Digital Holography for Shape Measurement of Transparent Microscopic Object

Digital holographic microscopy is very suitable for the measurement of the biological cells and tissue. An off-axis Fresnel digital holographic system with pre-magnification is built. The recording and numerical reconstruction of digital hologram is analyzed. Experimental investigations have been performed for a USAF test target. The accurate phase image is obtained by combining the automatic phase aberration compensation procedure proposed by T.Colomb with the manual adjustment method. The lateral resolution with better than 1 and the axial resolution of no larger than 10 nm have been achieved experimentally, which are coincident with the theoretical prediction very well. The results show that the recording of high quality digital hologram is critical important for quasi real-time phase reconstruction.