous-wave 1123 nm laser with diode-side-pumped Nd:YAG

Laser properties of diode-side-pumped Nd:YAG laser operating at 1123 nm are demonstrated. A 1.0 at % Nd-doped Nd:YAG rod with a size of Ø3 × 63 mm² is used as the active medium. Both radial and tangential thermal focal lengths of this side-pumped Nd:YAG rod are determined under lasing condition. The results show that the bifocusing strength of 1123 nm laser is larger than that of 1164 nm laser, and 1123-nm thermal focal lengths are shorter than those of 1064-nm laser due to higher quantum defect. Laser output performances of 1123 nm in terms of stability, output power and beam quality influenced by pump power at different cavity lengths are also discussed with a convex-piano cavity.     

High-power and high optical conversion efficiency diode-end-pumped laser with multi-segmented Nd:YAG/Nd:YVO_4

A novel flat-flat resonator consisting of two crystals(Nd:YAG + Nd:YVO_4) is established for power scaling in a diode-end-pumped solid-state laser. We systematically compare laser characteristics between multi-segmented(Nd:YAG + Nd:YVO_4) and conventional composite(Nd:YAG + Nd:YAG) crystals to demonstrate the feasibility of spectral line matching for output power scale-up in end-pumped lasers. A maximum continuous-wave output power of 79.2 W is reported at 1064 nm, with M_x~2= 4.82, M_y~2= 5.48, and a pumping power of 136 W in the multi-segmented crystals(Nd:YAG + Nd:YVO_4). Compared to conventional composite crystals(Nd:YAG + Nd:YAG), the optical-optical conversion efficiency of multi-segmented crystals(Nd:YAG + Nd:YVO4) from 808 nm to 1064 nm is enhanced from 30% to 58.8%,while the laser output sensitivity as affected by the diode-laser temperature is reduced from 55% to 9%.     

大功率准连续Nd:YAG陶瓷激光器研究

采用侧面环绕均匀排布的紧凑型抽运结构,实现了激光二极管阵列侧向抽运Nd∶YAG陶瓷激光器高效率激光输出。理论计算得到谐振腔输出镜的最佳输出耦合透射率为22.2%,并在输出耦合镜透射率为22%的条件下,用掺杂原子数分数为1%,尺寸为5mm×75mm的Nd∶YAG陶瓷棒,获得了平均功率大于230W的准连续1064nm激光输出,其光光效率和斜率效率分别高达52.4%和61%。并测得输出激光脉冲宽度为160μs,光谱线宽略小于0.8nm,光束发散角为16mrad。实验结果显示,Nd∶YAG陶瓷激光器输出功率Nd∶YAG单晶激光器相当。     

Compact corner-pumped Nd:YAG/YAG composite slab laser

Corner-pumping is a new pumping scheme in diode-pumped all-solid-state lasers, having such advantages as high pump efficiency, favorable pump uniformity and low cost. Compact corner-pumped Nd:YAG/YAG composite slab lasers at 1064 nm with low or medium output powers and high efficiency are demonstrated in this paper. Combined with intracavity frequency doubling by a LBO crystal, a corner-pumped Nd:YAG/YAG composite slab 532 nm green laser with a stable output is realized successfully. The experimental results show that corner-pumping can reduce laser costs greatly, release the thermal effects of slab crystals and improve the output beam quality, and that the new pumping scheme is feasible in the design of diode-pumped all-solid-state lasers with low or medium output powers.     

All-solid-state continuous-wave frequency doubling Nd:YAG/LBO laser with 8.2 W output power at 660 nm

An efficient and compact red laser at 660 nm is generated by intracavity frequency doubling of continuous wave (CW) laser operation of a diode pumped Nd:YAG laser at 1319 nm under the condition of suppression the higher gain transition near 1064 and 1319 nm under the condition of suppression the higher gain transition near 1064 and 1338 nm. With 40 W diode pump power and a frequency doubling crystal LBO, as high as 8.6 W of CW output power at 660 nm is achieved, corresponding to an optical-to-optical conversion efficiency of 21.5% and the output power stability in 8 h is better than 2.73%. To the best of our knowledge, this it the highest conversion efficiency of watt-level laser at 660 nm generated by intracavity frequency doubling of a diode end pumped Nd:YAG laser at 1319 nm.     

A tunable corner-pumped Nd:YAG/YAG composite slab CW laser

A corner-pumped Nd:YAG/YAG composite slab continuous-wave laser operating at 1064 nm,1074 nm,1112 nm,1116 nm,and 1123 nm simultaneously and a laser that is tunable at these wavelengths are reported for the first time.The maximum output power of the five-wavelength laser is 5.66 W with an optical-to-optical conversion efficiency of 11.3%.After a birefringent filter is inserted in the cavity,the five wavelengths can be separated successfully by rotating the filter.The maximum output powers of the 1064 nm,1074 nm,1112 nm,1116 nm,and 1123 nm lasers are 1.51 W,1.3 W,1.27 W,0.86 W,and 0.72 W,respectively.     

Comparison of Nd:YAG Ceramic Laser Pumped at 885nm and 808nm

Laser performance of 1064 nm domestic Nd：YAG ceramic lasers for 885 nm direct pumping and 808 nm traditional pumping are compared. Higher slope efficiency of 34% and maximum output power of 16.5 W are obtained for the 885nm pump with a 6ram length 1 at.% Nd：YAG ceramic. The advantages for 885nm direct pumping are discussed in detail. This pumping scheme for highly doping a Nd：YAG ceramic laser is considered as an available way to generate high power and good beam quality simultaneously.