SGER: Acoustic Memory in LiNbo3 and Domian Structures

提出了一项加强对周期极化铁电域中声波传播的科学认识和控制的研究计划。这些作者推测，声记忆效应可能与晶体内铁电磁畴壁的钉扎和驰豫有关。在这一点上，物理模型肯定是非常投机的，需要实验验证。这项拟议的研究的目的是验证在LiNbO_3中观察到的磁畴壁作为声记忆来源的钉扎和驰豫。另一个目标是发展对磁区壁在声波传播、反射和非线性效应中的作用的基本了解。此外，声波探测技术还可以为铁电领域的成像提供一种灵敏的非破坏性方法。具有周期结构的LiNbO_3和LiTaO_3等铁电晶体的应用为实现声表面波换能器、滤波器、延迟线、频率标准和模拟信号处理等新型声电子器件提供了可能性。由于具有较大的光学非线性，该晶体可用于电光调制器、参量振荡器和谐波发生器等器件。除了促进铁电材料的科学、工程和制造技术的发展外，这项研究还将在教育活动中得到应用，例如开发一门关于光电子材料、器件和应用的课程以及实际应用。

A research program to enhance the scientific knowledge and control of acoustic wave propagation in periodically poled ferroelectric domains is proposed. These authors speculated that the acoustic memory effect might be tied to the pinning and relaxation of ferroelectric domain walls within the crystal. The physical model is definitely very speculative at this point and requires experimental verification. The objective of this proposed research is to verify the pinning and relaxation of domain walls as a source of acoustic memory observed in LiNbO3. Another objective is to develop a basic understanding of the role of domain walls on acoustic wave propagation, reflection and nonlinear effects. Also, acoustic wave detection may provide a sensitive nondestructive method for imaging of ferroelectric domains.The application of ferroelectric crystals like LiNbO3 and LiTaO3 with periodic domain structures gives the possibility of realizing a new class of acoustoelectronic devices such as SAW transducers, filters, delay lines, frequency standards and analog signal processing. Because of the large optic nonlinearities, the crystals can be used in devices such as electro-optic modulators, parametric oscillators, and harmonic generators. Also, the piezoelectric properties allow application in the accelerometers, x-y positioners, ultrasonic cleaners, gas sensors, and ultrasonic wire bonders.In addition to advancing the development of the science, engineering, andmanufacturing technology in ferroelectric materials, the proposed research will find applications in educational activity such as in the development of a course on optoelectronic materials, devices and applications as well as practical applications.