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Proceedings Paper

THz optical design considerations and optimization for medical imaging applications
Author(s): Shijun Sung; James Garritano; Neha Bajwa; Bryan Nowroozi; Nuria Llombart; Warren Grundfest; Zachary D. Taylor
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Paper Abstract

THz imaging system design will play an important role making possible imaging of targets with arbitrary properties and geometries. This study discusses design consideration and imaging performance optimization techniques in THz quasioptical imaging system optics. Analysis of field and polarization distortion by off-axis parabolic (OAP) mirrors in THz imaging optics shows how distortions are carried in a series of mirrors while guiding the THz beam. While distortions of the beam profile by individual mirrors are not significant, these effects are compounded by a series of mirrors in antisymmetric orientation. It is shown that symmetric orientation of the OAP mirror effectively cancels this distortion to recover the original beam profile. Additionally, symmetric orientation can correct for some geometrical off-focusing due to misalignment. We also demonstrate an alternative method to test for overall system optics alignment by investigating the imaging performance of the tilted target plane. Asymmetric signal profile as a function of the target plane’s tilt angle indicates when one or more imaging components are misaligned, giving a preferred tilt direction. Such analysis can offer additional insight into often elusive source device misalignment at an integrated system. Imaging plane tilting characteristics are representative of a 3-D modulation transfer function of the imaging system. A symmetric tilted plane is preferred to optimize imaging performance.

Paper Details

Date Published: 5 September 2014
PDF: 5 pages
Proc. SPIE 9199, Terahertz Emitters, Receivers, and Applications V, 91990S (5 September 2014); doi: 10.1117/12.2062403
Show Author Affiliations
Shijun Sung, Univ. of California, Los Angeles (United States)
James Garritano, Univ. of California, Los Angeles (United States)
Neha Bajwa, Univ. of California, Los Angeles (United States)
Bryan Nowroozi, Univ. of California, Los Angeles (United States)
Nuria Llombart, Technische Univ. Delft (Netherlands)
Warren Grundfest, Univ. of California, Los Angeles (United States)
Zachary D. Taylor, Univ. of California, Los Angeles (United States)

Published in SPIE Proceedings Vol. 9199:
Terahertz Emitters, Receivers, and Applications V
Manijeh Razeghi; Alexei N. Baranov; John M. Zavada; Dimitris Pavlidis, Editor(s)

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