利用全固态Nd:YVO4激光器的914 nm输出作为抽运源，对Nd:YVO4晶体进行基态高斯塔克能级共振抽运，获得了高效率的1064 nm激光输出。为解决基态高斯塔克能级共振抽运吸收差、光-光转换效率低的问题，详细分析了掺杂浓度、温度以及长度等晶体参数对抽运光吸收和激光转换效率的影响。在此基础上，使用长度为20 mm的Nd:YVO4晶体获得了相对入射抽运光56.9%的高光-光转换效率。914 nm基态高斯塔克能级共振抽运Nd:YVO4激光器的光-光转换效率达到了可与传统抽运相比拟的实用化水平。

报道了880 nm激光二极管(LD)共振抽运的连续波(CW)NdYVO4-PPLN内腔单谐振光学参量振荡器(ICSRO)。在21.9 W抽运功率下，获得了1.54 W的3.66 μm CW中红外闲频光输出，光-光转换效率为7.0%；与808 nm传统抽运相比，共振抽运ICSRO在振荡阈值、输出功率、转换效率和功率稳定性等方面都显示出明显优势。针对高抽运功率下逆转换过程影响单谐振光学参量振荡器(SRO)转换效率的问题，研究了振荡信号光的耦合输出透射率对SRO阈值和下转换效率的影响。通过提高振荡光输出镜透射率优化SRO阈值，可在高抽运功率下保持下转换效率的同时获得高效的信号光输出；21.4 W抽运功率下同时获得1.54 W闲频光和5.03 W信号光输出，总提取效率为30.2%。

针对常温工作条件下利用磷酸氧钛钾（KTP）晶体对钇铝石榴石（NdYAG）晶体1319 nm激光三倍频产生440 nm蓝色激光的实验，对三倍频KTP晶体的相位匹配角进行了理论计算和实验研究。通过多组色散方程得到KTP晶体的相位匹配角，并计算出相应的有效非线性系数。选取一组结果（θ=84.6°，φ=0°）对KTP晶体切割，利用一台1319 nm激光器，将晶体放入腔中，采用旋转晶体偏角和调节温度的方法寻找出三倍频KTP晶体最佳匹配角度（θ=85.04°，φ=0°）。该晶体经过重新切割，440 nm蓝色激光输出的光束强度有了明显的提高，最佳工作温度为18 ℃。

报道了利用半导体激光器(LD)端面抽运的钒酸钇(Nd:YVO4)激光器作为抽运源, 多周期周期极化铌酸锂(PPLN)为非线性晶体的连续波内腔光学参量振荡器(OPO)及基于此的连续波可调谐橙红光光源。为实现OPO的连续波运转, 采用了内腔抽运方式, 并对谐振腔进行了合理设计。实验得到调谐范围1406～1513 nm的信号光及3.66～4.1 μm的中红外闲频光连续波输出, 在10.9 W的LD功率下, 最大输出功率分别为输出波长1500 nm处的820 mW和3.86 μm处的195 mW, 相对LD功率的转换效率分别为7.5%和1.8%。利用BaB2O4(BBO)晶体对OPO的1064 nm抽运光和1.4～1.5 μm信号光进行内腔和频, 获得了调谐范围606～624 nm的橙红波段连续波输出, 最大输出功率为624 nm处的120 mW, 转换效率为1.1%。

在所有激光二极管(LD)侧面抽运的固体激光器的输出功率曲线中都存在一个平缓区域。通过对径向和切向热透镜焦距的理论计算, 发现平缓区域出现在径向稳区边缘, 在平缓区之后输出功率将继续升高, 并在切向稳区边缘达到最大值, 此时M2理论值最小。得出平缓区是由径向、切向稳区的共同作用导致的, 并且在切向稳区边缘可以实现高亮度激光器的结论。基于以上理论分析, 设计了一个具有简单平-平腔结构、LD侧面抽运的Nd:YAG高亮度激光器。实验中采用短腔型, 并使其工作在稳功率点, 当腔长为200 mm, 入射的抽运光功率为220 W时, 获得了输出功率为50 W, M2理论值为2的高亮度1064 nm连续激光输出。

We derive the threshold pump intensity for a singly resonant intracavity optical parametric oscillator (IOPO) based on a temporal coupled field model. Particular attention is paid to the dependence of the intracavity singly resonant OPO (SRO) threshold intensity on the signal wave output coupling. Meanwhile, a Nd:YAG laser pumped KTiOPO4 (KTP) IOPO for eye-safe laser output is studied experimentally. The experiment is performed with four signal wave output reflectivities of 60%, 70%, 80%, and 90%, respectively. The measured values are in good agreement with the theoretical results. With an output coupler reflectivity of 80%, a peak power of 70 kW at 1572 nm has been obtained at a repetition rate of 3.5 kHz. The pulse width is 4.9 ns. Such investigation is helpful to identifying suitable operational regime of low pump intensity.

We report a high-peak-power, high-repetition-rate diode-side-pumped Nd:YAG Q-switched intracavity optical parametric oscillator (IOPO) at 1.57 microns with a type-II non-critically phase-matched x-cut KTP crystal. The average power of 1.15 W at 1.57 microns is obtained at 4.3-kHz repetition rate. The peak power of the pulses amounts to 33.4 kW with 8-ns duration. The average conversion efficiency from Q-switched 1.064-micron-wavelength input power to OPO signal output power is up to 10.5%.

An all-solid-state quasi-continuous-wave dispersion cavity tunable Ti:sapphire laser pumped by a laser diode pumped frequency-doubled Nd:YAG laser is reported. Using a dense flint glass prism as the dispersion element, a tuning range from 730 to 880 nm with the linewidth of 3 nm and the pulse width of 17.2 ns was obtained. The maximum output power of this laser system was 5.6 W at 786.3 nm corresponding to an optical-to-optical conversion efficiency of 25.5% under the pump power of 22 W.

An efficient, stable diode-end-pumped simultaneous continuous-wave (CW) dual-wavelength laser operating at 1.319 and 1.338 μm in a Nd:YAG crystal has been demonstrated. A total output power of 6.3 W is achieved at an absorbed pump power of 15 W, with a slope efficiency of 43.5%. The instability of output power is less than 1%. With a type II critical phase-matched KTP crystal inserted into the cavity as frequency doubler, a maximum outputpower of 200 mW in red region is acquired. In addition, a six-wavelength laser operation at 1.319 μm, 1.338 μm, 1.356 μm, 659.5 nm, 669 nm, and 678 nm is observed.