物像光栅自拼接技术和自拼接概念应用于光学系统的物理问题研究

To meet the requirement of development of large-aperture optical systems, grating tiling technique has been developed rapidly since the 90's of the last century in the world wide. The object-image grating self-tiling technique proposed by the proposer of this application opens an absolutely new way for the development of this research, which changed grating tiling from a technical problem challenging the limits to a common one and improved the optical effect of grating tiling to the near ideal condition. In order to utilize the object-image grating self-tiling technique in real optical systems, in this application, we plan to research several basic physical problems of the object-image grating self-tiling techique and self-tiling concept for using in different optical systems, which includes distribution of optics field, loop oscillation, forward and backward pulse sequence, optical modulation, mirror symmetry of groove density and surface curvature, and so on. During the research, we will set up the theoretical models of above physical problems, and carry out kinds of theory analysis and experiment verification to confirm the potential problems and the specific advantages of the object-image grating self-tiling technique and self-tiling concept for using in different optical systems. According to the analysis results, we will try to solve the existing problems and develop the related advantages to spread the application scope of the object-image grating self-tiling technique and self-tiling concept in kinds of optical systems. Besides, we will also try to transfer the self-tiling concept to different optical systems to meet different requirments.

为满足大口径光学系统的发展需求，自上世纪九十年代起光栅拼接技术在世界范围内呈现出快速发展的态势。申请人本人提出的物像光栅自拼接技术为此项研究的发展开辟了一条全新的途径，得到了国内外同行的认可。该技术使得光栅拼接不再是一项挑战技术极限的难题，同时其光学效果也达到了近理想状态。为实现物像光栅自拼接技术的实际应用，本申请计划研究物像光栅自拼接技术和自拼接概念在不同光学系统中应用时存在的诸多基础物理问题，包括：光场分布，回路振荡，前后向脉冲序列，光学调制，镜像对称条纹密度和面型曲率等。建立上述物理问题的理论模型，进行理论分析，开展实验验证，明确物像光栅自拼接技术和自拼接概念在不同光学系统中应用时存在的潜在问题和具备的独特优势。依据研究结果，解决问题、发挥优势，拓展物像光栅自拼接技术和自拼接概念在众多光学系统中的应用范围。此外，积极开展自拼接概念的移植工作以满足不同光学系统的不同需求。

超短超强激光是人类已知的最亮光源，能在实验室创造出前所未有的超高能量密度、超强电磁场和超快时间尺度综合性极端物理条件。国际上正在大力发展超短超强激光光源，欧盟Extreme Light Infrastructure（ELI）计划拟发展10拍瓦(1拍瓦等于10^15瓦)乃至200拍瓦大型超短超强激光装置。美国、俄罗斯、英国、法国、日本等国也积极开展各自的拍瓦级超短超强激光计划。我国中国科学院上海光学精密机械研究所近期摘得了5.3拍瓦的世界纪录桂冠。当前拍瓦级激光装置均基于啁啾脉冲放大技术，处于系统末级的脉冲压缩器是全系统的瓶颈。激光系统的输出能力越强，脉冲压缩器的规模就越大，特别是压缩器光栅的尺寸就越大。以位于捷克的ELI-Beanlines项目为例，当前压缩器光栅的尺寸需求已经达到了2米，远远超过了光栅的制备能力。目前国际上最大光栅为美国制备的0.9米，而我国目前的制备能力只有0.4米。由于对华禁运等因素，光栅尺寸不足已经严重制约了我国拍瓦级激光的发展。因此不得不采用光栅拼接技术来缓解光栅尺寸不足的压力。传统光栅拼接的高拼接难度和低光学效果不利于我国拍瓦级激光装置的研制。因此我们提出了一种新型技术叫做物像光栅自拼接，该技术大大缓解了上述两个问题。从目前来看物像光栅自拼接是解决拍瓦级超短超强激光压缩器光栅尺寸不足的一个好办法。本项目对于物像光栅自拼接应用在诸如超短超强激光装置的八个潜在物理问题进行了细致研究，并得以解决。通过实验演示利用该技术我们在钕玻璃皮秒激光和钛宝石飞秒激光中均获得了较好的脉冲压缩时空特性。可以确定的是该技术能够帮助拍瓦级激光装置解决压缩器光栅尺寸不足的问题，助力实现前所未有的超短超强激光输出。