2007 Fiscal Year Final Research Report Summary
Mutual modulation between terahertz electrical signals and lightwaves in solidstate devices
| Project/Area Number |
17360032
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | Hiroshima University |
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Principal Investigator |
KADOYA Yutaka Hiroshima University, Graduate School of Advanced Sciences of Matter, Professor (90263730)
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| Co-Investigator(Kenkyū-buntansha) |
KITAGAWA Jiro Hinoshima University, Graduate School of Advanced Sciences of Matter, Assistant Professor (90346528)
HOSAKO Iwao National Institute of Information and Communications Tachnology, Advanced Communications Technology Group, Research Manager (00359069)
SEKINE Norihiko National Institute of Information and Communications Technology, Advanced Communications Technology Group, Researcher (10361643)
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| Project Period (FY) |
2005 – 2007
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| Keywords | terahertz / microstrip line / semiconductor quantum well / cascade laser / single wire waveguide / time-domain spectroscopy |
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| Research Abstract |
In this project, we have performed an investigation aiming at the functional devices enabling a control of lightwaves by THz electrical signals and vise versa.
(1) Systematic elucidation of the THz dielectric response and the carrier dynamics of the electrons and holes in semiconductor quantum wells: (1) The characteristics of THz pulses in polymer microstrip lines were clarified. (2) Technology of embedding quantum well thin films in the microstrip lines was developed. (3) The changes of the THz wave propagation by the carriers photo-excited in the quantum wells were clearly detected. (4) It was proven that the THz dielectric response of the quantum confined carriers is a type of polarization, and shown that the relaxation time can be considered to be that of the energy relaxation. (5)The photo-carrier relaxation was detected in the change of the THz pulse propagation.
(2) Modulation of the intensity and the coherent nonlinear response of lightwaves by THz pulses: sufficient results were not obtained.
(3) Modulation of optical response of quantum wells by the CW-THz waves from Quantum cascade lasers (QCLs): We have successfully developed the THz-QCLs based on double-metal waveguide and QCLs of GaSb/AISb systems, which were necessary to obtain low threshold and high intensity output.
(4) Observation of THz pulses in spatial coordinate using a linear response of quantum wells:. With electromagnetic wave simulations on a realistic device structure, we have shown that the observation can be realized.
(5) Elucidation of the propagation characteristics of THz pulses on single conductor wires: The role of the imaginary part of the conductivity in the waveguiding by single wires was clarified. It was also shown that the role shows up in THz regime, which is a crossover between radio- and light-waves.
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