Abstract

Through theoretical modeling, we find that the dynamics of photogenerated carriers play a very important role in shaping the temporal waveform of terahertz (THz) radiation pulses emitted from biased low-temperature (LT)-grown GaAs antenna. Our modeling gives successful analyses for the sharp and short, slow and long negative parts of temporal THz waveforms. By including intraband, carrier relaxation effects in the modeled mobility, we find an obvious dependence of the THz conversion efficiency on the material of THz emitter and experimental parameters such as the optical duration, the center wavelength, and the fluence of the laser pulses. Our research also shows that electron-hole and electron-electron collisions in LT-GaAs contribute to the saturation phenomenon with an increase of laser fluence.

© 2003 Optical Society of America

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References

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  1. D. Grischkowsky, S. Keiding, M. van Exter, Ch. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. B 7, 2006–2015 (1990).
    [CrossRef]
  2. M. Schall, P. U. Jepsen, “Photoexcited GaAs surfaces studied by transient terahertz time-domain spectroscopy,” Opt. Lett. 25, 13–15 (2000).
    [CrossRef]
  3. H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
    [CrossRef]
  4. T.-I. Jeon, D. R. Grischkowsky, “Observation of a Cole-Davidson type complex conductivity in the limit of very low carrier densities in doped silicon,” Applied. Phys. Lett. 72, 2259–2261 (1998).
    [CrossRef]
  5. M. van Exter, D. R. Grischkowsky, “Characterization of an optoelectronic terahertz beam system,” IEEE Trans. Microwave Theory Tech. 38, 1684–1691 (1990).
    [CrossRef]
  6. D.-M. Mittleman, R. H. Jacobsen, M. C. Nuss, “T-ray imaging,” IEEE J. Sel. Top. Quantum Electron. 2, 679–692 (1996).
    [CrossRef]
  7. S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
    [CrossRef]
  8. M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
    [CrossRef]
  9. A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
    [CrossRef]
  10. A. Gurtler, C. Winnewisser, H. Helm, P. U. Jepsen, “Terahertz pulse propagation in the near field and the far field,” J. Opt. Soc. Am. A 17, 74–83 (2000).
    [CrossRef]
  11. E. Budiarto, N.-W. Pu, S. Jeong, J. Bokor, “Near-field propagation of terahertz pulses from a large-aperture antenna,” Opt. Lett. 23, 213–215 (1998).
    [CrossRef]
  12. P. U. Jepsen, R. H. Jacobsen, S. R. Keiding, “Generation and detection of terahertz pulse from biased semiconductor antennas,” J. Opt. Soc. Am. B 13, 2424–2436 (1996).
    [CrossRef]
  13. P. K. Benicewicz, J. P. Roberts, A. J. Taylor, “Scaling of terahertz radiation from large-aperture biased photoconductors,” J. Opt. Soc. Am. B 11, 2533–2546 (1994).
    [CrossRef]
  14. A. J. Taylor, P. K. Benicewicz, S. M. Young, “Modeling of femtosecond electromagnetic pulses from large-aperture photoconductors,” Opt. Lett. 18, 1340–1342 (1993).
    [CrossRef] [PubMed]
  15. D. You, R. R. Jones, P. H. Bucksbaum, D. R. Dykaar, “Generation of high-power sub-single-cycle 500-fs electromagnetic pulses,” Opt. Lett. 18, 290–292 (1993).
    [CrossRef] [PubMed]
  16. J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
    [CrossRef]
  17. K.-H. Hellwege, O. Madelung, eds., Landolt-Bornstein, Vol. 17a of Semiconductors, Physics of Group IV elements and III-V Compounds (Springer-Verlag, New York, 1982).
  18. B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
    [CrossRef]
  19. P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
    [CrossRef]
  20. S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
    [CrossRef]
  21. S.-G. Park, M. R. Melloch, A. M. Weiner, “Analysis of terahertz waveforms measured by photoconductive and electrooptic sampling,” IEEE J. Quantum Electron. 35, 810–819 (1999).
    [CrossRef]
  22. X.-C. Zhang, D. H. Austonm, “Optoelectronic measurement of semiconductor surfaces and interface with femtosecond optics,” J. Appl. Phys. 71, 326–338 (1991).
    [CrossRef]

2001

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

2000

1999

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

S.-G. Park, M. R. Melloch, A. M. Weiner, “Analysis of terahertz waveforms measured by photoconductive and electrooptic sampling,” IEEE J. Quantum Electron. 35, 810–819 (1999).
[CrossRef]

