Extending speckle pattern interferometry for use on a microscopic scale

Design, manufacturing and test of microcomponents generate new challenges for measurement techniques in general. The non-contacting operation of optical metrology makes it attractive to solve the task of measuring geometric quantities of microparts. So far, speckle pattern interferometry (ESPI) is well established as a measuring tool for analyzing deformation, vibration and strain on a macroscopic level. This paper deals with possibilities and application limits of ESPI in the case of scaling down the object size below one millimeter. Theoretical considerations are shown together with experimental verification.