TERACAN · Terahertz applications of carbon-based nanostructures

Terahertz applications of carbon-based nanostructures

The project joins two different important fields of modern physics and technology: the first one is devoted to studies of carbon-based nanostructures, the second deals with generation and detection of electromagnetic waves in the terahertz (THz) frequency range. The main goal of this interdisciplinary theoretical research was to combine the efforts of four scientific teams from Western and Eastern Europe in the development of a physical basis for a new generation of THz devices based on carbon nanotube (CNT)s and graphene. In order to reach this aim, the following objectives were planned to be accomplished: - to develop fundamentals of THz response properties of finite-length single and multi-wall CNTs, CNT ropes and graphene; - to reveal and analyse different physical mechanisms and conditions of the THz emission from the CNTs and graphene; - to create a theoretical basis for using CNTs and graphene as detectors of THz radiation. Since the beginning of the project, the work was performed in accordance with the work plan distributed between four work packages (WP): 1. linear electromagnetic response of the CNT-based composites in the THz range; 2. CNT-based Cherenkov-type emitters for the THz range; 3. THz emitters and detectors based on CNTs; 4. THz applications of graphene. Within the WP1, the main efforts were directed to the elaboration of the theory of polarisability of a finite-length multi-wall CNT in THz range, the theory of linear CNT-based composites with given orientation statistics and CNT length distribution, the theory of CNT-based composites with resonant-type coherent thermal THz emission and the elaboration of the physical basis for THz applications of novel CNT-based composites and metamaterials. Within the WP2, the theory of linear stage of the Cherenkov instability development in different single-wall CNTs has been elaborated, the modelling of the CNT instability for different CNTs has been carried out, the analysis of possible experimental schemes for the observation of the found effects has been performed and the theoretical models of CNT-based active THz nanodevices were elaborated. Within WP3, we formulated and justified several proposals utilising unique electronic properties of CNTs for a broad range of applications to THz optoelectronics, including THz generation by hot electrons in quasi-metallic CNTs and THz radiation detection by armchair CNTs in a strong magnetic field. Moreover, we elaborated the theory of the THz emission from CNTs in the presence of a magnetic field and the theory of THz Bloch oscillations in chiral CNTs. Within the WP4, the theory of a THz filter based on bilayer graphene, the theory of the THz absorption in graphene p-n junction, the theory of a THz filter based on bilayer graphene and the theory of the THz absorption in graphene p-n junctions were elaborated. The collaboration between scientists from nanostructure and electromagnetic communities lies at the core of the project. In the course of the project, this collaboration helped to develop a novel research discipline with a significant predictive potential, nanoelectromagnetics - a conceptual response to new requirements of the nanoscience development. Indeed, a convergence of the two research communities - the condensed matter nanostructure community, which traditionally works in nanoscience, and the electromagnetic community, which moves inevitably into terahertz and optical frequency ranges using nanostructures, is evident as a new tendency. Following this tendency, the project supplies to the 'research market' a new scientific language for describing electromagnetic phenomena in novel carbon-based nanostructures, which is extremely important for both communities.

Data: CORDIS, © European Union