金纳米棒各向异性吸收调控光致聚合物体全息光栅特性及应用

Doping nanospheres in photopolymer could enhance the refractive index modulation, resist polymerization-induced shrinkage and improve polarization characteristics. Due to their simple shape, the nanospheres have a limited effect on photopolymer. The enhancements of holographic performance by nanospheres are rather limited. In this project we propose a method by doping nanorods instead of nanospheres in photopolymer to realize anisotropic absorption control on 3-D volume holographic gratings, based on the transverse surface plasmon resonance and longitudinal surface plasmon resonance of the nanorods. The unique optical characteristics of nanorods, such as super-resolution subwavelength modulation of wave front, polarized excitation and localized enhancement, are investigated to enhance the holographic material’s sensitivity to the multi-dimensional optical field. The dynamic grating formation is analyzed theoretically and experimentally with both the absorption grating of nanorods and refractive index grating of photopolymer during the holographic exposure. High performance gold nanorods doped photopolymer will be synthesized. Based on the proposed mechanism, the diffraction efficiency could be enlarged, the working wavelength band could be expanded, and the holographic exposure threshold could be reduced. The hybrid polarization, angle and wavelength multiplexing could be applied for recording multiple volume holographic gratings. The multiplexing density could be increased by one or two orders. With the developed material, the super-high density data storage and super-high resolution display system with the 3-D image size of 1920×1080×500 pixels will be demonstrated.

在光致聚合物材料中掺入纳米球状颗粒可以增强折射率调制度、偏振响应和抗收缩性能等，但球状颗粒由于作用机理单一，作用效能有限。本项目首次提出掺入金纳米棒状颗粒，基于其独特的横向和纵向表面等离子体共振效应，实现对三维体全息光栅进行各向异性吸收调控。首先研究金纳米棒亚波长超分辨光场调控、局域光场增强、波长选择激发和偏振选择激发行为，有效增强全息介质对多维光场参量的响应灵敏度。通过理论和实验分析全息曝光时金纳米棒形成的各向异性吸收调制光栅和聚合物形成的折射率调制光栅的动态形成过程，建立各向异性混合体全息光栅模型。制备高性能金纳米棒掺杂光致聚合物介质，基于新机理有效增强衍射性能、拓展全息曝光光谱范围和降低曝光阈值，实现偏振、角度和波长的密集多维复用记录三维体全息光栅，将复用密度提高一到两个数量级。构建出新型超大容量记录和超高分辨率全息显示光学系统，最终三维显示分辨率达到1920×1080×500像素。

本项目基于金纳米棒会被电磁波激发出表面等离子体激元共振的独特光学性质，提出了一种掺杂粒子形状的改进方法，使光致聚合物介质能够耦合记录光栅光波长，从而提升掺杂纳米复合材料的全息光学性能。通过理论和实验分析了金纳米棒形成的各向异性吸收调制光栅和聚合物形成的折射率调制光栅的动态形成过程，提出了一种利用掺杂光致聚合物的吸收光谱定量化分析光致聚合物合成过程的方法。制备了高性能金纳米棒掺杂光致聚合物介质，实现了偏振、角度和波长的密集多维复用，有效提高了复用密度，并进一步探索了该技术在超表面偏振和复振幅调制中的响应特性。搭建了多波长复用同轴全息光路系统，基于聚合物材料制备了全彩色反射式体全息图。基于体全息相关技术和高性能计算全息光学技术，实现了高分辨率彩色三维显示。基于本项目相关成果在Advances in Optics and Photonics, Optics Letters, Applied Physics Letters等期刊发表SCI论文15篇，培养博士后2名，博士研究生6名，硕士研究生3名。基本本项目相关成果，课题组已获得了两项国家级项目的支持，成果可应用于高性能光栅器件、三维动态全息显示系统、虚拟现实近眼显示系统和高密度纳米光存储等领域。