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L. Ren 1, C. L. Pint 2, A. K. W?jcik 3, T. Arikawa 1, Y. Takemoto 4, K. Takeya 4, I. Kawayama 4, A. A. Belyanin 3, M. Tonouchi 4, R. H. Hauge 2, and J. Kono 1*
1 Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
2 Department of Chemistry, Rice University, Houston, Texas 77005, USA
3 Department of Physics, Texas A&M University, College Station, Texas 77843, USA
4 Institute of Laser Engineering, Osaka University, Yamadaoka 2-6, Suita, Osaka 565-0871, Japan
*1 Email: kono@rice.edu
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Abstract: This paper summarizes our recent advances in the spectroscopy of single-walled carbon nanotubes (SWNTs) in the terahertz (THz) range. Using polarization-dependent time-domain THz spectroscopy, we have studied the anisotropic conduction properties of free carriers in a thin film of highly aligned SWNTs. When the THz polarization was parallel to the nanotube alignment direction, there was strong absorption, while virtually no absorption was observed when the THz polarization was perpendicular to the nanotube axis. Through a proper model, the THz complex dynamic conductivity of the SWNTs was extracted and showed a non-Drude-like frequency dependence, with the real part monotonically increasing with increasing frequency and exhibiting a peak around 4.5 THz. Furthermore, the reduced linear dichroism was calculated to be 3, which demonstrates the nematic order parameter to be 1. This indicates that the alignment of the nanotubes is "perfect" and any misalignment must have characteristic length scales much smaller than the wavelengths used in these experiments (1.5 mm – 150 μm)..
Keywords: Terahertz spectroscopy, Carbon nanotubes, Dynamic conductivity, Anisotropy.
Published: 2010-3-30
Acknowledgments: This work was supported by the National Science Foundation (through Grant No. OISE-0530220), the Department of Energy (through Grant No. DEFG02-06ER46308), and the Robert A. Welch Foundation (through Grant No. C-1509).
Cite this article:
L. Ren, C. L. Pint, A. K. W?jcik, T. Arikawa, Y. Takemoto, K. Takeya, I. Kawayama, A. A. Belyanin, M. Tonouchi, R. H. Hauge, and J. Kono. Anisotropic Terahertz Dynamics of Highly-Aligned Single-Walled Carbon Nanotubes[J]. International Journal of Terahertz Science and Technology, 2010, Vol.3, No.1: 26-32. DOI:10.11906/TST.026-032.2010.03.03
URL: http://www.tstnetwork.org/10.11906/TST.026-032.2010.03.03
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