Generation of Ultra-Wideband Terahertz Pulse by Photoconductive Antenna

광전도안테나에 의한 광대역테라헤르츠파의 발생특성

  • 진윤식 (한국전기연구원 전기물리그룹) ;
  • 김근주 (한국전기연구원 전기물리그룹) ;
  • 손채화 (한국전기연구원 전기물리그룹) ;
  • 정순신 (한국전기연구원 전기물리그룹) ;
  • 김지현 (한국전기연구원 전기물리그룹) ;
  • 전석기 (한국전기연구원 전기물리그룹)
  • Published : 2005.06.01


Terahertz wave is a kind of electromagnetic radiation whose frequency lies in 0.1THz $\~$10THz range. In this paper, generation and detection characteristics of terahertz (THz) radiation by photoconductive antenna (PCA) method has been described. Using modern integrated circuit techniques, micron-sized dipole antenna has been fabricated on a low-temperature grown GaAs (LT-GaAs) wafer. A mode-locked Ti:Sapphire femtosecond laser beam is guided and focused onto photoconductive antennas (emitter and detector) to generate and measure THz pulses. Ultra-wide band THz radiation with frequencies between 0.1 THz and 3 THz was observed. Terahertz field amplitude variation with antenna bias voltage, pump laser power, pump laser wavelength and probe laser power was investigated. As a primary application example. a live clover leaf was imaged with the terahertz radiation.


Terahertz(THz) Radiation;Femtosecond Lase; Photoconductive Antenna;LT-GaAs;Ultra-Wideband Radiation;T-Ray Imaging


  1. N. Katzenenbogen and D. Grischkowsky, 'An Ultra-Wideband Optoelectronic THz beam System', Ultra-Wideband, Shrt-Pulse Electromagnetics, Ed. H. Bertoni et al., Plenum Press, pp. 7-20, 1993
  2. L. Duvillaret, F. Garet, and J. J. Coutaz : 'A Reliable Method for Extraction of Material Parameters in Terahertz Time-Domain Spectroscopy,' IEEE J. Selected Topics in Quantum Electron., 2, pp.739-746, 1996
  3. 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, pp. 1085-1094, 1999
  4. S. Gupta, M.Y. Frankel, J. A. Valdmanis, J. F. itaker, G.A.Mourou, F. W. Smith and A.R. Calawa : 'Subpicosecond carrier lifetimein GaAs grown by molecular beam epitaxy at low temperatures', Appl. Phys. Lett. 59, pp. 3276-3278, 1991
  5. D.C.Look : 'Molecular beam epitaxial GaAs grown at low temperature', Thin Solid Films 231, pp. 61-73, 1993
  6. D. Dragoman and M. Dragoman : 'Terahertz field and applications', Progress in Quantum Electronics 28, pp. 1-66, 2002
  7. J. V. Rudd and D.M.Mittleman, 'Influence of substrate-lens design in terahertz time-domain spectroscopy', J. Opt. Soc. Am. B. vol. 19 pp.319-329, 2002
  8. M.Tany, S.Matsuura, K.Sakai, and S.Nakashima : 'Emission characteristics of photoconductive antennas based on low-temperature-grown GaAs and semi-insulating GaAs', Appl. Optics 36, pp. 853-7859, 1997
  9. Stephen E. Ralph and D. Grischkowsky, 'Trap-enhanced electric fields in semi-insulators : The role of electrical and optical carrier injection', Appl. Phys. Lett. 59, pp.1972-1974,1991
  10. P. K. Benicewicz, J. P. Roberts, and A.J. Taylor : 'Scaling of terahertz radiation from large-aperture biased photoconductors', J Opt. Soc. Am., B, 11, pp. 2533- 2546, 1994
  11. M.V.Exter, C. Fattinger and D. Grischkowsky, 'Terahertz time-domain spectroscopy of water vapor', Opt. Lett. 14, pp. 1128-1130, 1989