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.

Date Published: 20 May 2009
PDF: 6 pages
Proc. SPIE 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 72833P (20 May 2009); doi: 10.1117/12.828783

Published in SPIE Proceedings Vol. 7283:
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; James C. Wyant; Robert A. Smythe; Hexin Wang, Editor(s)