提出一种基于傅里叶变换的频闪显微干涉测试方法,对微谐振器和微悬臂梁的离面运动进行测试研究。微结构受激励产生周期离面运动,单个运动周期分解成若干运动相位,利用频闪照明获得不同运动相位的干涉图像,通过傅里叶变换计算出各自的包裹相位,并利用时间轴相位展开提取出微结构的离面周期运动信息。与时间相移干涉法相比,该方法只需在单个运动相位下采集1幅干涉图像,减少了干涉图像采集的时间。对比实验结果表明,傅里叶干涉法的离面运动测量精度优于20nm.
A stroboscopic microscopic interferometry based on Fourier transform method(FTM) is put forward to measure the out-of-plane motion of micro-resonator and micro-cantilever. The periodic motion of microstructure is excited. The cycle of a periodic motion is divided into some motion phases. The interferogram sequence with different motion phases is collected via stroboscopic photography. FTM is applied to calculate the wrapped phase distribution of each interferogram,and the outof-plane motion characteristics are extracted from phase unwrapping curves of wrapped phase distribtions with different motion phase. Compared with temporal phase shifting interferometry,only one interferogram per motion phase is needed,and a lower acquisition time is obtained. Experiment study shows the measurement accuracy of out-of-plane motion is better than 20 nm.