Nanowerk February 10, 2022 An international team of researchers (Russia, Finland) studied carbon nanotube films conductivity in the terahertz and infrared bands. Some of the films were made of nanotubes with lengths varying from 0.3 to 13 µm, while others were treated with oxygen plasma for 100 to 400 seconds and changed their electrodynamic properties in the process. They discovered that shortening tubes length (down to 0.3 µm) or exposing films to plasma (for longer than 100 s) leads to a drop in conductivity at low terahertz frequencies (< 0.3 THz). Exposure to plasma results in a larger number of […]
Tag Archives: Terahertz spectroscopy
Researchers develop broadband spintronic-metasurface terahertz emitters with tunable chirality
Phys.org October 26, 2021 Researchers in China made laser-driven terahertz emitters, consisting of metasurface-patterned magnetic multilayer heterostructures that can overcome the shortcomings of the conventional approaches. They have demonstrated the efficient generation and manipulation of broadband chiral terahertz waves. The emitter’s ellipticity can reach >0.75 over a broad terahertz bandwidth (1 to 5 THz), it is an efficient source for few-cycle circularly polarized terahertz pulses with stable carrier waveforms, and has flexible control of ellipticity and helicity. They have shown that the terahertz polarization state is dictated by the interplay between laser-induced spintronic-origin currents and the screening charges/currents in the […]