THz干涉测量用于障碍物后振动传感的研究

为探索THz干涉技术用于障碍物后振动传感的可行性,采用工作波长214.58 μm （对应频率约1.4 THz）的CO2激光器泵浦气体太赫兹源搭建了一套基于迈克尔逊干涉仪结构的THz干涉测量装置,实验研究了薄纸板遮挡后敲击目标镜产生的微小振动,利用相位分析法和频谱分析法对振动干涉信号进行处理,得到了振动位移随时间的变化以及不同时段振动频率的分布情况,测得的峰峰值振幅最小为7.98 μm,最大为17.54 μm,振动峰值速度为2.7 mm/s,振动频率最小21 Hz,最大58 Hz.研究结果表明THz干涉测量技术能有效克服传统振动传感技术无法穿透障碍物的缺点,是一种简便有效的障碍物后振动传感的新型手段,预示了THz技术在振动检测相关领域的广阔应用前景.

Study of Vibration Sensing Behind Barriers by Terahertz Interferometry

In order to explore the feasibility of vibration sensing behind barriers by terahertz interferometry,a terahertz interferometer was built based on a Michelson interferometer and using 214.58 μm CO2 laser pumping gas THz source.Small vibrations behind a thin cardboard caused by knocking a target mirror was measured by the terahertz interferometer .With some data processing techniques such as phase analysis and spectrum analysis,vibration time-histories and time-frequence distribution were resolved.The maximum of measured peak-peak amplitude is 17.54 μm and the minimum is 7.98 μm.The calculated peak velocity is about 2.7 mm/s.The maximum and minimum of vibration frequence are 58 Hz and 21 Hz,respectively.The results show that terahertz interferometry is a convenient novel technique that senses vibrations behind barriers,and can effectively overcome disadvantages of conventional vibration sensors.