声表面波在压电晶体表面上的聚焦特性  

Focusing of surface acoustic wave on a piezoelectric crystal

作　　者：乔东海[1] 汪承灏[1] 王左卿[1] 

机构地区：[1]中国科学院声学研究所,北京100080

出　　处：《声学学报》2006年第4期350-354,共5页Acta Acustica

基　　金：国家自然科学基金资助项目(10134020)

摘　　要：研究了压电晶体表面上圆弧形叉指换能器产生的声表面波的聚焦现象。用作者提出的压电晶体表面激发的严格矢量场理论来计算会聚的表面波声场,取代了比较流行的源于光学的标量角谱理论。理论分析表明介质的各向异性对声束的会聚特性有很大的影响,如焦长和焦点附近声场的对称性。在实验中可以用光学暗场法来观察声表面波场的会聚。尽管各向异性介质或各向异性压电晶体上表面波声场的会聚都非常复杂,实验的结果和理论分析比较一致。This paper investigated the focusing phenomena of Surface Acoustic Wave （SAW） field generated by a circular-arc Inter-Digital Transducer （IDT） on a piezoelectric crystal. A rigorous vector field theory of surface excitation on the crystal developed by the authors was used to evaluate the convergent SAW field instead of the prevalent scalar angular spectrum one used in optics. The theoretical results show that the anisotropy of a medium has great impact on the focusing properties of the acoustic beams~ such as focal length and symmetrical distributions near the focus. A dark field method was used in experiment to observe the focusing of SAW field optically. Although the convergent phenomena of SAW field on the anisotropic media or piezoelectric crystals are very complicated. the experimental results were in agreement with those from the rigorous theory.

关 键 词：晶体表面 声表面波 压电晶体 聚焦特性 各向异性介质 叉指换能器 矢量场理论 角谱理论 会聚 圆弧形 

分 类 号：O421.5[理学—声学]