
Proceedings Paper
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Paper Abstract
We present a scanning THz-camera with active illumination. Three different fully electronic transceiving techniques
are evaluated: The first employs a commercial 230-320GHz frequency-modulated continuous-wave system
with a harmonic mixing detector. Its bandwidth allows a ranging resolution in the mm-range. The second one
is based on heterodyne detection operating at 645GHz with sub-harmonic mixer and provides a dynamic range
beyond 100 dB. Like in the first system, we employ local illumination (THz beam focused on observed pixel).
The third one equals the second one, but utilizes global illumination of the scene. In all cases, the scanning optics
consists of a Cassegrainian telescope with a primary mirror diameter of 23 cm and a scanning mirror, which is
spinning about a slightly tilted axis which itself is slowly rotated in a perpendicular direction to provide the second
scan-dimension. With a typical distance of 0.5m between the scanning mirror and the object plane, the field
of view covers several 100cm2. While the fast mirror axis spins with about 660RPM, the slow axis turns with
at least 1 deg. per second and the data acquisition samples about 40000 points for each THz-image. Single-pixel
detectors are used; the frame acquisition time is below 10 s. The development of a video-rate multi-pixel imager
with up to 32 sub-harmonic mixers as detectors is in progress.
Paper Details
Date Published: 30 April 2009
PDF: 11 pages
Proc. SPIE 7311, Terahertz Physics, Devices, and Systems III: Advanced Applications in Industry and Defense, 73110O (30 April 2009); doi: 10.1117/12.817925
Published in SPIE Proceedings Vol. 7311:
Terahertz Physics, Devices, and Systems III: Advanced Applications in Industry and Defense
Mehdi Anwar; Nibir K. Dhar; Thomas W. Crowe, Editor(s)
PDF: 11 pages
Proc. SPIE 7311, Terahertz Physics, Devices, and Systems III: Advanced Applications in Industry and Defense, 73110O (30 April 2009); doi: 10.1117/12.817925
Show Author Affiliations
W. von Spiegel, Johann Wolfgang Goethe-Univ. Frankfurt am Main (Germany)
C. am Weg, Johann Wolfgang Goethe-Univ. Frankfurt am Main (Germany)
R. Henneberger, Radiometer Physics GmbH (Germany)
C. am Weg, Johann Wolfgang Goethe-Univ. Frankfurt am Main (Germany)
R. Henneberger, Radiometer Physics GmbH (Germany)
R. Zimmermann, Radiometer Physics GmbH (Germany)
T. Loeffler, SynView GmbH (Germany)
H. G. Roskos, Johann Wolfgang Goethe-Univ. Frankfurt am Main (Germany)
T. Loeffler, SynView GmbH (Germany)
H. G. Roskos, Johann Wolfgang Goethe-Univ. Frankfurt am Main (Germany)
Published in SPIE Proceedings Vol. 7311:
Terahertz Physics, Devices, and Systems III: Advanced Applications in Industry and Defense
Mehdi Anwar; Nibir K. Dhar; Thomas W. Crowe, Editor(s)
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