声子晶体点缺陷模式及其高分辨传感特性研究

发布时间：2018-05-24 23:01

本文选题：声子晶体 + 点缺陷　；参考：《中国科学院长春光学精密机械与物理研究所》2016年博士论文

【摘要】：声子晶体缺陷态模式由于能量局域化效应可形成高品质因数(Q值)声波谐振器,为高分辨率声波质量传感器的实现提供了新的途径。本论文围绕声子晶体点缺陷模式的关键损耗因素、质量传感特性以及面向应用的声子晶体结构设计等问题展开了理论和实验研究。主要内容及结论如下:1.在点缺陷模式仿真分析的基础上,给出了基于激光外差干涉测振仪的模式振型精确测试和识别的方法,为点缺陷模式损耗分析和质量灵敏度分析奠定了基础;2.基于相干共振的模型分析了模式频率响应曲线非对称现象,提出了一种精确拟合模式响应曲线而获得各模式准确的Q值的方法,解决了在非对称条件下采用3d B法获得模式Q值较大误差的问题;3.分析了各点缺陷模式的振型与模式Q值之间的关系,建立了模式主要损耗模型,得出谐振器表面压电薄膜Al N材料损耗为主要损耗源;4.基于DDS(直接数字频率合成)与幅相检测集成芯片设计制作了小型化、数字化的实时质量传感检测系统。采用双模式测量法实现了传感器温度补偿,该方法利用各点缺陷模式质量灵敏度差异,在检测过程中同时测量两各模式的频率偏移,实现温度质量解耦。补偿后模式频率分辨率达到0.25 Hz,对应的质量分辨率为46 pg;5.针对传感实验中孔式声子晶体结构质量加载和液相处理较困难的问题,提出了管柱式平板声子晶体结构。基于数值仿真分析了其禁带产生的机理以及禁带随结构的变化规律。结果显示,管柱式结构增强了声波的多重散射,使得其产生禁带所需的柱高仅为传统圆柱式结构柱高的50%,从而增强了声子晶体结构的稳定性,降低加工成本。此外,双管柱式结构有利于禁带拓宽,在相同填充率下其禁带宽度是单管柱式结构的2倍以上。本论文为声子晶体点缺陷模式应用于高分辨率声波质量传感提供了理论和实验基础。
[Abstract]:Due to the energy localization effect, the phonon crystal defect mode can form a high quality factor / Q) acoustic resonator, which provides a new way for the realization of high resolution acoustic mass sensor. In this paper, theoretical and experimental studies have been carried out on the key loss factors of the point defect mode of phonon crystals, the characteristics of mass sensing and the structure design of phonon crystals for application. The main contents and conclusions are as follows: 1. On the basis of the simulation analysis of point defect mode, the method of accurate mode measurement and identification based on laser heterodyne interferometer is presented, which lays a foundation for point defect mode loss analysis and mass sensitivity analysis. Based on the coherent resonance model, the asymmetric phenomenon of the frequency response curve of the mode is analyzed, and a method of accurately fitting the response curve of the mode to obtain the accurate Q value of each mode is proposed. The problem of large error of mode Q value obtained by 3D B method under asymmetric condition is solved. The relationship between mode and mode Q is analyzed. The main loss model of mode is established, and the loss of Al N film on the surface of resonator is obtained as the main loss source. Based on DDS (Direct Digital Frequency Synthesis) and amplitude-phase detection integrated chip, a miniaturized and digitized real-time quality sensing system is designed. The temperature compensation of the sensor is realized by using the dual-mode measurement method. In this method, the frequency offset of the two modes is measured simultaneously in the detection process, and the temperature quality decoupling is realized by using the difference in the quality sensitivity of each defect mode. The frequency resolution of the compensated mode is 0.25 Hz, and the corresponding quality resolution is 46 PG / m 5. Aiming at the difficulty of mass loading and liquid phase processing of the porous phonon crystal structure in the sensing experiment, a tubular flat plate phonon crystal structure is proposed. Based on numerical simulation, the mechanism of band gap and its variation with structure are analyzed. The results show that the multi-scattering of acoustic waves is enhanced by the tubular structure, and the column height required to produce the band gap is only 50 the height of the column height of the traditional cylindrical structure. Thus, the stability of the phonon crystal structure is enhanced and the processing cost is reduced. In addition, the band-gap width of the double-tube column structure is more than 2 times that of the single-tube column structure under the same filling ratio. This paper provides a theoretical and experimental basis for the application of point defect mode of phonon crystals to high resolution acoustic mass sensing.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O735;TP212

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