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Cutting-edge terahertz technology


Research into terahertz technology is now receiving increasing attention around the world, and devices exploiting this waveband are set to become increasingly important in a very diverse range of applications. Here, an overview of the status of the technology, its uses and its future prospects are presented.

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Figure 1: Welcome to the terahertz region.
Figure 2: Typical design of a solid-state source of tunable THz waves based on an injection-seeded THz-wave parametric generator.
Figure 3: Semiconductor source of THz waves based on a QCL design.
Figure 4: Typical set-up for THz-TDS.
Figure 5: THz-absorption spectra of barbital.
Figure 6: MOSFET damage detection by LTEM.
Figure 7: Terahertz narcotic detection a, THz image (upper) and photograph (lower) of specimens under inspection.
Figure 8: Expected roadmap for some THz applications.


  1. 1

    Ferguson, B. & Zhang, X.-C. Materials for terahertz science and technology. Nature Mater. 1, 26–33 (2002).

    ADS  Article  Google Scholar 

  2. 2

    Siegel, P. H. Terahertz technology. IEEE Trans. Microwave Theory Tech. 50, 910–928 (2002).

    ADS  Google Scholar 

  3. 3

    Schmuttenmaer, C. A. Exploring dynamics in the far-infrared with terahertz spectroscopy. Chem. Rev. 104, 1759–1779 (2004).

    Google Scholar 

  4. 4

    Siegel, P. H. Terahertz technology in biology and medicine. IEEE Trans. Microwave Theory Tech. 52, 2438–2446 (2004).

    ADS  Google Scholar 

  5. 5

    Mittleman, D. Sensing with Terahertz Radiation (Springer, Berlin, 2003).

    Google Scholar 

  6. 6

    Sakai, K. Terahertz Optoelectronics (Springer, Berlin, 2005).

    Google Scholar 

  7. 7

    Tonouchi, M. Terahertz Technology (Ohmsha, Tokyo, 2006).

    Google Scholar 

  8. 8

    Kawase, K., Shikata, J. & Ito, I. Terahertz wave parametric source. J. Phys. D 34, R1–R14 (2001).

    ADS  Google Scholar 

  9. 9

    Cook, D. J. & Hochstrasser, R. M. Intense terahertz pulses by four-wave rectification in air. Opt. Lett. 25, 1210–1212 (2000).

    ADS  Google Scholar 

  10. 10

    Faist, J. et al. Quantum cascade laser. Science 264, 553–556 (1994).

    ADS  Google Scholar 

  11. 11

    Kohler, R. et al. Terahertz semiconductor-heterostructure laser. Nature 417, 156–159 (2002).

    ADS  Google Scholar 

  12. 12

    Vitiello, M. S. et al. Electron-lattice coupling in bound-to-continuum THz quantum-cascade lasers. Appl. Phys. Lett. 88, 241109 (2006).

    ADS  Google Scholar 

  13. 13

    Straub, A. et al. Threshold reduction in quantum cascade lasers with partially undoped, dual-wavelength interdigitated cascades. Appl. Phys. Lett. 80, 2845–2847 (2002).

    ADS  Google Scholar 

  14. 14

    Hu, Q. et al. Resonant-phonon-assisted THz quantum-cascade lasers with metal–metal waveguides. Semicond. Sci. Technol. 20, S228–S236 (2005).

    ADS  Google Scholar 

  15. 15

    Scalari, G., Walther, C., Faist, J., Beere, H. & Ritchie, D. Electrically switchable, two-color quantum cascade laser emitting at 1.39 and 2.3 THz. Appl. Phys. Lett. 88, 141102 (2006).

    ADS  Google Scholar 

  16. 16

    Ito, H., Nakajima, F., Furuta, T. & Ishibashi, T. Continuous THz-wave generation using antenna-integrated uni-travelling-carrier photodiodes. Semicond. Sci. Technol. 20, S191–S198 (2005).

