Experimental study of vibration measurement based on laser frequency splitting principle
Yi Zhang, Zhibeng Deng, Yanmei Han, Yan Li, Shulian Zhang · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1998
A new method of measuring vibration is presented based on HeNe laser frequency splitting phenomenon and a series of experiments have been done. While a quartz crystal wedge which vibrates with the vibration of measured object is inserted to a HeNe laser cavity, each laser mode is split to two orthogonal laser modes with a frequency difference. The variation of the frequency difference is proportional to the displacement of the quartz wedge so that the frequency difference is modulated by vibration displacement signal. The vibration signal is demodulated to electrical signal through a photo-electric detector and signal processing circuit. A computer is used to adopt and analyze the vibration signal. By the system a 15nm resolution and 28nm repeatability of vibration amplitude are obtained. The method has good potential prospective to be applied in high resolution, low and middle frequency vibration measurement or random vibration measurement.