铁电畴结构高精度高分辨率实时动态三维检测新方法研究

Ferroelectric domain engineering has been extensively exploited for various quasi-phase-matched (QPM) nonlinear applications, electro-optical scanner and electro-optical switch, and has become the focus of ferroelectric research. As one of the most important parts, the real-time dynamic three-dimensional (3D) detection of domain structure with high precision and high resolution has the great significance and value for the theoretical investigation and domain engineering application. However, the exciting technique cannot meet the demand. This project suggests a new detection method of domain structure based on acoustooptic frequency shift in order to acquire the real-time dynamic three-dimensional information during domain inversion in LiNbO3 and LiTaO3. With the Jamin plates as the main structure, the system uses the Direct Digital Synthesize (DDS) technology to drive the acousto-optic deflector in order to realize the high-speed switch of fringe frequency. At the same time, the microscope technology is also used to enhance the lateral resolutions of testing system. In this case, the real-time 3D detecting of domain inversion can be carried out. In addition, the improved time-domain phase-unwrapping technology can be adopted to overcome the shortcomings of present digital holography so that the proposed method is not limited to the crystal's thickness and longitudinal depth of reversed domain structure. The longitudinal measurement precision can reach milliradian and the lateral measurement resolution can reach submicron. The technique can be applied to the real-time detection and control of domain inversion in order to produce the excellent PPLN. The realized technique in this project will have the great significance and value on the theoretical investigation and domain engineering application in the future.

铁电畴工程广泛用于准相位匹配非线性光学、电光扫描器和电光开关等领域，成为近年来铁电研究的热点。畴反转结构检测方法的研究已经成为铁电畴工程研究的重要组成部分，开展畴反转结构的高精度高分辨率实时动态三维检测具有重大的理论意义和工程应用价值,然而目前的检测技术均无法满足要求。本项目以获取铌酸锂和钽酸锂晶体畴反转实时动态过程的三维信息为目标，提出一种基于声光频移的畴结构检测方法，以雅敏干涉平板为主体，采用直接数字频率合成技术驱动声光偏转器，实现干涉条纹的高速变频，辅以显微技术，采用改进的时域相位解包裹技术克服现有数字全息干涉术不足，使检测范围不受晶体厚度和畴反转纵向深度的限制，具有更高的纵向检测精度和横向分辨率，纵向精度达到毫弧量级，横向分辨率达到亚微米量级，应用于实时检测和控制，制作优良的周期反转畴结构。本项目技术的实现对畴反转物理机制的深入研究和铁电畴工程的未来发展具有重要理论意义和应用价值

铁电畴工程广泛用于准相位匹配非线性光学、电光扫描器和电光开关等领域，但是现有的检测技术无法满足畴反转结构高精度高分辨率实时动态三维检测的要求。本项目以获取铌酸锂和钽酸锂晶体畴反转实时动态过程的三维信息为目标，首次研制了基于声光频移的铁电畴反转显微干涉检测系统，以雅敏干涉平板为主体，采用直接数字频率合成技术驱动声光偏转器，实现了干涉条纹的高速变频，与显微成像系统结合，实现了铁电晶体畴结构的高精度高分辨实时动态三维检测；研制了多方向矢量剪切的横向剪切干涉测量方法，实现了检测精度的提高和干涉图像处理算法的优化；首次研制了基于虚拟结构探测的高速超分辨线扫描成像系统，在不增加系统光学复杂性的前提下，能够实现横向分辨率超越理论衍射极限，达到亚微米量级；在512像素×512像素的视场下最大扫描采样帧率达到127帧/秒；首次结合离轴数字全息显微术和虚拟结构探测超分辨成像技术，以高速正交线扫描共焦数字全息显微成像光路为主体，设计了激光诱导铌酸锂/钽酸锂晶体亚微米量级畴反转高速超分辨实时动态三维检测系统；首次实现了飞秒激光诱导铌酸锂晶体铁电畴反转高精度高分辨率实时动态三维成像，深入研究了飞秒激光诱导铌酸锂晶体的畴反转动态物理机制；首次设计了基于达曼光栅分束的多路并行激光诱导铌酸锂/钽酸锂晶体三维微纳畴反转系统，通过达曼光栅的分束与光束整形，在纳米量级超高精度的三维扫描驱动下，实现多路并行飞秒激光束同时对铌酸锂晶体进行曝光诱导，同时对诱导激光束进行精确的曝光控制，实现高分辨率、高质量的快速并行飞秒激光诱导三维微纳畴反转的目的，辅以高速超分辨实时动态三维检测系统，制作一维和二维周期微纳反转畴结构。本项目先后发表标注引用论文36篇，包括SCI论文15篇，发表SPIE会议论文（EI收录）8篇，发表国内核心期刊论文（EI收录）13篇，授权发明专利22项，培养博士研究生4名，硕士研究生4名。