Abstract

The application of terahertz time-domain spectroscopy (THz-TDS) and imaging to differentiate flat and curved surfaces in reflection via the THz Gouy phase shift is demonstrated. For a THz-TDS system that is aligned for reflection from a flat surface, the presence of a curved surface displaces the image focal plane from the detector plane, resulting in a Gouy phase shift. The potential of utilizing this configuration for estimating the number and size of curved objects is discussed with particular emphasis on agriculture crop yield estimates.

© 2009 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. D. Mittleman, “Terahertz imaging,” in Sensing with Terahertz Radiation, D. Mittleman, ed. (Springer, 2003), pp. 117-149.
  2. Terahertz Sensing Technology Volume 2: Emerging Scientific Applications & Novel Device Concepts, D. L. Woolard, W. R. Loerop, and M. S. Shur, eds. (World Scientific, 2003).
  3. C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
    [CrossRef]
  4. J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
    [CrossRef]
  5. J. F. Federici, D. Gary, R. Barat, and Z.-H. Michalopoulou, “Detection of explosives by terahertz imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 323.
    [CrossRef]
  6. Z.-K. Yan, H.-J Zhang, and Y.-B. Ying, “Research progress of terahertz wave technology in quality measurement of food and agricultural products,” Spectrosc. Spectral Anal. (Beijing) 27, 2228-2234 (2007).
  7. S. Hadjiloucas, L. S. Karatzas, and J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans. Microwave Theory Tech. 47, 142-149(1999)
    [CrossRef]
  8. S. Hadjiloucas, R. K. H. Galvao, and J. W. J. Bowen, “Analysis of spectroscopic measurements of leaf water content at terahertz frequencies using linear transforms,” J. Opt. Soc. Am. A 19, 2495-2509 (2002).
    [CrossRef]
  9. M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).
  10. M. Reid and R. Fedosejevs, “Terahertz birefringence and attenuation properties of wood and paper,” Appl. Opt. 45, 2766-2772 (2006).
    [CrossRef] [PubMed]
  11. H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
    [CrossRef]
  12. H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.
  13. Y. L. Hor, J. F. Federici, and R. L. Wample, “Nondestructive evaluation of cork enclosures using terahertz/millimeter wave spectroscopy and imaging,” Appl. Opt. 47, 72-78(2008).
    [CrossRef]
  14. S. E. Siegman, Lasers (University Science Books, 1986).
  15. A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
    [CrossRef]
  16. G. S. Howell, C. Schutte, and J. Treloar, “Crop estimation and sampling to achieve optimal fruit maturity and quality under michigan condition,” Final Report to the Michigan Grape and Wine Industry Council, Research and Education Advisory Committee, 2006.
  17. See, for example, D. M. Sheen, D. L. McMakin, and T. E. Hall, “Detection of explosives by millimeter-wave imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 237.
  18. R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
    [CrossRef]

2008 (1)

2007 (1)

Z.-K. Yan, H.-J Zhang, and Y.-B. Ying, “Research progress of terahertz wave technology in quality measurement of food and agricultural products,” Spectrosc. Spectral Anal. (Beijing) 27, 2228-2234 (2007).

2006 (1)

2005 (1)

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

2004 (2)

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

2002 (1)

1999 (2)

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

S. Hadjiloucas, L. S. Karatzas, and J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans. Microwave Theory Tech. 47, 142-149(1999)
[CrossRef]

1998 (1)

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Barat, R.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

J. F. Federici, D. Gary, R. Barat, and Z.-H. Michalopoulou, “Detection of explosives by terahertz imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 323.
[CrossRef]

Bleszynski, S.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Bowen, J. W.

S. Hadjiloucas, L. S. Karatzas, and J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans. Microwave Theory Tech. 47, 142-149(1999)
[CrossRef]

Bowen, J. W. J.

Chua, H. S.

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

Crawley, D.

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

Curtin, P.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Doyle, R.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Federici, J. F.

Y. L. Hor, J. F. Federici, and R. L. Wample, “Nondestructive evaluation of cork enclosures using terahertz/millimeter wave spectroscopy and imaging,” Appl. Opt. 47, 72-78(2008).
[CrossRef]

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

J. F. Federici, D. Gary, R. Barat, and Z.-H. Michalopoulou, “Detection of explosives by terahertz imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 323.
[CrossRef]

Fedosejevs, R.

