Optically driven terahertz wave polarization control by unaligned carbon nanotubes

摘要

Terahertz time-domain spectroscopic polarimetry (THz-TDSP) method was used to experimental study polarization properties of unaligned single-wall carbon nanotube thin films with different geometric parameters on transparent float glass substrates in a frequency range 0.2-0.8 THz at a controlled room temperature of 291-293K, and a relative humidity of 40-45%. Frequency dependences of azimuth and ellipticity angles of a polarization ellipse of electromagnetic waves transmitted through the samples were obtained for values of 0.2-1.0 Wcm~(-2) of an external 980 nm near infrared optical pumping, with an external static magnetic field of ～0.3 T. 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.