基于激光外差与线性调频技术复合检测电致伸缩系数方法研究

Electrostriction coefficient can reflect the inherent properties of piezoelectric material and is the important parameter to measure its electrostrictive characteristic. The electrostriction coefficient can be accurately measured by using small length variation based on inverse piezoelectric effect. The conventional optical measuring method based on direct detection of light intensity distribution to obtain small length variation, is restricted by light source power stability and environmental perturbation, and can not reach high measuring accuracy. This project uses the combination of laser heterodyne technology with linear frequency modulation technology to load small length variation to the heterodyne signal frequency. By researching on the theoretical models of heterodyne signal for measuring small length variation, and the relationship between heterodyne signal frequency and electrostriction coefficient, the direct intensity detection can be replaced by heterodyne signal frequency detection, the effects of light source power stability and environmental perturbation can be removed. The measuring accuracy of electrostriction coefficient can be further improved by using the frequency demodulation to obtain small length variation. Based on this, the theoretical simulation and experimental research on electrostriction coefficient of testing sample will be acted; the anticipated results will own certain scientific significance and research value for the analysis of electrostrictive characteristics of piezoelectric material.

电致伸缩系数反映了压电材料本身固有属性，是衡量电致伸缩特性重要参数之一。基于逆压电效应，准确测量微小长度变化量可实现电致伸缩系数高精度测量。现有光学测量方法基于直接检测光强分布获取微小长度变化量，但受光源功率稳定性和环境扰动制约，测量精度不高。本项目采用激光外差技术融合线性调频技术，加载微小长度变化量于外差信号频率中。重点研究测量微小长度变化量的外差信号理论模型及外差信号频率与电致伸缩系数间数学模型，实现外差信号频率检测取代直接强度检测，消除光源稳定性与环境扰动影响，同时采用频率解调获取微小长度变化量，进一步提高电致伸缩系数测量精度。以此为依据，通过理论仿真辅以实验研究待测样品电致伸缩系数，预期成果对分析压电材料电致伸缩特性具有一定科学意义和研究价值。

电致伸缩系数反映了压电晶体材料本身的固有属性，是衡量压电材料电致伸缩特性重要参数之一。关于压电晶体材料电致伸缩特性的研究是国内外基础材料研究中的热门课题。. 本项目基于逆压电效应，准确测量微小长度变化量可实现电致伸缩系数高精度测量。现有光学测量方法基于直接检测光强分布获取微小长度变化量，但受光源功率稳定性和环境扰动制约，测量精度不高。本项目采用激光外差技术融合线性调频技术，加载微小长度变化量于外差信号频率中。重点研究了测量微小长度变化量的外差信号理论模型及外差信号频率与电致伸缩系数间数学模型，实现外差信号频率检测取代直接强度检测，消除光源稳定性与环境扰动影响，同时采用频率解调获取微小长度变化量，进一步提高电致伸缩系数测量精度。以此为依据，通过理论仿真研究待测PZT样品电致伸缩系数，测量相对误差仅为0.04%，同现有技术相比精度提高了两个量级。. 将激光外差技术与线性调频技术有机结合，优势互补，会明显提高压电晶体材料电致伸缩系数的测量精度。目前，关于激光外差技术与线性调频技术相结合用于高精度测量电致伸缩系数的研究尚未见报道。本课题的研究成果经过方案拓展，可以用于测量与位移或者距离变化量有关的物理参量，为其它高精度测量技术领域提供必要的理论参考，因此具有一定的科学意义。