Abstract

We demonstrate a noniterative adaptive reconstruction technique to significantly improve the imaging performance of sparse terahertz arrays employing single-cycle pulses. Grating lobe artifacts are suppressed by an adaptive weighting factor derived from the temporal coherence of signals from neighboring array elements. Image quality is further improved by a second weighting factor based on the spatial coherence of signals across the entire array. Experiments are performed with a synthetic aperture two-dimensional sparse array of 56×56 elements. Our reconstruction technique suppresses artifacts by 30dB.

© 2010 Optical Society of America

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  1. W. L. Chan, J. Deibel, and D. M. Mittleman, Rep. Prog. Phys. 70, 1325 (2007).
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    [CrossRef] [PubMed]
  8. Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
    [CrossRef]
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    [CrossRef]
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    [CrossRef]
  11. J. W. Goodman, Statistical Optics (Wiley-Interscience, 1985).
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    [CrossRef] [PubMed]
  13. Z. Zhang and T. Buma, Opt. Express 17, 17812 (2009).
    [CrossRef] [PubMed]

2009 (4)

2007 (2)

Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
[CrossRef]

W. L. Chan, J. Deibel, and D. M. Mittleman, Rep. Prog. Phys. 70, 1325 (2007).
[CrossRef]

2004 (3)

T. Buma and T. B. Norris, Appl. Phys. Lett. 84, 2196 (2004).
[CrossRef]

M.-L. Li, W. J. Guan, and P.-C. Li, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 51, 63 (2004).
[CrossRef] [PubMed]

J. O’Hara and D. Grischkowsky, J. Opt. Soc. Am. B 21, 1178 (2004).
[CrossRef]

2002 (1)

A. Austeng and S. Holm, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 49, 1073 (2002).
[CrossRef] [PubMed]

1998 (2)

C. H. Frazier and W. D. O’Brien, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 196 (1998).
[CrossRef]

J. L. Schwartz and B. D. Steinberg, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 376 (1998).
[CrossRef]

Austeng, A.

A. Austeng and S. Holm, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 49, 1073 (2002).
[CrossRef] [PubMed]

Bao, Z.

Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
[CrossRef]

Barat, R. B.

Bolivar, P. H.

Buma, T.

Z. Zhang and T. Buma, Opt. Express 17, 17812 (2009).
[CrossRef] [PubMed]

T. Buma and T. B. Norris, Appl. Phys. Lett. 84, 2196 (2004).
[CrossRef]

Chan, W. L.

W. L. Chan, J. Deibel, and D. M. Mittleman, Rep. Prog. Phys. 70, 1325 (2007).
[CrossRef]

Deibel, J.

W. L. Chan, J. Deibel, and D. M. Mittleman, Rep. Prog. Phys. 70, 1325 (2007).
[CrossRef]

Federici, J. F.

Frazier, C. H.

C. H. Frazier and W. D. O’Brien, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 196 (1998).
[CrossRef]

Friederich, F.

Gary, D. E.

Goodman, J. W.

J. W. Goodman, Statistical Optics (Wiley-Interscience, 1985).

Grischkowsky, D.

Guan, W. J.

M.-L. Li, W. J. Guan, and P.-C. Li, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 51, 63 (2004).
[CrossRef] [PubMed]

Hangyo, M.

H. Kitahara, M. Tani, and M. Hangyo, Appl. Phys. Lett. 94, 09119 (2009).
[CrossRef]

Holm, S.

A. Austeng and S. Holm, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 49, 1073 (2002).
[CrossRef] [PubMed]

Kitahara, H.

H. Kitahara, M. Tani, and M. Hangyo, Appl. Phys. Lett. 94, 09119 (2009).
[CrossRef]

Li, M.-L.

M.-L. Li, W. J. Guan, and P.-C. Li, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 51, 63 (2004).
[CrossRef] [PubMed]

Li, P.-C.

M.-L. Li, W. J. Guan, and P.-C. Li, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 51, 63 (2004).
[CrossRef] [PubMed]

Liu, Z.

Michalopoulou, Z.-H.

Mittleman, D. M.

W. L. Chan, J. Deibel, and D. M. Mittleman, Rep. Prog. Phys. 70, 1325 (2007).
[CrossRef]

Norris, T. B.

