Abstract

We propose a method for high-speed terahertz spectroscopic imaging that is based on electro-optic sampling with a noncollinear geometry of the THz beam and probe laser beam and has a multistep mirror in the path of the probe beam. We made an imaging system that operates in the over 2.0-THz range and enables the sample region corresponding to a (28 × 28)-pixel area on the sensor to be imaged with a spatial resolution of 1.07 mm and a frequency resolution of 0.079 THz. We also show how the proposed method might be extended for faster THz spectroscopic imaging.

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  1. D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
    [CrossRef]
  2. B. B. Hu and M. C. Nuss, “Imaging with terahertz waves,” Opt. Lett. 20(16), 1716–1718 (1995).
    [CrossRef] [PubMed]
  3. D. A. Zimdars, “Fiber-pigtailed terahertz time domain spectroscopy instrumentation for package inspection and security imaging,” Proc. SPIE 5070, 108–116 (2003).
    [CrossRef]
  4. V. P. Wallace, A. J. Fitzgerald, B. C. Cole, R. J. Pye, and D. D. Arnone, “Biomedical applications of THz imaging,” Microwave Symposium Digest, 2004 IEEE MTT-S International 3, 1579–1581 (2004).
  5. A. J. Fitzgerald, B. E. Cole, and P. F. Taday, “Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging,” J. Pharm. Sci. 94(1), 177–183 (2005).
    [CrossRef] [PubMed]
  6. K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
    [CrossRef]
  7. G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
    [CrossRef] [PubMed]
  8. T. Yasui, E. Saneyoshi, and T. Araki, “Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition,” Appl. Phys. Lett. 87(6), 061101 (2005).
    [CrossRef]
  9. Q. Wu, T. D. Hewitt, and X. C. Zhang, “Two-dimensional electro-optic imaging of THz beams,” Appl. Phys. Lett. 69(8), 1026–1028 (1996).
    [CrossRef]
  10. M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
    [CrossRef] [PubMed]
  11. J. Shan, A. S. Weling, E. Knoesel, L. Bartels, M. Bonn, A. Nahata, G. A. Reider, and T. F. Heinz, “Single-shot measurement of terahertz electromagnetic pulses by use of electro-optic sampling,” Opt. Lett. 25(6), 426–428 (2000).
    [CrossRef] [PubMed]
  12. T. Yasui, K. Sawanaka, A. Ihara, E. Abraham, M. Hashimoto, and T. Araki, “Real-time terahertz color scanner for moving objects,” Opt. Express 16(2), 1208–1221 (2008).
    [CrossRef] [PubMed]
  13. M. Born and E. Wolf, Principles of Optics (Cambridge University Press, 1959), Chap. VII.
  14. Z. Jiang, X. G. Xu, and X. C. Zhang, “Improvement of terahertz imaging with a dynamic subtraction technique,” Appl. Opt. 39(17), 2982–2987 (2000).
    [CrossRef] [PubMed]
  15. H. Kubota and S. Inoue, “Diffraction images in the polarizing microscope,” J. Opt. Soc. Am. 49(2), 191–198 (1959).
    [CrossRef] [PubMed]
  16. T. Hattori and M. Sakamoto, “Deformation corrected real-time terahertz imaging,” Appl. Phys. Lett. 90(26), 261106 (2007).
    [CrossRef]
  17. M. Exter, Ch. Fattinger, and D. Grischkowsky, “Terahertz time-domain spectroscopy of water vapor,” Opt. Lett. 14(20), 1128–1130 (1989).
    [CrossRef] [PubMed]
  18. W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
    [CrossRef]
  19. G. D. Boreman, A. Dogariu, C. Christodoulou, and D. Kotter, “Dipole-on-dielectric model for infrared lithographic spiral antennas,” Opt. Lett. 21(5), 309–311 (1996).
    [CrossRef] [PubMed]

2010 (1)

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

2008 (3)

G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
[CrossRef] [PubMed]

W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
[CrossRef]

