主动冷却式一维变形镜技术研究

Research on the One-Dimension Deformable Mirror with Active Cooling System

根据高能固体板条主振荡功率放大(MOPA)激光放大器系统输出矩形光束在增益介质长度方向波前畸变的特点,针对性地研制了在一维方向上进行波前畸变校正的新型波前校正器,即一维变形镜(DM1D)。通过仿真模型对镜面厚度及粘接面形状等技术参数进行优化,设计了一个具有11通道的主动冷却型一维变形镜,全口径静态面形峰谷(PV)值为0.17μm,校正动态范围不小于5μm。采用主动冷却技术,使镜面在8 k W/cm2功率密度激光长时间照射情况下温升小于1℃,保持了强光作用下镜面面形的稳定性。在闭环校正试验中,光束质量β因子均值从8.82提高至4.38,有效地校正了光束波前畸变,验证了该一维变形镜在MOPA激光系统中的实用性。

According to aberration characteristic in length direction of rectangle beam from a master oscillator power-amplifier （MOPA） slab solid system, a new type of wavefront corrector named one-dimension deformable mirror （DM1D） with actuators arranged in one direction is developed. The key parameters such as the thickness of the reflecting mirror, the shape of the cementation face are analyzed and optimized by simulations. The surface of the DM1D is driven by 11 piezoelectric actuators, whose static peak to calley （PV） distance is less than 0.17 μm and which can provide an effective dynamic correcting range more than 5 μm. With activity refrigerating design, the temperature rise of mirror surface can be controled within 1℃, which is caused by the input high power laser with the power density of 8 kW/cm^2 in long time. The beam quality factor β of the output laser beam can be reduced from 8.82 to 4.38 by DM1D in closed loop experiment, proving that the aberration is effectively compensated. The correcting capability and practicability of the DMID are verified in more experiments.