Magneto-optic Faraday effect in unaligned single-wall carbon nanotube thin films with different geometric parameters on transparent float glass substrates was experimental studied in a frequency range 0:2–0:8 THz (corresponding to a range from ~1:50mm to ~0:37mm) at a controlled room temperature of 291–293K, and a relative humidity of 40–45%. A change of 15° in an azimuth angle, and of 10° in an ellipticity angle was achieved. The results show that by using carbon nanomaterials-based structures it is possible to devise efficient tunable polarizers that can be used in the advanced areas of terahertz nanophotonics.
Magneto-optic Faraday effect in unaligned single-wall carbon nanotube thin films with different geometric parameters on transparent float glass substrates was experimental studied in a frequency range 0:2–0:8 THz (corresponding to a range from ~1:50mm to ~0:37mm) at a controlled room temperature of 291–293K, and a relative humidity of 40–45%. A change of 15° in an azimuth angle, and of 10° in an ellipticity angle was achieved. The results show that by using carbon nanomaterials-based structures it is possible to devise efficient tunable polarizers that can be used in the advanced areas of terahertz nanophotonics.
Recent years, polarimetry in the terahertz frequency range has gained popularity. Polarimetry is a technique used to measure the polarization state of electromagnetic waves transmitted through samples. The ellipticity angle, the azimuth rotation angle, complex optical properties of materials can be obtained by terahertz timedomain polarimetry. This allows for obtaining more comprehensive information about the object. In this paper, we study diagonal and off-diagonal components of the permittivity tensor of thin bismuth-based films using terahertz time-domain polarimetry
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:.0Wcm-2 of an external 980nm near infrared optical pumping, with an external static magnetic field of ~0:3T. 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.
We propose a modified approach to more detailed study of gyrotropic materials using terahertz (THz) ellipsometry method based on the magneto-optical Kerr effect (MOKE). This approach allows to obtain polarization properties and to calculate the permittivity tensor of materials which are reflective or opaque in THz frequency range. The method allows to measure any values of the diagonal and off-diagonal components of the permittivity tensor and can be used for materials with a strong magneto-optical response.
In this work, we propose and theoretically investigate the first dynamically tunable metasurface based on new twodimensional (2D) material - multi-layer graphene (MLG). As a basis for metasurface development, the results of experimental studies in THz frequency band of 80-layered graphene on dielectric substrate under external optical pumping were used. The metasurface consist of the Polymethylpentene (TPX) substrate and cross-shaped MLG pattern. In addition, the structure of the metasurface is very simple and can be fabricated by chemical vapor deposition and laser engraving. Proposed non-metallic metasurface is high-potential candidate for designing an active THz devises.
In this work, we study infrared optical pump-induced changes in terahertz conductivity of multi-layer graphene on a silicon substrate using terahertz time-domain spectroscopy. Results indicate that the conductivity and optical parameters of investigated material strongly depend on a pumping intensity and the presence of FeCl3 molecules intercalation. The findings are helpful for determining the most optically tunable material towards designing of optically controllable terahertz devices based on new two-dimensional material beyond graphene monolayer.
We propose a high-Q optically tunable terahertz (THz) filter consisting of subwavelength multilayer graphene/ dielectric/metal asymmetric square split-ring resonators (SRR) within a unit cell. The obtained simulation results demonstrate that Fano resonance can be efficiently modulated under IR-radiation of different intensity value. The modulation depth of Fano resonance can achieve about 60% under the maximum considered pumping intensity (corresponding to 0.4 eV of Fermi energy) with the Q-factor of about 135. The proposed metasurface provides narrow filtering of incident light as well as sensing applications.
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