    ADS  Google Scholar 

  17. 17

    Otsuji, T., Hanabe, M. & Nishimura, T. A granting-bicoupled plasma-wave photomixer with resonant-cavity enhanced structure. Opt. Express 14, 4815–4825 (2006).

    ADS  Google Scholar 

  18. 18

    Sekine, N. & Hirakawa, K. Dispersive terahertz gain of a nonclassical oscillator: Bloch oscillation in semiconductor superlattices. Phys. Rev. Lett. 94, 057408 (2005).

    ADS  Google Scholar 

  19. 19

    Orihashi, N., Suzuki, S. & Asada, M. One THz harmonic oscillation of resonant tunneling diodes. Appl. Phys. Lett. 87, 233501 (2005).

    ADS  Google Scholar 

  20. 20

    Crowe, T. W., Bishop, W. L., Perterfield, D. W., Hesler, J. L. & Weikle, R. M. Opening the terahertz window with integrated diode circuits. IEEE J. Solid-State Circuits 40, 2104–2110 (2005).

    ADS  Google Scholar 

  21. 21

    Williams, G. P. Far-IR/THz radiation from the Jefferson Laboratory, energy recovered linac, free electron laser. Rev. Sci. Instr. 73, 1461–1463 (2002).

    ADS  Google Scholar 

  22. 22

    Bergner, A. et al. New p-Ge THz laser spectrometer for the study of solutions: THz absorption spectroscopy of water. Rev. Sci. Instr. 76, 063110 (2005).

    ADS  Google Scholar 

  23. 23

    Kübler, C., Huber, R. & Leitenstorfer, A. Ultrabroadband terahertz pulses: Generation and field-resolved detection. Semicond. Sci. Technol. 20, S128–S133 (2005).

    ADS  Google Scholar 

  24. 24

    Miller, A. J., Luukanen, A. & Grossman, E. N. Micromachined antenna-coupled uncooled microbolometers for terahertz imaging arrays. Proc. SPIE 5411, 8–24 (2004).

    ADS  Google Scholar 

  25. 25

    Yasui, T., Nishimura, A., Suzuki, T., Nakayama, K. & Okajima, S. Detection system operating at up to 7 THz using quasioptics and Schottky barrier diodes. Rev. Sci. Instr. 77, 066102 (2006).

    ADS  Google Scholar 

  26. 26

    Ariyoshi, S. Terahertz imaging with a direct detector based on superconducting tunnel junctions. Appl. Phys. Lett. 88, 203503 (2006).

    ADS  Google Scholar 

  27. 27

    Komiyama, S., Astafiev, O., Antonov, V., Kutsuwa, T. & Hirai, H. A single-photon detector in the far-infrared range. Nature 403, 405–407 (2000).

    ADS  Google Scholar 

  28. 28

    Han, P. Y. & Zhang, X.-C. Free-space coherent broadband terahertz time-domain spectroscopy. Meas. Sci. Technol. 12, 1747–1756 (2001).

    ADS  Google Scholar 

  29. 29

    Liu, K., Xu, J., Yuan, T. & Zhang, X.-C. Terahertz radiation from InAs induced by carrier diffusion and drift. Phys. Rev. B 73, 155330 (2006).

    ADS  Google Scholar 

  30. 30

    Schneider, A., Stillhart, M. & Günter, P. High efficiency generation and detection of terahertz pulses using laser pulses at telecommunication wavelengths. Opt. Express 14, 5376–5384 (2006).

    ADS  Google Scholar 

  31. 31

    Ashida, M. et al. Sensitivity of photoconductive antenna for ultrabroadband terahertz radiation: Feasibility of detection over 100THz. JFH1-2, Tech. Dig. IQEC/CLEO-PR (2005).

    Google Scholar 

  32. 32

    Suto, K. & Nishizawa, J. Widely frequency-tunable terahertz wave generation and spectroscopic application. Int. J. Infrared and Millimeter Waves 26, 937–952 (2005).