Feldmann, J.

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Feng, S.

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

Fromm, J.

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Galvao, R. K. H.

Gary, D.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

J. F. Federici, D. Gary, R. Barat, and Z.-H. Michalopoulou, “Detection of explosives by terahertz imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 323.
[CrossRef]

Gibson, A. A. P.

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

Gordon, K. C.

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

Hadjiloucas, S.

S. Hadjiloucas, R. K. H. Galvao, and J. W. J. Bowen, “Analysis of spectroscopic measurements of leaf water content at terahertz frequencies using linear transforms,” J. Opt. Soc. Am. A 19, 2495-2509 (2002).
[CrossRef]

S. Hadjiloucas, L. S. Karatzas, and J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans. Microwave Theory Tech. 47, 142-149(1999)
[CrossRef]

Haigh, A. D.

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

Hall, T. E.

See, for example, D. M. Sheen, D. L. McMakin, and T. E. Hall, “Detection of explosives by millimeter-wave imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 237.

Hirsch, O.

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

Hor, Y. L.

Howell, G. S.

G. S. Howell, C. Schutte, and J. Treloar, “Crop estimation and sampling to achieve optimal fruit maturity and quality under michigan condition,” Final Report to the Michigan Grape and Wine Industry Council, Research and Education Advisory Committee, 2006.

Huang, F.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

Hunsche, S.

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Karatzas, L. S.

S. Hadjiloucas, L. S. Karatzas, and J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans. Microwave Theory Tech. 47, 142-149(1999)
[CrossRef]

Koch, M.

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Lettington, A.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Linfield, E. H.

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

Lyons, B.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

McEnroe, T.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

McMakin, D. L.

See, for example, D. M. Sheen, D. L. McMakin, and T. E. Hall, “Detection of explosives by millimeter-wave imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 237.

McNaboe, J.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Michalopoulou, Z.-H.

J. F. Federici, D. Gary, R. Barat, and Z.-H. Michalopoulou, “Detection of explosives by terahertz imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 323.
[CrossRef]

Mittleman, D.

D. Mittleman, “Terahertz imaging,” in Sensing with Terahertz Radiation, D. Mittleman, ed. (Springer, 2003), pp. 117-149.

Newnham, D. A.

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

Nuss, M. C.

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Obradovic, J.

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

Oliveira, F.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

Pepper, M.

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

Rades, T.

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

Reid, M.

Rudd, J. V.

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

Ruffin, A. B.

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

Schuacher, P.

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Schulkin, B.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

Schutte, C.

G. S. Howell, C. Schutte, and J. Treloar, “Crop estimation and sampling to achieve optimal fruit maturity and quality under michigan condition,” Final Report to the Michigan Grape and Wine Industry Council, Research and Education Advisory Committee, 2006.

Sheen, D. M.

See, for example, D. M. Sheen, D. L. McMakin, and T. E. Hall, “Detection of explosives by millimeter-wave imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 237.

Siegman, S. E.

S. E. Siegman, Lasers (University Science Books, 1986).

Strachan, C. J.

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

Taday, P. F.

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

Treloar, J.

G. S. Howell, C. Schutte, and J. Treloar, “Crop estimation and sampling to achieve optimal fruit maturity and quality under michigan condition,” Final Report to the Michigan Grape and Wine Industry Council, Research and Education Advisory Committee, 2006.

Upadhya, P. C.

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

Walsh, J.

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Wample, R. L.

Whitaker, J. F.

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

Winful, H. G.

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

Yan, Z.-K.

Z.-K. Yan, H.-J Zhang, and Y.-B. Ying, “Research progress of terahertz wave technology in quality measurement of food and agricultural products,” Spectrosc. Spectral Anal. (Beijing) 27, 2228-2234 (2007).

Ying, Y.-B.

Z.-K. Yan, H.-J Zhang, and Y.-B. Ying, “Research progress of terahertz wave technology in quality measurement of food and agricultural products,” Spectrosc. Spectral Anal. (Beijing) 27, 2228-2234 (2007).

