On Accuracy Of Holographic Shape Measurement Method With Spherical Wave Illumination

This paper presents the study on the accuracy of topography measurement of high numerical aperture focusing microobjects in digital holographic microscope setup. The system works in reflective configuration with spherical wave illumination. For numerical reconstruction of topography of high NA focusing microobjects we are using two algorithms: Thin Element Approximation (TEA) and Spherical Local Ray Approximation (SLRA). In this paper we show comparison of the accuracy of topography reconstruction results using these algorithms. We show superiority of SLRA method. However, to obtain accurate results two experimental conditions have to be determined: the position of point source (PS) and imaging reference plane (IRP). Therefore we simulate the effect of point source (PS) and imaging reference plane (IRP) position on the accuracy of shape calculation. Moreover we evaluate accuracy of determination of location of PS and IRP and finally present measurement result of microlens object.