    ADS  Google Scholar 

  33. 33

    Wu, Q., Hewitt, T. D. & Zhang, X.-C. Two-dimensional electrooptic imaging of THz beams. Appl. Phys. Lett. 69, 1026–1028 (1996).

    ADS  Google Scholar 

  34. 34

    Mitttleman, D. M., Jacobsen, R. H. & Nuss, M. C. T-ray imaging. IEEE J. Sel. Top. Quant. Electron. 2, 679–692 (1996).

    ADS  Google Scholar 

  35. 35

    Mitttleman, D. M., Hunsche, S., Boivin, L. & Nuss, M. C. T-ray tomography. Opt. Lett. 22, 904–906 (1997).

    ADS  Google Scholar 

  36. 36

    Yasuda, T., Yasui, T., Araki, T. & Abraham, E. Real-time two-dimensional terahertz tomography of moving objects. Opt. Comm. (in the press).

  37. 37

    Lee, A. W. M., Williams, B. S., Kumar, S., Hu, Q. & Reno, J. L. Real-time imaging using a 4.3-THz quantum cascade laser and a 320 × 240 Microbolometer Focal-Plane Array. IEEE Photon. Technol. Lett. 18, 1415–1417 (2006).

    ADS  Google Scholar 

  38. 38

    Kim, S. M. et al. Biomedical terahertz imaging with a quantum cascade laser. Appl. Phys. Lett. 88, 153903 (2006).

    ADS  Google Scholar 

  39. 39

    Wang, K., Mittleman, D. M., van der Valk, N. C. J. & Planken, P. C. Antenna effects in terahertz apertureless near-field optical microscopy. Appl. Phys. Lett. 85, 2715–2717 (2004).

    ADS  Google Scholar 

  40. 40

    Chen, H.-T., Kersting, R. & Cho, G. Terahertz imaging with nanometer resolution. Appl. Phys. Lett. 83, 3009–3011 (2003).

    ADS  Google Scholar 

  41. 41

    Tonouchi, M., Yamashita, M. & Hangyo, M. Terahertz radiation imaging of supercurrent distribution in vortex-penetrated YBa2Cu3O7-δ thin film strips. J. Appl. Phys. 87, 7366–7375 (2000).

    ADS  Google Scholar 

  42. 42

    Kiwa T., Tonouchi, M., Yamashita, M. & Kawase, K. Laser terahertz-emission microscope for inspecting electrical faults in integrated circuits. Opt. Lett. 28, 2058–2060 (2003).

    ADS  Google Scholar 

  43. 43

    Inoue, R., Uchida, N. & Tonouchi, M. Scanning probe laser terahertz emission microscopy system. Jpn J. Appl. Phys. 45, L824–826 (2006).

    ADS  Google Scholar 

  44. 44

    Clery, D. Terahertz on a chip. Science 297, 763 (2002).

    Google Scholar 

  45. 45

    Nagel, M., Haring Bolivar, P., Brucherseifer, M. & Kurz, H. Integrated THz technology for label-free genetic diagnostics. Appl. Phys. Lett. 80, 154–156 (2002).

    ADS  Google Scholar 

  46. 46

    Woodward, R. M. et al. Terahertz pulse imaging in reflection geometry of human skin cancer and skin tissue. Phys. Med. Biol. 47, 3853–3863 (2002).

    Google Scholar 

  47. 47

    Yamashita, M., Kawase, K., Otani, C., Nikawa, K. & Tonouchi, M. in Conf. Optical Terahertz Science and Technology doc ID: TuC4 (Florida, USA, 2005).

    Google Scholar 

  48. 48

    Fischer, B. M. et al. Terahertz time-domain spectroscopy and imaging of artificial RNA. Opt. Express 13, 5205–5215 (2005).

