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Terahertz time-domain spectroscopic polarimetry (THz-TDSP) method was used to experimental study polarization properties of unaligned single-wall carbon nanotube thin films with di˙erent geometric parameters on transparent float glass substrates in a frequency range from 0.2 THz to 0.8 THz (corresponding to a wavelength range from ∼1.50 mm to ∼0.37 mm) at a controlled room temperature of 291–293 K, and a relative humidity of 40–45 %. Frequency dependences of azimuth and ellipticity angles of a polarization ellipse (PE) of electromagnetic waves transmitted through the samples, and PEs at the frequencies of 0.2 THz, 0.5 THz, and 0.8 THz were obtained for values of 0.2 Wcm − 2, 0.6 Wcm − 2, and 1.0 Wcm − 2 of an external 980 nm near infrared optical pumping, with an external static magnetic field of ∼0.3 T. Polarization properties were calculated from temporal waveforms of signals transmitted through the samples at the parallel and the crossed by 45° positions to a transmission direction of the polarizers. A change of 15° in the azimuth angle, and of 10° in the ellipticity angle was achieved. The results show that by using carbon nanomaterials-based structures it is possible to devise efficient and affordable magneto-optically tunable polarization modulators that can be used in the advanced areas of terahertz nanoscience and nanotechnologies.

In this work, the conductivity of carbon nanotubes with the different lengths with / without optical pumping in the frequency range of 0.2 - 1 THz was experimentally studied. The results show that the restructuring of the geometric properties of carbon nanotubes will allow to create THz devices with tunable spectral characteristics.

Equivalent complex permittivity of carbon nanotubes (CNT) was measured with/without light illumination at the frequency range of 0.2-1 THz. It was shown that we can tune the dispersion of the CNT c ...