Ti:sapphire Laser Pumped Yb:YAG Laser with Cr4+:YAG as a Passive Q-switch

The Ti: sapphire laser pumped Yb: YAG passively- Q- switched laser with Cr4+: YAG as a saturable absorber experiment was performed.     

Flash-Lamp-Pumped Acousto-Optic Q-switched Cr-Tm:YAG Laser

High-power Q-switched solid-state lasers operating at 2 μm wavelength are needed for many applications. Using flash-lamp pumping, we developed an acousto-optic Q-switched Cr-Tm:YAG laser and realized single transverse mode oscillation with a maximum pulse energy exceeding 0.8 J when the repetition frequency was 1 Hz. The pulse width and the corresponding peak power were 135 ns and 5.9 MW, respectively. To our knowledge, this is the highest output power of AO-Q-switched Cr-Tm:YAG lasers have ever reported.     

激光二极管端面抽运的棒状Yb：YAG激光器

分析了影响激光二极管抽运Yb：YAG激光器调Q效率的参量，推导了激光二极管端面脉冲抽运Yb：YAG晶体的速率方程，解出了双程抽运情况下的净抽运量子产率。利用数值计算方法，模拟了净抽运量子产率与晶体长度，抽运光脉冲宽度等关系，得出晶体长度的优化可以提高Yb：YAG激光器输出效率。计算了词Q Yb：YAG激光器的最大增益、最大储能，分析了放大自发辐射对于Yb：YAG能量存储的影响。同时给出了激光二极管端面抽运调Q Yb：YAG优化设计方法。这些分析和计算为实际器件的研制提供参考。     

激光二极管泵浦的高重复频率Nd：YAG激光器

报道两个１．５Ｗ连续激光二极管端面泵浦的声光调ＱＮｄ：ＹＡＧ激光器，输出激光脉冲的最高重复频率为３０ｋＨｚ重复频率１ｋＨｚ时，最窄脉宽为１２ｎｓ，最高峰值功率为１２．１ｋＷ。     

多波长半导体激光阵列端泵Nd:YAG脉冲激光器

研制了无温控多波长激光二极管阵列端面泵浦Nd：YAG电光调Q激光器。采用4 000 W多波长准连续激光二极管阵列作为泵浦源,快轴准直镜与透镜导管作为泵浦耦合系统,端面泵浦φ6 mm×60 mm的Nd：YAG晶体,并采用RTP晶体进行电光调Q实验。在重复频率5 Hz、室温（25℃）时,激光器获得了最大输出能量74.4 mJ、脉宽15 ns的1 064 nm脉冲激光输出,光光转换效率达到11%。在25~55℃的工作温度下,对多波长LDA的光谱特征与激光器的输出特性作了测试,激光器输出能量随着工作温度的上升而先迅速下降再逐步保持稳定,当重复频率分别为5 Hz和10 Hz时,激光器对应的最低输出能量分别为48 mJ与37 mJ。     

激光二极管侧面泵浦的高效率Nd：YAG激光器

用准连续激光二极管列阵侧面泵浦Ｎｄ：ＹＡＧ固体激光器，获得３９．５ｍＪ的静态输出，器件重复频率为５０Ｈｚ，效率最高达３９．５％，对该器件进行了细致的实验研究，验证了理论计算的正确性，并对实验结果进行了分析。     

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。     

Efficient High-Power Ho:YAG Laser Pumped by Dual-End-Diode-Pumped Tm:YLF Laser

We report a Ho:YAG (Ho-doped yttrium aluminum garnet) laser pumped by a dual-end-diode-pumped Tm:YLF (Tm-doped yttrium lithium fluoride) laser to obtain an efficient experimental device with high output-power characteristics. We study the influence of the specific values of the output coupling mirror transmittance, the resonant cavity length, and the radius of curvature of the output coupling mirror on the Ho:YAG laser output characteristics. Under optimum experimental conditions, under which the output coupling mirror transmittance was 30%, the resonant cavity length was 25 mm and the output coupling mirror radius of curvature was 300 mm, and the maximum pumping power of the dual-end-diode-pumped Tm:YLF laser was 15.2 W. We obtain an efficient high-power 2.122-μm laser output of 7.98 W from the Ho:YAG laser. The optical-to-optical conversion efficiency is 52.5%, and the beam quality factor figures are M _x ² ?=?2.89 and M _y ² ?=?2.97.     

An Ho:YAG Laser with Double-Pass Pumping and the ZnGeP2 OPO Pumped by the Ho:YAG Laser

We report an efficient Ho:YAG laser end pumped by Tm:YLF lasers with double-pass pumping. We achieve the maximum continuous wave (CW) output power of 46.0 W with a single-pass pumping and 50.2 W with a double-pass pumping, corresponding to a slope efficiency of 58.0% and 62.8%, respectively. In addition, we use the Ho:YAG laser as a pumping source of the ZnGeP₃ optical parametric oscillator (OPO) and obtain the maximum average output power of 14.2 W with a linear cavity and 17.0 W with a ring resonator, respectively.     

Highly Efficient Diode-Side-Pumped Six-Rod Nd:YAG Laser

We have demonstrated a highly efficient, high average output power laser based on the optimized resonator made up of multiple Nd:YAG rods. The laser consists of three groups, each of which contains two rods with one quartz 90° rotator between them. By a desirable design of the resonator, the average output power of 1906W at 1064nm is reached with repetition rate of 1.1kHz. The optical to optical conversion efficiency is up to 50.8% with the pulse width 224μs and it is the highest conversion efficiency of six rods resonator.     