T. Yasui, K. Sawanaka, A. Ihara, E. Abraham, M. Hashimoto, and T. Araki, “Real-time terahertz color scanner for moving objects,” Opt. Express 16(2), 1208–1221 (2008).
[CrossRef] [PubMed]

2007 (1)

T. Hattori and M. Sakamoto, “Deformation corrected real-time terahertz imaging,” Appl. Phys. Lett. 90(26), 261106 (2007).
[CrossRef]

2005 (2)

T. Yasui, E. Saneyoshi, and T. Araki, “Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition,” Appl. Phys. Lett. 87(6), 061101 (2005).
[CrossRef]

A. J. Fitzgerald, B. E. Cole, and P. F. Taday, “Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging,” J. Pharm. Sci. 94(1), 177–183 (2005).
[CrossRef] [PubMed]

2003 (1)

D. A. Zimdars, “Fiber-pigtailed terahertz time domain spectroscopy instrumentation for package inspection and security imaging,” Proc. SPIE 5070, 108–116 (2003).
[CrossRef]

2002 (1)

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

2000 (2)

1999 (1)

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

1996 (2)

Q. Wu, T. D. Hewitt, and X. C. Zhang, “Two-dimensional electro-optic imaging of THz beams,” Appl. Phys. Lett. 69(8), 1026–1028 (1996).
[CrossRef]

G. D. Boreman, A. Dogariu, C. Christodoulou, and D. Kotter, “Dipole-on-dielectric model for infrared lithographic spiral antennas,” Opt. Lett. 21(5), 309–311 (1996).
[CrossRef] [PubMed]

1995 (1)

1989 (1)

1959 (1)

Abbott, D.

W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
[CrossRef]

Abraham, E.

Araki, T.

T. Yasui, K. Sawanaka, A. Ihara, E. Abraham, M. Hashimoto, and T. Araki, “Real-time terahertz color scanner for moving objects,” Opt. Express 16(2), 1208–1221 (2008).
[CrossRef] [PubMed]

T. Yasui, E. Saneyoshi, and T. Araki, “Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition,” Appl. Phys. Lett. 87(6), 061101 (2005).
[CrossRef]

Baraniuk, R. G.

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Bartels, L.

Bonn, M.

Boreman, G. D.

Christodoulou, C.

Cole, B. E.

A. J. Fitzgerald, B. E. Cole, and P. F. Taday, “Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging,” J. Pharm. Sci. 94(1), 177–183 (2005).
[CrossRef] [PubMed]

Dogariu, A.

Du, X.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Exter, M.

Fattinger, Ch.

Fischer, B. M.

W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
[CrossRef]

Fitzgerald, A. J.

A. J. Fitzgerald, B. E. Cole, and P. F. Taday, “Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging,” J. Pharm. Sci. 94(1), 177–183 (2005).
[CrossRef] [PubMed]

Fukasawa, R.

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Fukunaga, K.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Grischkowsky, D.

Gupta, M.

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Hashimoto, M.

Hattori, T.

T. Hattori and M. Sakamoto, “Deformation corrected real-time terahertz imaging,” Appl. Phys. Lett. 90(26), 261106 (2007).
[CrossRef]

Heinz, T. F.

Hewitt, T. D.

Q. Wu, T. D. Hewitt, and X. C. Zhang, “Two-dimensional electro-optic imaging of THz beams,” Appl. Phys. Lett. 69(8), 1026–1028 (1996).
[CrossRef]

Hosako, I.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Hu, B. B.

Ihara, A.

Ikari, T.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Inoue, S.

Iwamoto, T.

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Jeon, S. G.

G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
[CrossRef] [PubMed]

Jiang, Z.

Jin, Y. S.

G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
[CrossRef] [PubMed]

Kim, G. J.

G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
[CrossRef] [PubMed]

Kim, J. I.

G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
[CrossRef] [PubMed]

Kim, M.-J.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Knoesel, E.

Koch, M.

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Koezuka, T.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Kohdzuma, Y.

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

Kotter, D.

Kubota, H.

Mickan, S. P.

W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
[CrossRef]

Mittleman, D. M.

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Nahata, A.

Neelamani, R.

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Nuss, M. C.

Reider, G. A.

