Abstract-Generation of terahertz radiation by optical excitation of aligned carbon nanotubes

Lyubov Titova , Cary L. Pint , Qi Zhang , Robert H. Hauge , Junichiro Kono , and Frank Hegmann

Nano Lett., Just Accepted Manuscript

DOI: 10.1021/acs.nanolett.5b00494

Publication Date (Web): April 16, 2015

Copyright © 2015 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.5b00494

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.