实时动态全息3D显示用掺钼系列铌酸锂晶体的研究

Real-time dynamic holographic 3D display is a new kind of display technologies that can realize true 3D dynamic images for viewing with naked eyes, and has the extremely broad application prospect. Lithium niobate crystal is one of the important dynamic holographic medium, but slow response speed limits its application in the real-time dynamic holographic 3D display. The results of the preliminary research showed that high valence molybdenum-doped lithium niobate series crystals, which was doping based on Nb-site, had fast response in visible region and are very promising used for real-time dynamic holographic 3D display. In this project, we are planning to find out the microscopic mechanism for improving the photorefractive response speed of lithium niobate crystals by doping molybdenum ions on Nb-site, and reveal the carriers transport process. We will further master the adjusting and controlling technology for improving the crystals response speed. Meanwhile, we will find the small size pulse lasers whose pulse width can match with molybdenum-doped lithium niobate series crystals, which can control the visible response speed of the crystals at the level of millisecond, as well as keep them have high saturation diffraction efficiency, and then realizing real-time dynamic holographic 3D display. The implementation of this project is not only beneficial to deeper understanding the essence of fast response for lithium niobate crystals doped by photorefractive ions on Nb-site, but also providing the solution for developing miniaturization and portable real-time dynamic holographic 3D display system.

实时动态全息3D显示是一种能够实现裸眼可视真三维动态图像的新型显示技术，具有十分广泛的应用前景。铌酸锂晶体是重要的动态全息介质之一，但响应速度慢限制其应用于实时动态全息3D显示。申请人前期研究发现，基于Nb位掺高价态钼的系列铌酸锂晶体在可见光波段具有快响应，极有希望用于实时动态全息3D显示。本项目拟在此基础上，弄清基于Nb位掺杂的钼离子提高铌酸锂晶体光折变响应速度的微观机制，揭示载流子的输运过程，掌握进一步提高晶体响应速度的调控技术，同时找到脉冲宽度与掺钼系列铌酸锂晶体相匹配的小型脉冲激光器，既能够将晶体在可见光波段的响应速度控制在ms量级，又能使晶体保持较高饱和衍射效率，并实现实时动态全息3D显示。本项目的实施不仅有利于更深层次地理解基于Nb位掺杂光折变离子使铌酸锂晶体具有快响应的本质，还有助于为小型化、便携式实时动态全息3D显示系统的开发提供解决方案。

实时动态全息3D显示是一种能够实现裸眼可视真三维动态图像的新型显示技术，具有十分广泛的应用前景。铌酸锂晶体（LiNbO3, LN）是重要的动态全息介质之一，但响应速度慢限制其应用于实时动态全息3D显示。本项目自实施以来，围绕提高晶体响应速度的调控技术、快响应的微观机制、实现实时动态全息显示等方面开展研究，取得了一系列研究进展。利用极化工艺改变氧化/还原状态、不同抗光折变元素与Mo共掺、引入特殊电子结构的Bi离子等方法显著提升了LN晶体的光折变响应速度，发现提高极化电流强度能够显著提升晶体的光折变响应速度10-60倍；Mg2+、Zn2+、In3+、Zr4+、Hf4+等不同价态的抗光折变离子与Mo共掺杂能够缩短铌酸锂晶体的响应速度至百毫秒量级，抗光损伤能力可提升3倍以上，且不同种价态抗光折变元素随浓度增加对晶体光折变性能影响趋势不同，但同价态相近；引入具有孤对电子结构的铋离子与镁双掺，显著提升LN晶体在可见光波段的响应速度至13ms，保持较高的饱和衍射效率26%，光折变灵敏度达到163cm/J。利用提拉法、坩埚下降法生长了2英寸钼、镁、铋等掺杂LN晶体，尤其是在铋镁双掺铌酸锂晶体中，利用He-Cr固态激光器（442nm连续光）实现了刷新频率为30Hz的实时动态全息显示。本项目的实施，不仅掌握了铌酸锂快响应的调控技术，对更深层次地理解快响应的微观机制有着重要的理论指导意义，而且对拓展LN晶体的应用以及为开发小型化、便携式的实时动全息3D显示系统奠定了基础，这是无机晶体在全息显示应用中向前迈出的重要一步。