    ADS  Google Scholar 

  49. 49

    Walther, M., Fischer, B. M. & Jepsen, P. U. Noncovalent intermolecular forces in polycrystalline and amorphous saccharides in the far infrared. Chem. Phys. 288, 261–268 (2003).

    Google Scholar 

  50. 50

    Whitmire, S. E. et al. Protein flexibility and conformational state: A comparison of collective vibrational modes of wild-type and D96N Bacteriorhodopsin. Biophys. J. 85, 1269–1277 (2003).

    ADS  Google Scholar 

  51. 51

    Chen, J.-Y., Knab, J. R., Cerne, J. & Markelz, A. G. Large oxidation dependence observed in terahertz dielectric response for cytochrome c. Phys. Rev. E 72, 040901 (2005).

    ADS  Google Scholar 

  52. 52

    Nagai, N., Kumazawa, R. & Fukasawa, R. Direct evidence of inter-molecular vibrations by THz spectroscopy. Chem. Phys. Lett. 413, 495–500 (2005).

    ADS  Google Scholar 

  53. 53

    Taday, P. F., Bradley, I. V., Arnone, D. D. & Pepper, M. Using terahertz pulse spectroscopy to study the cryastalline structure of a drug: A case study of the polymorphs of ranitidine hydrochloride. J. Pharm. Sci. 92, 831–838 (2003).

    Google Scholar 

  54. 54

    Kumazawa, R., Toriumi, Y., Shigemoto, I. & Fukasawa, R. in Ext. Abs. Int. Work. Terahertz Technology 17PS-27 (Osaka, 2005).

    Google Scholar 

  55. 55

    Hirori, H., Yamashita, K., Nagai, M. & Tanaka, K. Attenuated total reflection spectroscopy in time domain using terahertz coherent pulses. Jpn J. Appl. Phys. 43, L1287–L1289 (2004).

    ADS  Google Scholar 

  56. 56

    Nagai, M., Yada, H., Arikawa, T. & Tanaka, K. Terahertz time-domain attenuated total reflection spectroscopy in water and biological solution. Int. J. Infrared Milli. Waves 27, 505–515 (2006).

    ADS  Google Scholar 

  57. 57

    Nagai, N., Sumitomo, M., Imaizum, M. & Fukasawa, R. Characterization of electron- or proton-irradiated Si space solar cells by THz spectroscopy. Semicond. Sci. Technol. 21, 201–209 (2006).

    ADS  Google Scholar 

  58. 58

    Nagai, N., Imai, T., Fukasawa, R., Kato, K. & Yamauchi, K. Analysis of the intermolecular interaction of nanocomposites by THz spectroscopy. Appl. Phys. Lett. 85, 4010–4012 (2004).

    ADS  Google Scholar 

  59. 59

    Nagai, N. & Fukasawa, R. Abnormal dispersion of polymer films in the THz frequency. Chem. Phys. Lett. 388, 479–482 (2004).

    ADS  Google Scholar 

  60. 60

    Misra, M., Kotani, K., Kawayama, I., Murakami, H. & Tonouchi, M. Observation of TO1 soft mode in SrTiO3 films by terahertz time domain spectroscopy. Appl. Phys. Lett. 87, 182909 (2004).

    ADS  Google Scholar 

  61. 61

    Nashima, S., Morikawa, O., Takata, K. & Hangyo, M. Temperature dependence of optical and electronic properties of moderately doped silicon at terahertz frequencies. J. Appl. Phys. 90, 837–842 (2001).

    ADS  Google Scholar 

  62. 62

    Mitttleman, D. M., Cunningham, J., Nuss, M. C. & Geva, M. Noncontact semiconductor wafer characterization with the Hall effect. Appl. Phys. Lett. 71, 16–18 (1997).

    ADS  Google Scholar 

  63. 63

    Zhong, H. et al. Nondestructive defect identification with terahertz time-of-flight tomography. IEEE Sensors J. 5, 203–208 (2005).

