飞秒激光高效高分辨多尺度全息动态加工方法研究

Femtosecond laser two-photon processing and computer-generated hologram (CGH) are two newly developing frontier technologies. The former has many advantages such as real three dimensional fabrication ability, high resolution, tiny heat effect and wide processing materials.And the latter can realize flexible and controllable focus array by modulating the incident light field.There are some issues in current femtosecond laser holographic processing,such as controling the consistence of the space focuses, achieving high enough resolution and fabricating large scale devices.This program will take advantages of the two technologies and will be devoted to developing a new method for femtosecond laser dynamic holographic fabrication which has high efficiency, high resolution and multi-scale. The research contents include building a relationship model between CGH and target light field, design and optimization of three dimensional holographic algorithm according to the amplitude distribution in target light field, study on the processing technology of several typical materials and realization of some micro nano functional device manufacturing. The first innovation of this project is developing a control method to improve the space focus consistency with real-time aberration compensation. And the second is proposing a fabrication approach based on the processing units generated by dynamic holograpy. This program will lay theoretical and technological foundation for the new femtosecond laser micro nano fabrication method and will promote the wide application and industrialization of femtosecond laser micro and nano processing in our country.

飞秒激光双光子加工技术和计算全息技术是新发展起来的两种前沿技术。飞秒激光双光子加工具有真三维、高分辨、热影响小、加工材料广泛等优点；计算全息技术可以通过对光场的调制实现灵活可控的多焦点阵列。本申请将充分发挥两种技术的优势，针对目前飞秒激光全息加工中存在空间焦点一致性不易控制、分辨率不高、器件尺度小等缺点，发展一种高效、高分辨、多尺度飞秒激光三维全息加工新方法。项目主要研究内容有：建立从空间光调制器到目标光场的理论模型；根据目标光场振幅分布设计和优化三维全息算法并在空间光调制器上得以实现；进行几种典型材料的三维全息加工工艺研究，实现几种微纳米功能器件高效、高分辨、多尺度加工。本项目提出具有像差实时补偿的空间焦点一致性控制方法和利用动态焦点阵列生成基本单元进行加工具有新意。本研究将为发展高效高分辨多尺度飞秒激光加工方法奠定理论和技术基础，为我国飞秒激光微纳米加工技术的广泛应用和产业化做贡献。

在国家自然科学基金的资助下，本课题构建了基于液晶空间光调制器的飞秒激光全息加工系统；系统研究了计算全息与目标光场之间的关系，深入研究了计算全息对焦点位置、强度和焦斑形状的影响；完成了点阵、线、面、体等结构飞秒激光全息加工及算法优化；利用空间光调制器实现了基于贝塞尔光束、环形菲涅尔波带片、各向异性手型结构等光场调制及结构加工；完成了微光学元件、微流控器件等三维功能器件飞秒激光全息高效加工。此外，利用飞秒激光加工不同结构和尺寸的微柱阵列，实现液体驱动结构的微结构自组装，完成对微物体进行选择性捕获和释放。研究工作进展顺利，共计发表论文40 篇，国家发明专利授权1项，圆满完成了各项既定目标，为飞秒激光全息加工广泛应用打下了良好基础。