Assessment of Orientational Order in Multilayer Aligned Carbon Nanotubes Using THz and Optical Spectroscopy
Egor A. Chepurov1, Alexander S. Marakulin1, Artur R. Ishteev2, Oksana V. Shapovalova2, Gennadii A. Komandin3, Nikolay V. Pak1, Maria G. Burdanova1; 1Center for Photonics and 2D Materials, MIPT, Phystech; 2Semenov Federal Research Center for Chemical Physics of the Russian Academy of Sciences, Moscow, Russia; 3Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia
Abstract
Aligned carbon nanotube (CNT) films exhibit unique anisotropic optical properties, making them highly promising for applications in photonics and optoelectronics. The electromagnetic response of these films is strongly polarization-dependent across a broad spectral range, from terahertz to visible wavelengths. Based on exciton absorption selection rules and the depolarization effect, significant differences in transmittance were observed for incident beams polarized parallel and perpendicular to the nanotube alignment direction. To quantify alignment quality, an alignment parameter was calculated, ranging from 0.6 to 0.8 depending on sample thickness. A detailed analysis of polarization-angle-dependent attenuation, measured as a function of the angle between the terahertz polarization and the nanotube alignment direction, was conducted at selected wavelengths (510 nm, 580 nm, 650 nm, and 720 nm). The results reveal pronounced polarization-dependent transmission variations, underscoring the potential for developing tailored optical filtering and sensing devices, polarizators. Engineering tunable, broadband, and cost-effective THz devices remains a significant challenge, representing a key bottleneck in fully harnessing the THz spectrum.
Speaker
Chepurov Egor
Center for Photonics and 2D Materials, MIPT, Phystech
Russia
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