Design and Applications of a Holographic System for Crystal Growth Studies.
NAVAL RESEARCH LAB WASHINGTON D C
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Holography, with its unique depth of field and interferometric capabilities, is a powerful new tool for the study of crystal growth. This report describes the theory and practice of forming and reconstructing holograms as applied to the study of microscopic phenomena. It outlines the technical considerations involved in the design of a holographic laborabory and describes the type of experimental results which may be obtained. A holographic laboratory could employ several techniques of holographic microscopy, including holographic interferometry. In the holographic work at NRL an argon ion laser was used to record holograns of transparent organic analogs to solidifying metals. Special observation chambers were constructed to allow holographic recording of planar solidliquid interfaces, dendrites, floating crystals, and liquid inclusions in crystals. Crystal morphologies were measured by interferometric analysis of the reconstructed holograms. Crystal imperfections were shown to initiate surface relief features. A 2-percent anisotropy of the solidliquid surface energy was found to control anisotropic crystal growth. Author