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Updated: Aug 11, 2026
Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization
Published on: July 5, 2016
On-line surveillance of a dynamic process by a moving system based on pulsed digital holographic interferometry
Giancarlo Pedrini1, Igor Alexeenko, Wolfgang Osten
1Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, D-70569 Stuttgart, Germany. pedrini@ito.uni-stuttgart.de
Abstract:
A method based on pulsed digital holographic interferometry for the measurement of dynamic deformations of a surface by using a moving system is presented. The measuring system may move with a speed of several meters per minute and can measure deformation of the surface with an accuracy of better than 50 nm. The deformation is obtained by comparison of the wavefronts recorded at different times with different laser pulses produced by a Nd:YAG laser. The effect due to the movement of the measuring system is compensated for by digital processing of the different holograms. The system is well suited for on-line surveillance of a dynamic process such as laser welding and friction stir welding. Experimental results are presented, and the advantages of the method are discussed.
