基于新型弛豫铁电单晶的高频、宽带声光器件研究

Acousto-optical device is a very important part of modern photoelectron technology, which has been widely used in advanced scientific researches and many different industrial areas. Generally, the piezoelectric transducer of acousto-optical device is made of lithium niobate single crystal. However, due to the poor piezoelectric properties of lithium niobate single crystal, the performances of acousto-optical device could not be further improved. Recently, relaxor ferroelectric single crystal has been researched widely due to its superior piezoelectric and electromechanical properties. This project will carry out a systematic study on the scale effect of dielectric, piezoelectric and electromechanical properties for relaxor ferroelectric single crystal in high frequency and very high frequency range. Explore in depth the relationship between the micro domain structure and macro performance. Then, according to the application features of acousto-optical device, we will study the double-win mechanism between the relaxor ferroelectric single crystal and acousto-optical crystal. Finally, some high frequency and broadband acousto-optical devices will be designed and fabricated based on relaxor ferroelectric single crystals. The development of this project will provide theoretical and experimental basis for the application of relaxor ferroelectric single crystal in high performance acousto-optical device.

声光器件是现代光电子技术中非常重要的单元技术，在尖端科学研究和诸多工业产业中有着广泛的应用。传统的声光器件一般采用铌酸锂单晶制作压电换能器，但由于铌酸锂单晶本身的压电性能相对较低，阻碍了声光器件性能的进一步提高。近年来，新型弛豫铁电单晶引起了国际上的广泛关注，其压电性能和机电耦合系数都有极大提高，具有非常诱人的应用前景。本项目拟通过研究弛豫铁电单晶在高频、甚高频频率范围内介电、压电、机电耦合系数等性能的尺度效应，深入探索晶体内部微观畴结构的改变对于晶体宏观性能变化的作用机制；随后，结合声光器件的应用特点，研究弛豫铁电单晶和优质TeO2声光晶体之间的协调增益机制，研制出基于弛豫铁电单晶的高频、宽带声光器件，为开拓弛豫铁电单晶在声光器件中的应用提供理论和实验依据。

声光器件是现代光电子技术中非常重要的单元技术，在尖端科学研究和诸多工业产业中有着广泛的应用。声光器件主要由三个部分组成，即压电换能器、声光介质和键合层。从声光器件的基本结构上来看，声光器件包含两类功能材料——声光介质材料和压电材料。压电材料通过逆压电效应将电信号转换为超声波，进入到声光介质内部形成光栅。驰豫铁电单晶具有优异的压电性能和机电耦合性能，在超声换能器中得到了极大的应用。本项目以驰豫铁电单晶PIMNT在声光器件中的应用为目标，研究优化了PIMNT不同压电振动模式的性能及模式耦合特性，开展了两款基于PIMNT单晶的声光调制器的制备及性能研究。.通过对PIMNT的相结构研究，综合考虑晶体的温度稳定性和压电性能，确定PIMNT24/45.8/30.2组分处的晶体结构为MPB偏三方，具有优异的压电性能和温度稳定性，是制备高性能声光器件的理想材料。.通过对PIMNT压电振动模式的研究，确定横向长度伸缩模式压电性能的最优切型是沿 方向激励电场、沿 方向振动，即 ；.研究了PIMNT长条形压电振子的模式耦合特性，确定了振动模式与压电振子尺寸的依赖关系。.研制出两款基于PIMNT单晶的声光调制器，其中40MHz的声光调制器体的衍射光斑明显，体现出良好的声光效应，是典型的Bragg衍射。.本项目共发表论文5篇。