| 题名 | 偏振光束同轴合成及群延迟色散测量技术 |
| 作者 | 董洪成 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 邵建达 |
| 关键词 | 相干叠加，偏振合成，同轴合成，合成效率，偏振转换效率，群延迟色散 |
| 其他题名 | Polarization Beam Coaxial Combination and Group Delay Dispersion Measurement Technique |
| 中文摘要 | 光束合成技术克服了单个激光器输出功率有限的缺点，是获得大功率高光束质量激光束的有效途径。群延迟色散镜已成为超短超快激光器中补偿系统色散及压缩脉宽的主要元件，研究群延迟色散测量技术对色散镜的发展是必要的。目前，光束合成及GDD测量技术都是研究的热点，本文以讨论偏振光束合成方法及建立GDD测试装置为主要目的，分别从以下几个方面展开了基础性的研究： 采用数值模拟方法研究了矩形阵列光束的合成效果，计算和分析了不同合成方式时的峰值强度及光束质量，讨论了光束束腰、相位及阵列结构等参数的影响，对同轴与非同轴合成、相干与非相干合成的特点进行了比较和总结。所得结果丰富了光束合成的理论，对开展实验研究有指导意义。 提出了偏振光束合成的方法，分析了两束光的振幅比和相位差变化的影响，认为等强度合成是最佳的实验方式。讨论了高斯光束的叠加及偏振光的转换，设计了薄膜型相位延迟器。提出基于主振荡能量放大结构的多光束偏振合成系统，对系统放大能力进行了分析。 开展了四束光的合成实验，合成光束的光束质量与初始光束相同。对合成损耗进行了详细的分析，认为由于调整精度限制，光束之间存在平行误差，既传播波前不平行，这是导致合成损耗的主要因素。通过改善调整精度，单元合成效率大幅提高，超过90%。分析了多纵模偏振光束合成的光程差控制问题，得到了控制精度、合成效率与激光增益线宽的关系，并给予实验验证。相对于其它相干合成方案，多模偏振光束合成具有较高的可实施性。 建立了迈克尔逊白光干涉仪，对色散镜进行了准确测量。实验发现：由于没有办法使两光束干涉时的波前完全平行，测量结果给数据处理带来了麻烦。通过分析，采用pi相位差离散点拟合法，避开了波前平行误差，成功处理了测量数据，测量精度优于8平方飞秒 。 |
| 英文摘要 | Due to overcoming the defect of the limited output power for a single laser, beam combination is an effective way of obtaining a laser beam with higher power and better beam quality. Group delay dispersion mirrors have been the main components of compensating the system dispersion and compressing the pulse width for ultrafast lasers, so it is necessary to study GDD measurement for the development of dispersion mirror. Beam combination and GDD measurement technique have been the research hotspots at present. In this dissertation, aiming at discussing polarization beam combination method and building GDD testing device, we have carried out a fundamental research in the following respects: The combination effect of a rectangular array beams was studied through numerical simulation method. The peak intensity and M2 factor for different combination methods were analyzed, and the impacts of the parameters such as beam waist, phase and array structure on combination were discussed. The features between coaxial and array combination, as well as coherent and incoherent combination were compared and summarized. The conclusions enriched the theory of beam combination and had guiding significance for experiments. The method of polarization beam combination was proposed. By analyzing the impact of the change of amplitude ration and phase difference, the combination of two beams with same intensity was considered as the best way. Gaussian beam superposition and polarization conversion were discussed, and a new film-type phase retarder was designed. A multi-beam combination system based on master oscillator power amplifier was presented, the amplification capacity of the system was also analyzed. An experiment of combining four beams was carried out, the beam quality of the combined beam was same as the seed beam. Through detailed analysis of combination losses, we considered the parallel error between beams originated from adjustment accuracy was the main factor of causing combination loss. By improving the adjustment accurary, the unit combination efficiency could be greatly increased to over 90%. Optical path control of multi-longitudinal mode polarization beam combination was analyzed; the relationship between control precision and combination efficiency as well as laser gain line-width was derived theoretically and verified experimentally. Compared to other coherent combination schemes, the feasibility of implementation of multi-mode polarization beam combination was much higher. A Michelson white light interferometer was built for measuring GDD mirror. Because there was no way to make the wave-fronts of the two beams parallel fully, some problems were encountered when calculated the measured results directly. By analyzing, a method of fitting discrete points of pi phase difference, which was not restricted by wave-front parallel error, was used for data processing successfully, and the measurement accuracy was better than 8 fs^2 |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15287]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 董洪成. 偏振光束同轴合成及群延迟色散测量技术[D]. 中国科学院上海光学精密机械研究所. 2009. |
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