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In optical setups, especially those involving interferometry, the alignment of each component must be extremely accurate--precise down to a fraction of a wavelength--usually a few hundred nanometers. Even small vibrations or strain in the table on which the elements are set up might lead to complete failure of an experiment. Hence, one requires an extremely sturdy table which neither vibrates nor flexes, even under heavy loads. The surface of the table must also be quite flat, to allow precision optical mounts to make good contact with the table without rocking.
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