T. Buma and T. B. Norris, Appl. Phys. Lett. 84, 2196 (2004).
[CrossRef]

O’Brien, W. D.

C. H. Frazier and W. D. O’Brien, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 196 (1998).
[CrossRef]

O’Hara, J.

Roskos, H. G.

Schwartz, J. L.

J. L. Schwartz and B. D. Steinberg, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 376 (1998).
[CrossRef]

Spickermann, G.

Steinberg, B. D.

J. L. Schwartz and B. D. Steinberg, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 376 (1998).
[CrossRef]

Su, K.

Tani, M.

H. Kitahara, M. Tani, and M. Hangyo, Appl. Phys. Lett. 94, 09119 (2009).
[CrossRef]

Wang, Q.

Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
[CrossRef]

Wu, R.

Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
[CrossRef]

Xing, M.

Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
[CrossRef]

Zhang, Z.

Appl. Opt. (1)

Appl. Phys. Lett. (2)

H. Kitahara, M. Tani, and M. Hangyo, Appl. Phys. Lett. 94, 09119 (2009).
[CrossRef]

T. Buma and T. B. Norris, Appl. Phys. Lett. 84, 2196 (2004).
[CrossRef]

IEEE Trans. Geosci. Remote Sens. (1)

Q. Wang, R. Wu, M. Xing, and Z. Bao, IEEE Trans. Geosci. Remote Sens. 4, 480 (2007).
[CrossRef]

IEEE Trans. Ultrason. Ferroelectr. Freq. Control (4)

C. H. Frazier and W. D. O’Brien, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 196 (1998).
[CrossRef]

J. L. Schwartz and B. D. Steinberg, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 45, 376 (1998).
[CrossRef]

A. Austeng and S. Holm, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 49, 1073 (2002).
[CrossRef] [PubMed]

M.-L. Li, W. J. Guan, and P.-C. Li, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 51, 63 (2004).
[CrossRef] [PubMed]

J. Opt. Soc. Am. B (1)

Opt. Express (1)

Opt. Lett. (1)

Rep. Prog. Phys. (1)

W. L. Chan, J. Deibel, and D. M. Mittleman, Rep. Prog. Phys. 70, 1325 (2007).
[CrossRef]

Other (1)

J. W. Goodman, Statistical Optics (Wiley-Interscience, 1985).

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Figures (4)

Fig. 1
Fig. 1

(a) Geometry of a 1D sparse array. (b) Simulated reconstruction with single-cycle THz pulses. (c) Experimental setup for synthesizing a THz sparse array.

Fig. 2
Fig. 2

Images of wire targets processed with (a) SAFT, (b) SAFT + IF , (c) SAFT + CF , (d) SAFT + IF + CF . All images have a 20 dB scale. (e) Beam patterns using SAFT (gray dash), SAFT + IF (solid gray), SAFT + CF (black dash), and SAFT + CF + IF (solid black).

Fig. 3
Fig. 3

En face images reconstructed with (a) SAFT, (b) SAFT + CF , (c) SAFT + CF + IF , (d) no processing. All images have a 40 dB scale ( 72 × 72 mm area).

Fig. 4
Fig. 4

Central row of images formed with (a) SAFT, (b) SAFT + CF , (c) SAFT + CF + IF , (d) no processing.

Equations (3)

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γ ( x m , x m 1 ; k ) = 2 n = 0 N 1 u m * ( n ) u m 1 ( n + k ) n = 0 N 1 ( | u m ( n ) | 2 + | u m 1 ( n ) | 2 ) ,
γ ( x m , x m + 1 ; k ) = 2 n = 0 N 1 u m * ( n ) u m + 1 ( n + k ) n = 0 N 1 ( | u m ( n ) | 2 + | u m + 1 ( n ) | 2 ) .
IF m = 2 | k = N 2 ( N 2 ) 1 γ * ( x m , x m 1 ; k ) γ ( x m , x m + 1 ; k ) | k = N 2 ( N 2 ) 1 ( | γ ( x m , x m 1 ; k ) | 2 + | γ ( x m , x m + 1 ; k ) | 2 ) .

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