    ADS  Google Scholar 

  64. 64

    Kawase, K., Ogawa, Y., Watanabe, Y. & Inoue, H. Non-destructive terahertz imaging of illicit drugs using spectral fingerprints. Opt. Express 11, 2549–2554 (2003).

    ADS  Google Scholar 

  65. 65

    Zhong, H., Karpowicz, N. & Zhang, X.-C. Terahertz emission profile from laser-induced air plasma. Appl. Phys. Lett. 88, 261103 (2006).

    ADS  Google Scholar 

  66. 66

    Hirata, A. et al. 120-GHz-band millimeter-wave photonic wireless link for 10-Gb/s data transmission. IEEE Trans. Microwave Theory Technol. 54, 1937–1944 (2006).

    ADS  Google Scholar 

  67. 67

    Akaike, H. et al. Demonstration of a 129GHz single-flux-quantum shift register circuit based on a 10kA cm−2 Nb process. Supercond. Sci. Technol. 19, S320–S324 (2006).

    Google Scholar 

  68. 68

    Akiyama, T. et al. 1.55-μm Picosecond all-optical switching by using intersubband absorption in InGaAs–AlAs–AlAsSb coupled quantum wells. IEEE Photon. Tech. Lett. 14, 495–497 (2002).

    ADS  Google Scholar 

  69. 69

    Kosugi, T., Tokumitsu, M., Enoki, T., Muraguchi, M., Hirata, A. & Nagatsuma, T. in Tech. Dig. IEEE Comp. Semicond. Integ. Circuit Symp. 171–174 (2004).

    Google Scholar 

  70. 70

    Krumbholz, N. et al. Omnidirectional terahertz mirrors: A key element for future terahertz communication systems. Appl. Phys. Lett. 88, 202905 (2006).

    ADS  Google Scholar 

  71. 71

    Kleine-Ostmann, T., Dawson, P., Pierz, K., Hein, G. & Koch, M. Room-temperature operation of an electrically driven terahertz modulator. Appl. Phys. Lett. 84, 3555–3557 (2004).

    ADS  Google Scholar 

  72. 72

    Wang, K. & Mittleman, D. M. Metal wires for terahertz wave guiding. Nature 432, 376–379 (2004).

    ADS  Google Scholar 

  73. 73

    Deibel, J. A., Wang, K., Escarra, M. D. & Mitttleman, D. M. Enhanced coupling of terahertz radiation to cylindrical wire waveguides. Opt. Express 14, 279–290 (2006).

    ADS  Google Scholar 

  74. 74

    Waters, J. W. et al. The earth observing system microwave limb sounder (EOS MLS) on the aura satellite. IEEE Trans. Geosci. Remote Sensing 44, 1075–1092 (2006).

    ADS  Google Scholar 

  75. 75

    Doi, Y. et al. Large-format and compact stressed Ge:Ga array for the ASTRO-F (IRIS) mission. Adv. Space Res. 30, 2099–2104 (2002).

    ADS  Google Scholar 

  76. 76

    Fujiwara, M. et al. Development of Ge:Ga far-infrared photoconductor direct hybrid 2D array. Appl. Opt. 42, 2166–2173 (2003).

    ADS  Google Scholar 

  77. 77

  78. 78

    Orenstein, J., Corson, J., Oh, S. & Eckstein, J. N. Superconducting fluctuations in Bi2Sr2Ca1–xDyxCu2O8+ δ as seen by terahertz spectroscopy. Ann. Phys. 15, 596–605 (2006).

    Google Scholar 

  79. 79

    Kida, N., Murakami, H. & Tonouchi, M. Terahertz Optics in Strongly Correlated Electron Systems in Terahertz Optoelectronics (ed. K. Sakai) 271–330 (Springer, Berlin, 2003).

