Abstract

A new kind of vibration analysis uses the three-dimensional graininess of light produced by a diffusing surface illuminated by a coherent beam of light as an indicator of the vibration mode. The image of the vibrating surface shows unblurred speckles in the nodal areas of the vibrating surface only. The resulting patterns resemble the classical Chladni sand patterns. Theoretical calculations of the average grain size of the light field are presented. These calculations allow an estimate to be made of the sensitivity of the vibration-analysis method reported. It is shown that the sensitivity can be adapted for vibration amplitudes in the range from 1 to 100 wavelengths. A description of the experimental setup is given. The results show good agreement between theory and experiment.

© 1971 Optical Society of America

Vibration-Analysis Studies Using Changes of Laser Speckle*†

Nils Fernelius and Conrad Tome
J. Opt. Soc. Am. 61(5) 566-572 (1971)

Noise Characteristics of Photographic Emulsions Used for Holography

Wai–Hon Lee and Milton O. Greer
J. Opt. Soc. Am. 61(3) 402-409 (1971)

Speckle Removal by a Slowly Moving Diffuser Associated with a Motionless Diffuser

Serge Lowenthal and Denis Joyeux
J. Opt. Soc. Am. 61(7) 847-851 (1971)

Properties of Granularity Wiener Spectra*

Stephen A. Benton and Richard E. Kronauer
J. Opt. Soc. Am. 61(4) 524-529 (1971)

Evanescent Waves and the Electromagnetic Field of a Moving Charged Particle*

R. Asby and E. Wolf
J. Opt. Soc. Am. 61(1) 52-59 (1971)