Abstract-2.52 terahertz dual-axis reflection confocal scanning microscope

Qi Li, Yi Zhou, Yong-Fa Yang, and Guang-Hao Chen
https://www.osapublishing.org/josaa/abstract.cfm?uri=josaa-33-4-637

We present a dual-axis reflection confocal scanning microscope operating at 2.52 terahertz with axial resolution of 0.67 mm. The spatial resolution of the system was evaluated by utilizing the resolution test chart. Lateral resolution exceeded 0.314 mm, and the lengthwise resolution was over 0.353 mm. We introduced a 0.3 mm pinhole to improve the resolution. Targets such as the Chinese character “TAI” written on paper with a pencil and the metal letter “G” were scanned to test the imaging quality. To verify the imaging ability of the axial sections, two pairs of metal straps and a combinatorial metal ring were scanned, further revealing the satisfying 3D imaging capability.

© 2016 Optical Society of America

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Abstract-Support-domain constrained phase retrieval algorithms in terahertz in-line digital holography reconstruction of a nonisolated amplitude object

Jiaqi Hu, Qi Li, and Yi Zhou
https://www.osapublishing.org/ao/abstract.cfm?uri=ao-55-2-379

Phase retrieval algorithms applied to in-line digital holography reconstruction can weaken interference from the region outside the study target and an unstable light source, etc., by adopting the object-plane support domain constraint. Based on threshold segmentation and morphological filtering, a method to directly calculate the object-plane support domain is proposed in this paper. Combined with the above method, an improved support-domain constrained phase retrieval algorithm is presented. Then, imaging simulations and experiments on terahertz in-line digital holography reconstruction of nonisolated objects are conducted. The simulations study the influence of transmittance of the background plate, structural element of morphological filtering, etc., on the reconstruction effect of the improved algorithm without noise interference. Simulation and experiment results suggest that good reconstructed images can be obtained by this algorithm when transmittance of the background plate is greater than 0.90.

© 2016 Optical Society of America

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