The available techniques for the study of high frequency vibration using electronic speckle pattern interferometry (ESPI) are briefly surveyed. We concentrate on two methods in particular. The first is a straightforward approach in which a CCD camera is used having a frame rate of at least twice the highest vibration frequency so that the sampling criterion is satisfied. The images are processed and analysed off-line. Digital phase shifting can be also implemented for detailed fringe analysis. The second approach is time-averaged ESPI in which the Bessel fringe function can be analysed in real time by modulating the optical path difference in the interferometer. This can be done either by using a vibrating component or, as in the present work, by direct modulation of the laser wavelength at the frequency of the vibrating mode.

Date Published: 27 August 2003
PDF: 10 pages
Proc. SPIE 4876, Opto-Ireland 2002: Optics and Photonics Technologies and Applications, (27 August 2003); doi: 10.1117/12.464267

Published in SPIE Proceedings Vol. 4876:
Opto-Ireland 2002: Optics and Photonics Technologies and Applications
Vincent Toal; Norman Douglas McMillan; Gerard M. O'Connor; Eon O'Mongain; Austin F. Duke; John F. Donegan; James A. McLaughlin; Brian D. MacCraith; Werner J. Blau, Editor(s)