Abstract
In this paper, a simple experimental setup with an off-axis lenless Fourier arrangement without pre-magnification is built.
Based on common recording conditions of digital hologram, an improved recording condition is proposed, with which
higher resolution of reconstructed image can be obtained. By using a USAF test target as microscopic object, the digital
hologram is recorded by a "SensiCam" CCD sensor, which has an array of 1317×1035 pixels with 6.8μm x 6.8μm pixel
size. Based on Fresnel diffraction formula, the recorded hologram is reconstructed numerically. The lateral resolution of
2.76 μm without any pre-magnification has been demonstrated experimentally. The corresponding theoretical resolution
limitation is 2.39 μm. The result matches the theoretical prediction very well. In order to reconstruct three-dimensional
information, the recording parameters, such as the recording distance and the offset of the reference point source, are
determined accurately by using a synthetic method of an automatic phase correction procedure and a manual adjustment
process. Then, the accurate phase image can be obtained. The axial resolution better than 10nm has been also
demonstrated experimentally.
