In this paper, we present review and latest results obtained in the scope of terahertz holographic and other methods for phase retrieval in terahertz imaging. Not only accurate change of amplitude, but also rigorous phase retrieval is essential for precise calculation of optical parameters of the samples in terahertz range. Pulse terahertz holography introduced some years ago shows itself as perfect method for overall-object phase retrieval technique, but in the same time it allows measurement with low signal to noise that leads to less precise derivation of sample optical parameters. And certainly just point-by-point terahertz time-domain spectroscopy provides the most precise information of sample phase, but it is rather time consuming and has low spatial resolution as well. The other possible way assumes, in contrary to pulse terahertz holography and spectroscopy, using narrow-band continuous terahertz source, which tunability might also make the measurement process easier. And diffraction patterns registered with microbolometer array or any other terahertz intensity sensor placed at several different distances from the object and/or taken for several different terahertz frequencies are used for phase retrieval in this case. We present both numerical predictions and experimental results for the proposed methods, estimate the achievable spatial and other limits of the techniques and compare them to the others used in different spectral ranges.

Date Published: 24 September 2013
PDF: 7 pages
Proc. SPIE 8846, Terahertz Emitters, Receivers, and Applications IV, 88460S (24 September 2013); doi: 10.1117/12.2023918

Published in SPIE Proceedings Vol. 8846:
Terahertz Emitters, Receivers, and Applications IV
Manijeh Razeghi; Alexei N. Baranov; John M. Zavada, Editor(s)