M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
[CrossRef]

A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
[CrossRef]

1998

T.-I. Jeon, D. R. Grischkowsky, “Observation of a Cole-Davidson type complex conductivity in the limit of very low carrier densities in doped silicon,” Applied. Phys. Lett. 72, 2259–2261 (1998).
[CrossRef]

S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
[CrossRef]

E. Budiarto, N.-W. Pu, S. Jeong, J. Bokor, “Near-field propagation of terahertz pulses from a large-aperture antenna,” Opt. Lett. 23, 213–215 (1998).
[CrossRef]

1996

1994

1993

1992

J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
[CrossRef]

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
[CrossRef]

1991

X.-C. Zhang, D. H. Austonm, “Optoelectronic measurement of semiconductor surfaces and interface with femtosecond optics,” J. Appl. Phys. 71, 326–338 (1991).
[CrossRef]

1990

D. Grischkowsky, S. Keiding, M. van Exter, Ch. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. B 7, 2006–2015 (1990).
[CrossRef]

M. van Exter, D. R. Grischkowsky, “Characterization of an optoelectronic terahertz beam system,” IEEE Trans. Microwave Theory Tech. 38, 1684–1691 (1990).
[CrossRef]

Adam, D.

M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
[CrossRef]

Auston, D. H.

J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
[CrossRef]

Austonm, D. H.

X.-C. Zhang, D. H. Austonm, “Optoelectronic measurement of semiconductor surfaces and interface with femtosecond optics,” J. Appl. Phys. 71, 326–338 (1991).
[CrossRef]

Benicewicz, P. K.

Bokor, J.

Brener, I.

S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
[CrossRef]

Bucksbaum, P. H.

Budiarto, E.

Chung, S. L.

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

Dapkus, L.

A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
[CrossRef]

Darrow, J. T.

J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
[CrossRef]

Dykaar, D. R.

D. You, R. R. Jones, P. H. Bucksbaum, D. R. Dykaar, “Generation of high-power sub-single-cycle 500-fs electromagnetic pulses,” Opt. Lett. 18, 290–292 (1993).
[CrossRef] [PubMed]

P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
[CrossRef]

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

Fattinger, Ch.

Federici, J. F.

P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
[CrossRef]

Greene, B. I.

P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
[CrossRef]

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

Grischkowsky, D.

Grischkowsky, D. R.

T.-I. Jeon, D. R. Grischkowsky, “Observation of a Cole-Davidson type complex conductivity in the limit of very low carrier densities in doped silicon,” Applied. Phys. Lett. 72, 2259–2261 (1998).
[CrossRef]

M. van Exter, D. R. Grischkowsky, “Characterization of an optoelectronic terahertz beam system,” IEEE Trans. Microwave Theory Tech. 38, 1684–1691 (1990).
[CrossRef]

Gurtler, A.

Helm, H.

Hunsche, S.

S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
[CrossRef]

Jacobsen, R. H.

Jeon, T.-I.

T.-I. Jeon, D. R. Grischkowsky, “Observation of a Cole-Davidson type complex conductivity in the limit of very low carrier densities in doped silicon,” Applied. Phys. Lett. 72, 2259–2261 (1998).
[CrossRef]

Jeong, S.

Jepsen, P. U.

Jones, R. R.

Keiding, S.

Keiding, S. R.

Khazan, M.

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

Koch, M.

S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
[CrossRef]

Krotkus, A.

A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
[CrossRef]

Kuzel, P.

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

Marcinkevicius, S.

A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
[CrossRef]

Melloch, M. R.

S.-G. Park, M. R. Melloch, A. M. Weiner, “Analysis of terahertz waveforms measured by photoconductive and electrooptic sampling,” IEEE J. Quantum Electron. 35, 810–819 (1999).
[CrossRef]

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

Mittleman, D.-M.

D.-M. Mittleman, R. H. Jacobsen, M. C. Nuss, “T-ray imaging,” IEEE J. Sel. Top. Quantum Electron. 2, 679–692 (1996).
[CrossRef]

Morse, J. D.

J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
[CrossRef]

Nagle, J.

M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
[CrossRef]

Nemec, H.

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

Nuss, M. C.

S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
[CrossRef]

D.-M. Mittleman, R. H. Jacobsen, M. C. Nuss, “T-ray imaging,” IEEE J. Sel. Top. Quantum Electron. 2, 679–692 (1996).
[CrossRef]

Olin, U.