Rudd, J. V.

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Sakai, K.

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Sakamoto, M.

T. Hattori and M. Sakamoto, “Deformation corrected real-time terahertz imaging,” Appl. Phys. Lett. 90(26), 261106 (2007).
[CrossRef]

Saneyoshi, E.

T. Yasui, E. Saneyoshi, and T. Araki, “Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition,” Appl. Phys. Lett. 87(6), 061101 (2005).
[CrossRef]

Sawanaka, K.

Shan, J.

Taday, P. F.

A. J. Fitzgerald, B. E. Cole, and P. F. Taday, “Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging,” J. Pharm. Sci. 94(1), 177–183 (2005).
[CrossRef] [PubMed]

Tani, M.

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Usami, M.

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Watanabe, M.

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Weling, A. S.

Withayachumnankul, W.

W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
[CrossRef]

Wu, Q.

Q. Wu, T. D. Hewitt, and X. C. Zhang, “Two-dimensional electro-optic imaging of THz beams,” Appl. Phys. Lett. 69(8), 1026–1028 (1996).
[CrossRef]

Xu, X. G.

Yasui, T.

T. Yasui, K. Sawanaka, A. Ihara, E. Abraham, M. Hashimoto, and T. Araki, “Real-time terahertz color scanner for moving objects,” Opt. Express 16(2), 1208–1221 (2008).
[CrossRef] [PubMed]

T. Yasui, E. Saneyoshi, and T. Araki, “Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition,” Appl. Phys. Lett. 87(6), 061101 (2005).
[CrossRef]

Zhang, X. C.

Z. Jiang, X. G. Xu, and X. C. Zhang, “Improvement of terahertz imaging with a dynamic subtraction technique,” Appl. Opt. 39(17), 2982–2987 (2000).
[CrossRef] [PubMed]

Q. Wu, T. D. Hewitt, and X. C. Zhang, “Two-dimensional electro-optic imaging of THz beams,” Appl. Phys. Lett. 69(8), 1026–1028 (1996).
[CrossRef]

Zimdars, D. A.

D. A. Zimdars, “Fiber-pigtailed terahertz time domain spectroscopy instrumentation for package inspection and security imaging,” Proc. SPIE 5070, 108–116 (2003).
[CrossRef]

Appl. Opt. (1)

Appl. Phys. B (1)

D. M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Appl. Phys. B 68(6), 1085–1094 (1999).
[CrossRef]

Appl. Phys. Lett. (3)

T. Yasui, E. Saneyoshi, and T. Araki, “Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition,” Appl. Phys. Lett. 87(6), 061101 (2005).
[CrossRef]

Q. Wu, T. D. Hewitt, and X. C. Zhang, “Two-dimensional electro-optic imaging of THz beams,” Appl. Phys. Lett. 69(8), 1026–1028 (1996).
[CrossRef]

T. Hattori and M. Sakamoto, “Deformation corrected real-time terahertz imaging,” Appl. Phys. Lett. 90(26), 261106 (2007).
[CrossRef]

J. Europ. Opt. Soc. Rap. Public. (1)

K. Fukunaga, I. Hosako, Y. Kohdzuma, T. Koezuka, M.-J. Kim, T. Ikari, and X. Du, “Terahertz analysis of an East Asian historical mural painting,” J. Europ. Opt. Soc. Rap. Public. 5, 10024 (2010).
[CrossRef]

J. Opt. Soc. Am. (1)

J. Pharm. Sci. (1)

A. J. Fitzgerald, B. E. Cole, and P. F. Taday, “Nondestructive analysis of tablet coating thicknesses using terahertz pulsed imaging,” J. Pharm. Sci. 94(1), 177–183 (2005).
[CrossRef] [PubMed]

Opt. Express (1)

Opt. Lett. (4)

Phys. Med. Biol. (1)

M. Usami, T. Iwamoto, R. Fukasawa, M. Tani, M. Watanabe, and K. Sakai, “Development of a THz spectroscopic imaging system,” Phys. Med. Biol. 47(21), 3749–3753 (2002).
[CrossRef] [PubMed]

