Author Affiliations
Abstract
Research Center of Laser Fusion, CAEP, P.O. Box 919-988, Mianyang 621900, China
Thermal stress can induce birefringence in a laser medium, which can cause depolarization of the laser. The depolarization effect will be very severe in a high-average-power laser. Because the depolarization will make the frequency doubling efficiency decline, it should be compensated. In this paper, the thermal characteristics of two kinds of materials are analyzed in respect of temperature, thermal deformation and thermal stress. The depolarization result from thermal stress was simulated. Depolarization on non-uniform pumping was also simulated, and the compensation method is discussed.
depolarization depolarization compensation thermal birefringence High Power Laser Science and Engineering
2015, 3(1): 010000e9
Author Affiliations
Abstract
Research Center of Laser Fusion (RCLF), CAEP, P.O. Box 919-988, Mianyang, Sichuan 621900, China
The high repetition rate 10 J/10 ns Yb:YAG laser system and its key techniques are reported. The amplifiers in this system have a multi-pass V-shape structure and the heat in the amplifiers is removed by means of laminar water flow. In the main amplifier, the laser is four-pass, and an approximately 8.5 J/1 Hz/10 ns output is achieved in the primary test. The far-field of the output beam is approximately 10 times the diffraction limit. Because of the higher levels of amplified spontaneous emission (ASE) in the main amplifier, the output energy is lower than expected. At the end we discuss some measures that can improve the properties of the laser system.
Yb:YAG V-shape amplifier water-cooled 10 J laser system High Power Laser Science and Engineering
2014, 2(3): 03000e27
中国工程物理研究院 激光聚变研究中心， 绵阳 621900
为了实现高功率Yb∶YAG激光器的高效冷却，对大口径片状Yb∶YAG激光器的水冷结构进行了设计，采用有限元方法对该结构的传热效果进行了数值模拟，得到了该结构的表面对流传热系数、换热面的温度分布等参量。结果表明，该设计可以得到均匀的传热系数分布和温度分布，传热系数达到1.8×104W/(m2·K)，介质表面温差在1K以内，换热效果良好。
激光技术 对流换热 高功率激光器 传热系数 温度分布 laser technique heat convection high power laser coefficient of heat transfer temperature distribution
1 清华大学 精密测试技术与仪器国家重点实验室,北京 100084
2 中国工程物理研究院 激光聚变研究中心,绵阳 621900
为了实现热容激光器远场可聚焦性的实时控制,采用角锥棱镜阵列作为准相位共轭反射镜对光束波前进行被动式实时补偿。详细研究了阵列角锥棱镜谐振腔的光学特性,通过优化谐振腔的构型,进行腔内滤波,抑制角锥之间的共轭模式,获得了在保持90％输出能力条件下的单模输出,中心主斑能量集中度提高了约4.5倍,远场可聚焦性与传统的平-凹腔比提高约10倍。结果表明,角锥棱镜阵列谐振腔具有热不灵敏的特性,可显著提高热容激光器的远场聚焦能力。
激光技术 单模 热不灵敏谐振腔 可聚焦性 laser technique single mode thermal insensitive cavity focusing capability
中国工程物理研究院 激光聚变研究中心,绵阳 621900
为了提高抽运效率、改善抽运均匀性、克服热退偏的影响,建立了一套V型有源镜构型热容激光器,采用数值模拟与实验研究相结合的方法,对激光介质热分布进行了研究。数值模拟充分考虑了内热源的分布不均匀性,分析了激光介质的3维热分布。实验中采用热像仪对激光介质的表面温度进行了无接触测量。数值计算和实验研究结果具有较高的一致性。研究结果表明,该激光器构型对于提高热分布均匀性有较大的帮助。
激光技术 热分析 有限元 无接触测量 laser technique thermal analysis finite element non-touch measurement
中国工程物理研究院 激光聚变研究中心，绵阳 621900
为了研究布氏角片状激光器能量转换效率，提高激光器系统转换效率，采用实验的方法，对影响片状激光器转换效率的主要因素进行了理论分析并进行了实验验证，取得了能量输出与激光腔内损耗关系的数据。结果表明，多片结构带来的腔内固有损耗导致了激光器总体效率低下，由布氏角构形产生的腔内动态损耗限制了激光器连续工作能力，抽运损耗也对激光器能量转换效率有一定影响。
激光技术 片状激光器 腔内损耗 动态损耗 laser technique disk laser intracavity loss dynamic loss
