Inspection of micrometric size semitransparent biological samples using a transmission digital holographic interferometer

摘要

A new configuration of a transmission digital holographic interferometer to observe micro scale samples is presented. The optical system uses high magnification to analyze the phase of semitransparent biological samples in order to measure their size. As proof of principle some previously characterized pollen grains are placed in the object's beam path and magnified by projection on the neutral phase screen whose image is conveyed on the camera sensor and thus is used to retrieve the optical phase that is related to the size of each particle. As validation fluorescence and transmission images from a confocal microscope are used to compare the phase intensity retrieved with the interferometric system. Results show a direct relation between the pollen size and the resulting phase magnitude after geometrical processing with the advantage of having a micrometric measurement with a simple optical set up.