Proc. R. Soc. A (1)

W. Withayachumnankul, B. M. Fischer, S. P. Mickan, and D. Abbott, “Numerical removal of water-vapor effects from THz-TDS measurements,” Proc. R. Soc. A 464, 2435–2456 (2008).
[CrossRef]

Proc. SPIE (1)

D. A. Zimdars, “Fiber-pigtailed terahertz time domain spectroscopy instrumentation for package inspection and security imaging,” Proc. SPIE 5070, 108–116 (2003).
[CrossRef]

Rev. Sci. Instrum. (1)

G. J. Kim, S. G. Jeon, J. I. Kim, and Y. S. Jin, “High speed scanning of terahertz pulse by a rotary optical delay line,” Rev. Sci. Instrum. 79(10), 106102 (2008).
[CrossRef] [PubMed]

Other (2)

V. P. Wallace, A. J. Fitzgerald, B. C. Cole, R. J. Pye, and D. D. Arnone, “Biomedical applications of THz imaging,” Microwave Symposium Digest, 2004 IEEE MTT-S International 3, 1579–1581 (2004).

M. Born and E. Wolf, Principles of Optics (Cambridge University Press, 1959), Chap. VII.

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Figures (14)

Fig. 1
Fig. 1

Conceptual diagram of temporal waveform measurement by noncollinear EO sampling (CL: cylindrical lens, P: polarizer, A: analyzer).

Fig. 2
Fig. 2

Parallel temporal waveform measurement using an MSM.

Fig. 3
Fig. 3

Conceptual diagrams of three methods of expanding the time windows of temporal waveforms: (a) using an optical delay line, (b) using a rotary plate with glass plates of various thicknesses, (c) using MSMs arrayed in the y' direction.

Fig. 4
Fig. 4

Relationships between THz beam, probe laser, EO crystal, and CMOS camera.

Fig. 5
Fig. 5

Reflection of probe laser beam by an MSM inclined at 45 degrees.

Fig. 6
Fig. 6

Distributions of diffracted beam intensity obtained (a) without and (b) with correction lenses.

Fig. 7
Fig. 7

Conceptual diagram of experimental system (PCA: photoconductive antenna, TL: THz lens, BS: beam splitter, P: polarizer, A: analyzer, FG: function generator).

Fig. 8
Fig. 8

Photograph of MSM.

Fig. 9
Fig. 9

Electrical field image acquired by dynamic subtraction method. 500 frames were integrated.

Fig. 10
Fig. 10

Sampling sensitivity distribution within cell.

Fig. 11
Fig. 11

(a) Temporal waveforms and (b) THz Spectrum at the center cell in absence of the object (fast Fourier transform with zero-filling up to 1024 data points).

Fig. 12
Fig. 12

(a) Test sample used for THz imaging, (b) Amplitude image of temporal waveforms measured by this method, (c) Temporal waveforms at A and B in Fig. 12(b), (d) Spectrum at A in Fig. 12(b).

Fig. 13
Fig. 13

(a) a photograph of metal hole arrays, (b) spectroscopic images at 0.40 THz (left) and 1.00 THz (right), (c) spectra at A and B in Fig. 13(b).

Fig. 14
Fig. 14

Results obtained integrating various numbers of frames in the spectroscopic imaging of 0.4-THz and 1.0-THz MHAs. Contrast ratio is calculated from contrast values in the MHA area (solid line) and aluminum-plate area (dashed line).

Equations (7)

Equations on this page are rendered with MathJax. Learn more.

D cos θ N = p M ,
D sin θ N = c Δ t ,
d ' = N c Δ t k .
w ' + d ' = D cos θ k .
T = w ' w ' + d ' N Δ t k = { 1 N c Δ t D 2 ( N c Δ t ) 2 } N Δ t k .
u p ( x 0 ) = A i λ R exp ( i κ R ) W / 2 W / 2 exp ( i κ ( x x 0 ) 2 2 R ) d x ,
σ Q E = ( ε ε ¯ ) p ( ε ) d ε = q / 2 q / 2 ε 2 1 q d ε = q / 12 ,

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