Zhang, H.-J

Z.-K. Yan, H.-J Zhang, and Y.-B. Ying, “Research progress of terahertz wave technology in quality measurement of food and agricultural products,” Spectrosc. Spectral Anal. (Beijing) 27, 2228-2234 (2007).

Zimdars, D.

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

Appl. Opt. (2)

Chem. Phys. Lett. (1)

C. J. Strachan, T. Rades, D. A. Newnham, K. C. Gordon, M. Pepper, and P. F. Taday, “Using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials,” Chem. Phys. Lett. 390, 20-24 (2004).
[CrossRef]

IEEE Trans. Microwave Theory Tech. (1)

S. Hadjiloucas, L. S. Karatzas, and J. W. Bowen, “Measurements of leaf water content using terahertz radiation,” IEEE Trans. Microwave Theory Tech. 47, 142-149(1999)
[CrossRef]

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

Phys. Rev. Lett. (1)

A. B. Ruffin, J. V. Rudd, J. F. Whitaker, S. Feng, and H. G. Winful, “Direct observation of the Gouy phase shift with single-cycle terahertz pulses,” Phys. Rev. Lett. 83, 3410-3413 (1999).
[CrossRef]

Proc. SPIE (1)

R. Doyle, B. Lyons, A. Lettington, T. McEnroe, J. Walsh, J. McNaboe, P. Curtin, and S. Bleszynski, “Stand-off detection of hidden threat objects on personnel at checkpoints and in public areas using active millimetre-wave imaging,” Proc. SPIE 5619, 90-97 (2004).
[CrossRef]

Semicond. Sci. Technol. (1)

J. F. Federici, B. Schulkin, F. Huang, D. Gary, R. Barat, F. Oliveira, and D. Zimdars, “THz imaging and sensing for security applications--explosives, weapons, and drugs,” Semicond. Sci. Technol. 20, S266-S280 (2005).
[CrossRef]

Spectrosc. Spectral Anal. (Beijing) (1)

Z.-K. Yan, H.-J Zhang, and Y.-B. Ying, “Research progress of terahertz wave technology in quality measurement of food and agricultural products,” Spectrosc. Spectral Anal. (Beijing) 27, 2228-2234 (2007).

Wood Sci. Technol. (1)

M. Koch, S. Hunsche, P. Schuacher, M. C. Nuss, J. Feldmann, and J. Fromm, “THz-imaging: A new method for density mapping of wood,” Wood Sci. Technol. 32, 421-427(1998).

Other (8)

H. S. Chua, P. C. Upadhya, A. D. Haigh, J. Obradovic, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of wheat grain,” in Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics (IEEE, 2004), pp 399-400.
[CrossRef]

H. S. Chua, J. Obradovic, A. D. Haigh, P. C. Upadhya, O. Hirsch, D. Crawley, A. A. P. Gibson, and E. H. Linfield, “Terahertz time-domain spectroscopy of crushed wheat grain,” in 2005 IEEE MTT-S International Microwave Symposium (IEEE, 2005), p 4.

S. E. Siegman, Lasers (University Science Books, 1986).

J. F. Federici, D. Gary, R. Barat, and Z.-H. Michalopoulou, “Detection of explosives by terahertz imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 323.
[CrossRef]

D. Mittleman, “Terahertz imaging,” in Sensing with Terahertz Radiation, D. Mittleman, ed. (Springer, 2003), pp. 117-149.

Terahertz Sensing Technology Volume 2: Emerging Scientific Applications & Novel Device Concepts, D. L. Woolard, W. R. Loerop, and M. S. Shur, eds. (World Scientific, 2003).

G. S. Howell, C. Schutte, and J. Treloar, “Crop estimation and sampling to achieve optimal fruit maturity and quality under michigan condition,” Final Report to the Michigan Grape and Wine Industry Council, Research and Education Advisory Committee, 2006.

