【作者】 张祎；

【导师】 吕志伟；

【作者基本信息】 哈尔滨工业大学 ， 物理电子学， 2006， 硕士

【摘要】 随着惯性约束聚变(ICF)激光驱动器研究的开展,需要高能量、高光束质量的激光输出,光学相位共轭技术因其自动有效的控制光束和修正任意波前畸变而备受瞩目。其中,受激布里渊散射(SBS)具有高转换效率、相位复共轭、脉宽压缩等特性,能实时补偿光学系统热畸变和材料不均匀性等因素带来的波前畸变,提高光束质量和聚焦功率密度,大大降低高能激光系统的规模和造价,因而在ICF激光驱动器研究中具有重要意义。但是由于受到其它非线性效应的限制,SBS激光系统的输出能量都还不能满足运用到ICF激光驱动器中的要求。因此,本文开展了适合高能激光系统的SBS相位共轭镜相位共轭特性的实验研究,为今后在高能激光系统中设计和应用独立双池SBS相位共轭镜提供实验参考。本论文主要研究工作及结论如下:一、通过对当前国内外高能SBS相位共轭镜技术研究进展以及SBS相位共轭镜在ICF激光驱动器中应用的分析,提出了基于高能激光抽运的高负载独立双池SBS相位共轭镜方案的设计,并对激光系统的增益特性和能流分布进行了模拟。二、对高能激光系统前端进行了集成实验,得到了较好的近场光斑,长脉冲工作方式下达到了百焦耳级的能量输出,稳定度在5%以内。三、在独立双池SBS相位共轭镜中,对能量反射率、远场相位共轭保真度、脉宽压缩比等参数受种子泵浦光与放大抽运光能量比的影响规律进行了实验研究。四、在高能激光系统中应用独立双池SBS相位共轭镜,在7J能量注入下,经过振-放双程放大,得到13J能量的激光输出;在泵浦能量高出阈值几百甚至上千倍时的能量反射率可以达到65%左右,保真度达80%以上;证明实验中设计的独立双池SBS相位共轭镜结构具有较高的负载能力,是高效的。五、在大口径(Φ64mm)高能激光系统中应用独立双池相位共轭镜并对比普通单池进行了泵浦能量对能量反射率和远场相位共轭保真度及其稳定性影响的实验研究。得到了它们的曲线变化规律。在得到了较高的远场保真度的同时,也对SBS近场保真度进行了定性研究,获得了较好的SBS近场更多还原

【Abstract】 As the development of Inertial Confinement Fusion (ICF), the laser output with high energy and high light beam quality is needed. People focus attention on optics phase conjugation technique for it can control light beam and correct wave-front aberrance. Thereinto, Stimulated Brillouin Scattering (SBS) has the characters of high conversion efficiency、phase conjugation、pulse compression. It can compensate wave front aberrance, improve light beam quality and power intensity, effectively reduce laser system scale and cost. Thus it has very important significance in ICF research.However, because of limits of other non-liner effect, SBS laser system’s energy output can not satisfy the request of applying on ICF laser drivers. Thus, this paper develops the research of SBS phase conjugation characters adapting to large caliber high energy lasers.The main contents and conclusion are as follows:1. SBS character research based on high energy laser and high load phase conjugaton mirror (PCM) is proposed. And the plus character and energy current distributing is simulated.2. The high energy laser system gains hundred J output without SBS phase conjugation mirror, the stability is within 5%.3. The experiment research of the ratio of seed pump and amplifier pump’s influence on energy reflectivity、far field phase fidelity、pulse compression ratio is performed.4. The high energy laser system gains 13J output with 7J input on SBS phase conjugation mirror, energy reflectivity achieves about 65% when pump energy is higher than SBS threshold hundreds times, and phase conjugation fidelity reaches above 80%. The independent two-cell SBS phase-conjugation mirror has much higher load capability and is higher efficient.5. Compared with general single cell the experiments of the influence of pump energy on energy reflectivity、phase conjugation fidelity and their stabilities have been performed on this system. The curve changing laws are achieved. And experiments also get better near field fidelity at the same time更多还原