Microscope Holographic Double-Exposure Interferometer for the Analysis of Living Cells

A microscope holographic double-exposure interferometer based on photofractive crystals as reversible recording material for analysis of living cells is presented. The application of a cw-Nd:YAG-Laser in conjunction with a mechanical chopper system permits exposure times in millisecond range and sufficient delays between two exposures. In this way the repetition frequency of the holographic double-exposure interferometer is mainly limited by the CCD cameras acquisition rate that is applied for interferogram digitalization and provides the opportunity of dynamic changes of the sample. For the quantitative evaluation of the double-exposure interferogramms an additional spatial phase shift is applied. Results from the application of the interferometer on mechanically stimulated living human liver cells demonstrate the systems functionality.