Vibration analysis by holography

Abstract

Contents 1. Introduction . 2. Holography in general . 2.1. Theory , 2.2. General holographic techniques . 2.3. Holographic recording media . 2.4. Techniques for maximum light utilization 3.1. Theory , 3.2. The basic stroboscopic method and its uses . 3.3. Live and frozen fringe techniques. 3.4. Strobing techniques . 3.5. Advantages of the stroboscopic method 3.6. Disadvantages of the stroboscopic method 4.1. Theory .4.2. Advantages and disadvantages of the time-averaged method 4.3. Modifications . 4.4. An application of time-averaged holography. 5 . Alterations in sensitivity, and related methods . 5.1. Methods for increasing sensitivity . 5.2. Methods for reducing sensitivity . 5.3. Related methods of vibration analysis . 5.4. Conclusion..

Evaluation of surface acoustic waves on the human skin using quasi-time-averaged digital Fresnel holograms

“…(14), when taking into account the illumination conditions [Eq. (6)]. The amplitude is included in the range 60-160 nm.…”

“…A part of this huge amount of literature is devoted to vibration analysis. Historically, vibration analysis with optical holographic techniques started with the works of Powell and Stetson [3,4], followed by those of Watrasie and Spicer [5], Fryer [6], and Lokberg [7], which first established the principle of time averaging and the possibility of studying vibrations by using holography. The first applications were described, showing a large variety of possibilities: tympanic investigations [8], vibrations of plates [9], mode discrimination [10], or study of loudspeaker membranes [11].…”