Abstract-Comparison of digital beamforming algorithms for 3-D terahertz imaging with sparse multistatic line arrays

Bessem Baccouche, Patrick Agostini, Falco Schneider, Wolfgang Sauer-Greff, Ralph Urbansky,  Fabian Friederich

https://www.adv-radio-sci.net/15/283/2017/

In this contribution we compare the back-projection algorithm with our recently developed modified range migration algorithm for 3-D terahertz imaging using sparse multistatic line arrays. A 2-D planar sampling scheme is generated using the array's aperture in combination with an orthogonal synthetic aperture obtained through linear movement of the object under test. A stepped frequency continuous wave signal modulation is used for range focusing. Comparisons of the focusing quality show that results using the modified range migration algorithm reflect these of the back-projection algorithm except for some degradation along the array's axis due to the operation in the array's near-field. Nevertheless the highest computational efficiency is obtained from the modified range migration algorithm, which is better than the numerically optimized version of the back-projection algorithm. Measurements have been performed by using an imaging system operating in the W frequency band to verify the theoretical results.

Abstract- Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser

Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser

J. Keeley, P. Dean, A. Valavanis, K. Bertling, Y. L. Lim, R. Alhathlool, T. Taimre, L. H. Li, D. Indjin, A. D. Rakić, E. H. Linfield, and A. G. Davies  »View Author Affiliations

http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-40-6-994

Optics Letters, Vol. 40, Issue 6, pp. 994-997 (2015)
http://dx.doi.org/10.1364/OL.40.000994

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We demonstrate coherent three-dimensional terahertz imaging by frequency modulation of a quantum cascade laser in a compact and experimentally simple self-mixing scheme. Through this approach, we can realize significantly faster acquisition rates compared to previous schemes employing longitudinal mechanical scanning of a sample. We achieve a depth resolution of better than 0.1 μm with a power noise spectral density below −50  dB/Hz, for a sampling time of 10  ms/pixel.

© 2015 Optical Society of America