Phase-contrast microscopy by in-line phase-shifting digital holography: shape measurement of a titanium pattern with nanometer axial resolution

Abstract

Precision phase-contrast imaging has been achieved with in-line phase-shifting digital holographic microscopy. The complex amplitude of the object field on the charge-coupled device plane is measured by the phase-shifting method with a self-calibration algorithm, and the magnified object image is reconstructed with a plane wave expansion method. The phase fluctuation in the blank image without sample is 1.30 deg and the three-dimensional shape of a titanium phase test pattern is measured with an accuracy of 5.51 nm (corresponding to the phase resolution of 3.63 deg), which are better than those of off-axis systems. (c) 2007 Society of Photo-Optical Instrumentation Engineers.