    Google Scholar 

  80. 80

    Takahashi K., Kida, N. & Tonouchi, M. Terahertz radiation by an ultrafast spontaneous polarization modulation of multiferroic BiFeO3 thin films. Phys. Rev. Lett. 96, 117402 (2006).

    ADS  Google Scholar 

  81. 81

    Beaurepaire, E. et al. Coherent terahertz emission from ferromagnetic films excited by femtosecond laser pulses. Appl. Phys. Lett. 84, 3465–3467 (2004).

    ADS  Google Scholar 

  82. 82

    Tilborg, J. et al. Temporal characterization of femtosecond laser-plasma-accelerated electron bunches using terahertz radiation. Phys. Rev. Lett. 96, 014801 (2006).

    ADS  Google Scholar 

  83. 83

    Huber, R. et al. Femtosecond formation of coupled phonon-plasmon modes in InP: Ultrabroadband THz experiment and quantum kinetic theory. Phys. Rev. Lett. 94, 027401 (2005).

    ADS  Google Scholar 

  84. 84

    Jian, Z., Pearce, J. & Mittleman, D. M. Characterizing individual scattering events by measuring the amplitude and phase of the electric field diffusing through a random medium. Phys. Rev. Lett. 91, 033903 (2003).

    ADS  Google Scholar 

  85. 85

    Jian, Z. & Mitttleman, D. M. Broadband group-velocity anomaly in transmission through a terahertz photonic crystal slab. Phys. Rev. B 73, 115118 (2006).

    ADS  Google Scholar 

  86. 86

    Agrawal, A. & Nahata, A. Time-domain radiative properties of a single subwavelength aperture surrounded by an exit side surface corrugation. Opt. Express 14, 1973–1981 (2006).

    ADS  Google Scholar 

  87. 87

    Zhao, Y. & Grischkowsky, D. Terahertz demonstrations of effectively two dimensional photonic bandgap structures. Opt. Lett. 31, 1534–1536 (2006).

    ADS  Google Scholar 

  88. 88

    Padilla, W. J., Taylor, A. J., Highstrete, C., Lee, M. & Averitt, R. D. Dynamical electric and magnetic metamaterial response at terahertz frequencies. Phys. Rev. Lett. 96, 107401 (2006).

    ADS  Google Scholar 

  89. 89

    kushima K. et. al. Photon-counting microscopy of terahertz radiation. Appl. Phys. Lett. 88, 152110 (2006).

    ADS  Google Scholar 

  90. 90

    Larrabee, D. C. et al. Application of terahertz quantum-cascade lasers to semiconductor cyclotron resonance. Opt. Lett. 29, 122–124 (2004).

    ADS  Google Scholar 

  91. 91

    Suzuki, M., Tonouchi, M., Fujii M., Ohtake, H. & Hirosumi, T. Excitation wavelength dependence of terahertz emission from semiconductor surface. Appl. Phys. Lett. 89, 091111 (2006).

    ADS  Google Scholar 

  92. 92

    Yoshimura, M. et al. in Ext. Abs. Int. Work. Terahertz Technology 17PS-24 (Osaka, 2005).

    Google Scholar 

  93. 93

    Tani, M., Lee, K.-S & Zhang, X.-C. Detection of terahertz radiation with low-temperature-grown GaAs based photoconductive antenna using 1.55 μm probe. Appl. Phys. Lett. 77, 1396–1398 (2000).

    ADS  Google Scholar 

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I am grateful to the research committee member who helped to compile this research report on the current status and prospects of terahertz technology. I also thank Qing Hu, Kodo Kawase, Koichiro Tanaka, Masaya Nagai, Iwao Hosako, Alfred Leitenstorfer, Sushil Kumar, Rupert Huber, Ryoichi Kumazawa, Akihiko Hirata and Norihisa Hiromoto for providing their figures and information.

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Tonouchi, M. Cutting-edge terahertz technology. Nature Photon 1, 97–105 (2007).

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