A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
[CrossRef]

Park, S.-G.

S.-G. Park, M. R. Melloch, A. M. Weiner, “Analysis of terahertz waveforms measured by photoconductive and electrooptic sampling,” IEEE J. Quantum Electron. 35, 810–819 (1999).
[CrossRef]

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

Pashkin, A.

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

Pu, N.-W.

Roberts, J. P.

Saeta, P. N.

P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
[CrossRef]

Saete, P. N.

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

Schall, M.

Schmitt-Rink, S.

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

Schnell, J.-P.

M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
[CrossRef]

Schnull, S.

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

Siders, C. W.

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

Siders, J. L. W.

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

Stellmacher, M.

M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
[CrossRef]

Taylor, A. J.

van Exter, M.

D. Grischkowsky, S. Keiding, M. van Exter, Ch. Fattinger, “Far-infrared time-domain spectroscopy with terahertz beams of dielectrics and semiconductors,” J. Opt. Soc. Am. B 7, 2006–2015 (1990).
[CrossRef]

M. van Exter, D. R. Grischkowsky, “Characterization of an optoelectronic terahertz beam system,” IEEE Trans. Microwave Theory Tech. 38, 1684–1691 (1990).
[CrossRef]

Weiner, A. M.

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

S.-G. Park, M. R. Melloch, A. M. Weiner, “Analysis of terahertz waveforms measured by photoconductive and electrooptic sampling,” IEEE J. Quantum Electron. 35, 810–819 (1999).
[CrossRef]

Wilke, I.

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

Winnewisser, C.

You, D.

Young, S. M.

Zhang, X.-C.

J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
[CrossRef]

X.-C. Zhang, D. H. Austonm, “Optoelectronic measurement of semiconductor surfaces and interface with femtosecond optics,” J. Appl. Phys. 71, 326–338 (1991).
[CrossRef]

Appl. Phys. Lett.

M. Stellmacher, J.-P. Schnell, D. Adam, J. Nagle, “Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature,” Appl. Phys. Lett. 74, 1239–1241 (1999).
[CrossRef]

A. Krotkus, L. Dapkus, U. Olin, S. Marcinkevicius, “Ultrafast carrier trapping in Be-doped low-temperature-grown GaAs,” Appl. Phys. Lett. 75, 3336–3339 (1999).
[CrossRef]

P. N. Saeta, J. F. Federici, B. I. Greene, D. R. Dykaar, “Intervalley scattering in GaAs and InP probed by pulsed far-infrared transmission spectroscopy,” Appl. Phys. Lett. 60, 1477–1479 (1992).
[CrossRef]

Applied. Phys. Lett.

T.-I. Jeon, D. R. Grischkowsky, “Observation of a Cole-Davidson type complex conductivity in the limit of very low carrier densities in doped silicon,” Applied. Phys. Lett. 72, 2259–2261 (1998).
[CrossRef]

IEEE J. Quantum Electron.

J. T. Darrow, X.-C. Zhang, D. H. Auston, J. D. Morse, “Saturation properties of large-aperture photoconducting antennas,” IEEE J. Quantum Electron. 28, 1607–1616 (1992).
[CrossRef]

S.-G. Park, A. M. Weiner, M. R. Melloch, C. W. Siders, J. L. W. Siders, A. J. Taylor, “High-power narrow-band terahertz generation using large-aperture photoconductors,” IEEE J. Quantum Electron. 35, 1257–1267 (1999).
[CrossRef]

S.-G. Park, M. R. Melloch, A. M. Weiner, “Analysis of terahertz waveforms measured by photoconductive and electrooptic sampling,” IEEE J. Quantum Electron. 35, 810–819 (1999).
[CrossRef]

B. I. Greene, P. N. Saete, D. R. Dykaar, S. Schmitt-Rink, S. L. Chung, “Far-infrared light generation at semiconductor surfaces and its spectroscopic applications,” IEEE J. Quantum Electron. 28, 2302–2312 (1992).
[CrossRef]

IEEE J. Sel. Top. Quantum Electron.

D.-M. Mittleman, R. H. Jacobsen, M. C. Nuss, “T-ray imaging,” IEEE J. Sel. Top. Quantum Electron. 2, 679–692 (1996).
[CrossRef]

IEEE Trans. Microwave Theory Tech.

