A Reel-Wound Carbon Nanotube Polarizer for Terahertz Frequencies

Abstract

Utilizing highly oriented multiwalled carbon nanotube aerogel sheets, we fabricated micrometer-thick freestanding carbon nanotube (CNT) polarizers. Simple winding of nanotube sheets on a U-shaped polyethylene reel enabled rapid and reliable polarizer fabrication, bypassing lithography or chemical etching processes. With the remarkable extinction ratio reaching ∼37 dB in the broad spectral range from 0.1 to 2.0 THz, combined with the extraordinary gravimetric mechanical strength of CNTs, and the dispersionless character of freestanding sheets, the commercialization prospects for our CNT terahertz polarizers appear attractive.

Quasi-optical terahertz polarizers enabled by inkjet printing of carbon nanocomposites

“…[8][9][10] In addition, polarizers based on highly aligned single-walled carbon nanotube (SWNT) films (either on substrates or free-standing) have been demonstrated to have promising performance in the THz region. 11,12 However, the available approaches either require complex (i.e., costly) or chemically aggressive fabrication steps, or are hindered by limitations in carbon nanotube film formation, growth, and transfer. Due to the above, existing approaches limit the choice of substrates and are frequently detrimental to the environment by generating hazardous waste.…”

Anisotropic light transmission of aligned carbon nanotube sheets coated substrates

“…Lei Ren et al reported a highly aligned SWCNT film of a thickness of 2 micrometers, deposited on a sapphire substrate, transparent to terahertz (THz) radiation polarized perpendicular to the nanotube axis with an extinction ratio of about 10dB [4]. Later, Kyoung et al, by winding MWCNT sheets on a U-shaped polyethylene frame, obtained free-standing CNT layers of 9 micrometer thickness with an extinction ratio ~37dB in a spectral region from 0.1-2THz [5].…”

“…Lei Ren et al reported a highly aligned SWCNT film of a thickness of 2 micrometers, deposited on a sapphire substrate, transparent to terahertz (THz) radiation polarized perpendicular to the nanotube axis with an extinction ratio of about 10dB [4]. Later, Kyoung et al, by winding MWCNT sheets on a U-shaped polyethylene frame, obtained free-standing CNT layers of 9 micrometer thickness with an extinction ratio ~37dB in a spectral region from 0.1-2THz [5].Herein we explore the optical properties of highly aligned MWNT sheets on glass substrate in the visible wavelength range finding a clear anisotropy in the optical transmission as an effect of the CNT alignment.Since, CNT sheets are attractive transparent electrodes due to their electrical conductivity and optical transparency, the study of their anisotropic properties and the dependence on the structural organization is of great importance for developing optical devices such as liquid crystal displays. In particular, the quality of the alignment of CNT strands is expected to be relevant for the properties of the sheets since it determines the anisotropy in the characteristics and, as consequence, the performance of the layers in optical devices or as a templating system.…”

Terahertz science and technology of carbon nanomaterials

“…More recently, using extremely well aligned ultralong carbon nanotubes, Ren and co-workers demonstrated that carbon nanotubes can be perfect THz polarizers [60]. Kyoung and co-workers used aligned multi-wall carbon nanotubes to demonstrate similarly strong anisotropy [61].…”