Spatial filtering in digital holographic microscopy

An optical system based on digital holography suitable for microscopic inve stigations is described. A lensless digital hologram of the object under te st is recorded on a CCD faceplate. The reference point source and the objec t are equidistant from the CCD. The point source for the illumination of th e transparent microscopic object is located in another plane some millimetr es behind the object. For digital reconstruction of the wavefronts the Somm erfeld propagation relation is used. The particular recording arrangement a llows one to perform spatial filtering. Examples of amplitude filtering are presented.