M. van Exter, D. R. Grischkowsky, “Characterization of an optoelectronic terahertz beam system,” IEEE Trans. Microwave Theory Tech. 38, 1684–1691 (1990).
[CrossRef]

J. Appl. Phys.

X.-C. Zhang, D. H. Austonm, “Optoelectronic measurement of semiconductor surfaces and interface with femtosecond optics,” J. Appl. Phys. 71, 326–338 (1991).
[CrossRef]

H. Nemec, A. Pashkin, P. Kuzel, M. Khazan, S. Schnull, I. Wilke, “Carrier dynamics in low-temperature grown GaAs studied by THz emission spectroscopy,” J. Appl. Phys. 90, 1303–1317 (2001).
[CrossRef]

J. Opt. Soc. Am. A

J. Opt. Soc. Am. B

Opt. Commun.

S. Hunsche, M. Koch, I. Brener, M. C. Nuss, “THz near-field imaging,” Opt. Commun. 150, 22–26 (1998).
[CrossRef]

Opt. Lett.

Other

K.-H. Hellwege, O. Madelung, eds., Landolt-Bornstein, Vol. 17a of Semiconductors, Physics of Group IV elements and III-V Compounds (Springer-Verlag, New York, 1982).

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Figures (8)

Fig. 1
Fig. 1

Band structure of LT-GaAs at 300 K is assumed in this study to be the same as that of GaAs, except that LT-GaAs contains deep traps (associated with the As clusters). Decay processes of the photoexcited carriers at 700- and 580-nm excitation wavelength are showed. The L and X valley minima are 0.3 and 0.46 eV above the Γ valley minimum, respectively. The energy gap between the top of valence band and the bottom of conduction band is 1.43 eV.

Fig. 2
Fig. 2

Theoretical waveforms of the radiated electric field E r (t) versus time from the LT-GaAs emitter. (top): LT-GaAs (T g = 280 °C, T a = 600 °C); (bottom): GaAs. (An optical pulse wavelength of 800 nm and width of 100 fs is assumed to combine with experimental parameters in Refs. 19 and 20.)

Fig. 3
Fig. 3

Theoretical waveforms of the radiated electric field E r (t) versus time from GaAs emitter. An optical pulse wavelength of 618 nm and width of 70 fs is assumed to combine with experimental parameters in Ref. 16. m i = 150 cm2/V s, m f = 1510 cm2/V s, τcar = 100 ps, τ m = 2 ps for curve 1; τ m = 200 ps for curve 2.

Fig. 4
Fig. 4

Theoretical waveforms of the radiated electric field E r (t) versus time from three different LT-GaAs emitters. For curves 1, 2, and 3, τcar = 0.28, 0.37, and 0.45 ps, respectively. An optical pulse wavelength λ o 800 nm and a width τopt 0.2 ps is assumed; m i = m f = 1510 cm2/V s and τ m = 2 ps are assumed.

Fig. 5
Fig. 5

Theoretical waveforms of terahertz pulse versus time from a LT-GaAs emitter for different optical pulse width. (τopt = 0.06, 0.1, and 0.13 ps for curves 1, 2, and 3 are assumed, respectively; the same values of m i , m f , τ m , and λ o with those of Fig. 4).

Fig. 6
Fig. 6

Theoretic waveforms of terahertz pulse versus time from a LT-GaAs emitter with different choices of optical excitation wavelength. For curves 1 and 2, λ o = 700 and 580 nm, respectively. τcar = 0.28 ps, τ o = 0.3 ps, and τ m = 1.5 ps are assumed.

Fig. 7
Fig. 7

Spectra of the waveforms in Fig. 4. Curves 1, 2, and 3 are transformed from waveforms 1, 2, and 3 from Fig. 4, respectively.

Fig. 8
Fig. 8

Power spectral density of terahertz radiation from LT-GaAs emitters at the frequency of 0.3 THz versus the fluence of optical pulse with B = 40 cm2/mJ in logarithm coordinates. λ o = 800 nm is assumed. Curves 1, 2, and 3 correspond to the emitters with carrier lifetime of 100, 0.6, and 0.3 ps.

Equations (5)

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Ert=-AEb4πz0c2dσsdt1+σsη01+n2,
σst=e1-Rω-tdtmt, t×Iopttexp-t-tτcar,
Ioptt=Io exp-t2τ02.
mt, t=mf-mf-miexp-t-t/τm1+B -t Iotexp-t-t/τcardt,
σs,max=e1-RmtrFoptω,

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