title: Generation of terahertz radiation by optical excitation of aligned carbon nanotubes.
abstract: We have generated coherent pulses of terahertz radiation from macroscopic arrays of aligned single-wall carbon nanotubes (SWCNTs) excited by femtosecond optical pulses without externally applied bias. The generated terahertz radiation is polarized along the SWCNT alignment direction. We propose that top-bottom asymmetry in the SWCNT arrays produces a built-in electric field in semiconducting SWCNTs, which enables generation of polarized terahertz radiation by a transient photocurrent surge directed along the nanotube axis.
authors: †Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.|‡Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, United States.
authors: Lyubov V
authors: LV
authors: Titova
authors: §Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37240, United States.
authors: Cary L
authors: CL
authors: Pint
authors: Qi
authors: Q
authors: Zhang
authors: Robert H
authors: RH
authors: Hauge
authors: Junichiro
authors: J
authors: Kono
authors: †Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
authors: Frank A
authors: FA
authors: Hegmann
keywords: SWCNTs; Single-wall carbon nanotubes; THz pulses; terahertz generation