氙灯抽运将导致钕玻璃内的不均匀温升,由此带来空间频率较低的热畸变,成为整个光路中最主要的畸变源。研究了400 mm口径4×2组合式片状放大器的动态热畸变问题。初步研究结果表明,在现有抽运结构下,抽运能量导致钕玻璃片表面最大温升约为0.85 ℃;由此引起钕玻璃片的“S”形变,最大形变大约为1.7×10-6 m,最大应力约为65 kPa,整个动态波前畸变约为0.3λ,与美国劳伦斯·利弗莫尔国家实验室(LLNL)的实验值相符。在目前的抽运结构下,动态波前畸变满足设计要求。

Pumped with Xe-flashlamp will induce non-uniformity rising of temperature in the Nd:glass and brought wave-front distortion with low space frequency,which is the main aberration source of the amplifier. So the wave-front distortion of the assembled slab amplifier with 400 mm aperture is studied in this text. The calculating results indicate that,with presently pumping configuration,the temperature rise of the Nd:glass is about 0.85 ℃,the non-uniformity temperature distributing induced “S” shape distortion is about 1.7×10-6 m,and the thermal-stress is about 65 kPa,the total wave-front distortion is about 0.3λ,which matched the experiment value of the Lawrence Livermore National Laboratory (LLNL). With presently pumping configuration,pump-induced wave-front distortion is acceptable.