See, for example, D. M. Sheen, D. L. McMakin, and T. E. Hall, “Detection of explosives by millimeter-wave imaging,” in Counter-Terrorism Detection Techniques of Explosives, J. Yinon, ed. (Elsevier, 2007), p. 237.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (6)

Fig. 1
Fig. 1

(A) Visible image of three grapes from 18 June. The toothpick in the picture is used to hold the sample fixed during the image acquisition. (B) Corresponding THz image. The image is 137 by 83 pixels. Each pixel is 0.3 mm square. THz images are based on average transmission between 0.15 0.2 THz of a grape (C) and a grape hidden behind a grape leaf (D).

Fig. 2
Fig. 2

(A) Comparison of the reflectance spectra (bottom three curves) of a berry (black), leaf (dark gray), and stem (light gray). The sharp peak near 0.557 THz is an artifact of absorption by ambient water vapor in the air. The spectra of the reference are shown in the dashed top curve. (B) Reflectance spectra of the three grapes (18 June) of Fig. 1. The interference fringes from multiple reflections in the silicon lenses have been removed. The signal THz signal from the berry is about 2 orders of magnitude above the noise floor of the THz system at 0.5 THz .

Fig. 3
Fig. 3

(A) Comparison of THz time-domain waveforms (18 June) of the reference (middle trace), stem (upper), and leaf (lower) (B) reference (lower trace) and grape (upper trace). The time axes and amplitudes have been normalized for comparison of the pulse shapes. The traces are offset in the vertical direction for clarity. The reflection spectra of Fig. 2 are calculated from the magnitude of the Fourier transforms of the time-domain data. The small peaks in the data near 62 ps are from multiple reflections within the silicon lenses.

Fig. 4
Fig. 4

(A) For simplicity, the experimental reflective geometry is analyzed as a transmission system. The diverging lens ( d 1 ) with focal length f g in the figure represents the grape. THz radiation is emitted from the THz transmitter (TX) and collimated by lens L1 to a beam diameter of ω 0 . Lens L2 (focal length f) focuses the THz radiation, while lens L3 (focal length f) collects the THz beam after focusing. In the absence of the diverging lens, lens L4 focuses the THz radiation on the THz receiver RX. When the diverging lens is present (dashed line), the THz radiation focuses at a point Z beyond the THz receiver. (B) Plot of Gouy phase shift as a function of distance Z. The optical configuration including the berry corresponds to a negative distance Z. (C) Measured reflected THz waveform from a typical grape (solid black curve). The dashed black curve corresponds to an added correction for the frequency dependent reflectivity of the berry but no correction to the phase shift. The addition of a π / 2 phase shift (gray curve) accurately reproduces the measured waveform.

Fig. 5
Fig. 5

(A) Typical THz time-domain waveforms from bright reflection pixels of the leaf, flower, reference, and stem (from top curve to bottom). Inset: visible image of a flower cluster on 14 May prior to bloom. (B) Comparison among the reference waveform (bottom trace), the reflected THz waveform from a berry (1 June) in the inset (middle), and the predicted THz reflection (top) from the berry.

Fig. 6
Fig. 6

Change of THz pulse shape with the local curvature of the grape’s surface. The bottom plot shows the reflected THz pulse from the specular reflection from brightest part of the THz image (bottom inset). The top curves show the reflected THz pulses from positions A, B, C, and D, which are all 2 mm from the position of the brightest specular reflection. Note that the shapes of pulses A, B, C, and D are similar to each other but different from the specularly reflected pulse.

Equations (6)

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

ψ ( z ) = tan 1 ( z Z R ) ,
[ A B C D ] = [ 1 0 1 / f 1 ] [ 1 f + d 1 0 1 ] [ 1 0 1 / f g 1 ] [ 1 f d 1 0 1 ] [ 1 0 1 / f 1 ] [ 1 d 2 0 1 ] [ 1 0 1 / f o 1 ] [ 1 f o 0 1 ] .
q ^ RX = A q ^ 0 + B C q ^ 0 + D ,
q ^ 0 = i π ω o 2 λ 0 ;
exp ( i ψ ) = A + B / q ^ 0 | A + B / q ^ 0 | .
sin ( ψ g ψ 0 ) = f 2 / f o f g [ ( f 2 / f o f g ) 2 + ( λ o f o / π ω 0 2 ) 2 ] 1 / 2 .

Metrics