Laser scanning heterodyne-interferometer for micro-components

Laser Doppler vibrometry is a well-established technique for non-contact vibration measurement. The necessity to monitor the vibration of the whole surface rather than a single point leads to the appearance of laser scanning vibrometer, However, current scanning vibrometers are applied only to larger structures. Scanning vibrometer for micro-components whose feature size is in region of millimeters and microns is still under development, and no prominent achievement obtained until now. In this paper, a novel scanning laser vibrometry using the combination of acousto-optical deflector and telecentric lens for micro-components is described and the advantages and limitations of the system are discussed. A scanning vibrometer especially applicable to micro-components can be developed based on the technique described here. Experiments carried out on a diamond-cutting tool and high speed rotating rigid disc successfully demonstrate the principle of the system. (C) 2000 Elsevier Science B.V. All rights reserved.