Studies Of Elastic Properties Of Solids With Dynamic Holography

Abstract

Double-exposure holographic interferometry in BTO photorefractive crystals using He-Ne laser (40 nIV ) light was demonstrated . The recording intensity, determined mainly by the reference beam, leads to a recording time of A,5 sec. This holographic interferometer can display continuously the interferograms on a TV-receiver. Experiments for the measurement of Young's modulus show the good reliability of the method and instrument. It is well known that double exposure holographic interferometry allows high precision measurements of small surface displacements produced in the analyzed real object by external force, When the analyzed object has a simple shape (for example, cantilevel beam), one can calculate static Young's modulus from measured displacement of the object's surface under definite external stress. In order to carry out automatization of the measuring process for different samples, it is necessary to record and reconstruct holograms several times per a minute, i.e. to obtain automatically double-exposure holographic interferograms. This can be done using photore-fractive electrooptic crystals, which are one of the best reversible media for the record-ing of dynamic hologram. We have used automatical holographic interferometer with a photo-refractive Bi12T1020 (BTO) crystal for experimental investigation of some solids, The BTO crystal is the most sensitive among photorefractive crystals for red recording light. Hence, it is possible to use a He-Ne laser (632,7 nm) as a coherent light source in the inteferometer.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.