Laser properties of YAG: Nd,Ti

YAG: Nd containing 10^–3 wt% Ti showed slightly increased losses at 1·064 m but a substantially increased gain coefficient if compared with a material containing no Ti. The increased losses may be attributed to the increased absorption near 1·064 nm and the increased gain to the better energy coupling among Nd³⁺ ions occupying nonequivalent sites due to the presence of Ti³⁺ ions. YAG: Nd, Ti may be used as a high performance pulsed laser.     

基于4 kW YAG激光器的激光拼焊焊接工艺

分析了激光拼焊工艺特征,重点研究了在大功率固体激光器条件下,激光拼焊焊接工艺中激光功率、焊接速度和离焦量等因素变化对焊接质量的影响,得出了变化规律曲线。并系统全面地研究了目前汽车常用板材全厚度系列激光拼焊工艺,采用叠代寻优的方法获得到了适用于全自动激光拼焊生产线的优化工艺规范。     

连续激光二极管抽运的调Q高重复率Nd:YAG激光器研究

报道了由１５Ｗ连续激光二极管端面抽运的Ｎｄ：ＹＡＧ激光器,自由运转时输出功率达到４．５Ｗ,斜效率达到４４％,声光调Ｑ的重复率由３～６５ｋＨｚ可变。１０ｋＨｚ时,峰值功率达到２８ｋＷ,脉宽８ｎｓ。还分析了激光二极管抽运的声光调Ｑ高重复率激光器设计中的几个重要因素。从理论上分析了不同频率时激光单脉冲能量、斜效率产生区别的主要原因。     

104 W内腔倍频全固态Nd:YAG绿光激光器

报道了一台高功率内腔倍频全固态Nd:YAG绿光激光器,针对KTP晶体热效应和激光热稳定腔,采取了对KTP晶体进行低温冷却的优化措施,以便减少KTP晶体的热效应导致的相位失配,同时兼顾了Nd:YAG棒的热致双折射效应和KTP晶体热透镜效应,设计了热稳定谐振腔;实验中采用80个20 W激光二极管阵列侧面抽运Nd:YAG棒和Ⅱ类相位匹配KTP晶体(在27℃时相位匹配角为φ=23.6°;θ=90°,尺寸为7 mm×7 mm×10 mm)内腔倍频技术,谐振腔腔长为530 mm,KTP晶体的冷却温度为4.3 ℃,抽运电流为18.3 A时,实现平均功率达104 W、脉冲宽度为130 ns的532 nm激光输出;其重复频率为20.7 kHz.光-光转换效率为10.2%.     

激光二极管端面泵浦Yb∶YAG薄片激光器的热效应

通过激光二极管端面泵浦Yb∶YAG薄片工作特点分析,建立了符合实际情况的热模型.热模型考虑了介质薄片具有端面绝热、周边恒温冷却、后端面镀膜达到充分利用泵浦光能量等特点.分析并建构了Poisson方程新的求解方法,得出了Yb∶YAG薄片内部温度场以及泵浦端面热形变场的一般解析表达式.理论研究结果表明:若激光二极管泵浦功率为20 W、耦合到薄片泵浦面的泵浦光高斯半径为250 μm时,长度3 mm、半径1.5 mm的5.0at.%Yd:YAG薄片泵浦端面的最高温升为44.5℃,最大热形变量为0.83 μm.     

Laser and thermo-optical investigations of Nd:YAG ceramics

The ‘wet’ technology was implemented for processing of Nd:YAG ceramics. The samples of disk, rod, slab shapes with 1–2% Nd dopant were fabricated and tested. Several method of optical characterization were applied. Near 80% transmission and scattering losses <0.2 cm⁻¹ were demonstrated. The laser action with 34% slope efficiency was obtained for the best case. To characterize the spatial inhomogeneities of output parameters “half-microchip configuration” with output coupler formed by uncoated output facet of plane parallel ceramic sample was implemented. Thermally induced aberrations and birefringence observed in Nd:YAG ceramic of disk samples under high heat load were examined and compared with numerical models.     

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。     

用半导体可饱和吸收镜进行LD泵浦Yb∶YAG 激光器被动锁模研究

采用不同的半导体可饱和吸收镜, 实现了940 nm半导体直接泵浦Yb∶YAG激光器被动锁模, 得到了输出中心波长分别在1030 nm和1050 nm, 光谱半宽（FWHM）分别为1 nm和2 nm的稳定锁模脉冲序列, 其重复频率分别为190.24 MHz和178.6 MHz. 泵浦光为4W时, 两种波长的平均输出功率分别为80 mW和60 mW.     

激光二极管抽运Cr4+:Nd3+:YAG自锁模自调Q激光器

采用光纤耦合半导体激光抽运,实现了Cr4+:Nd3+:YAG自锁模自调Q激光器1.06üm激光输出.当抽运功率超过阈值2.83 W时,激光器便运转在调Q锁模状态,其锁模调制深度达到80%以上.当抽运功率最大为5.72 W时,平均输出功率为233 mW,相应调Q包络的单脉冲能量为16.5üJ,调Q包络的脉冲宽度大约为120 ns.调Q包络中锁模脉冲之间的间隔为2.8 ns,这与光子在谐振腔内的往返时间相一致,对应的重复率为357 MHz,锁模脉冲宽度估计为560 ps.利用双曲正割函数,考虑腔内光子数密度的空间高斯分布、增益介质的受激辐射寿命和饱和吸收体的激发态寿命对激光特性的影响,建立了描述Cr4+:Nd3+:YAG晶体自调Q自锁模动力学过程的速率方程组.数值求解该方程组,与实验结果符合较好.