Terahertz phenomena in the strong coupling regime

• Main Author: Kristinsson, Kristinn
• Other Authors: Ivan Shelykh
• Format: Theses and Dissertations
• Language: English
• Published: 2017
• Subjects: DRNTU::Science::Physics::Optics and light; DRNTU::Science::Physics::Atomic physics::Solid state physics
• Online Access: http://hdl.handle.net/10356/69475
• Institution: Nanyang Technological University

Emission and utilization of terahertz range electromagnetic radiation is an active area of research. This thesis is divided into two main parts, in the first of which a scheme of generation of THz radiation from the dipolariton system is presented. Dipolarions, a form of exciton-polaritons, are hybrid light-matter particles, arising in a semiconductor microcavity with embedded double quantum wells from the strong coupling between the confined photon and spatially direct and indirect excitons. Oscillations between the direct and indirect excitons and associated oscillation in dipole moment is shown to couple to an external THz cavity mode, resulting in coherent THz emission. In the second part of the thesis, the influence of THz radiation on transport properties of graphene is investigated. The Dirac-like nature of the graphene electron has long been of theoretical interest, but only recently observed experimentally. By strongly irradiating the graphene sheet, the electron wave-function is altered by the field, resulting in what is commonly called a “dressed electron”. The dressed graphene is shown to have strongly modified transport properties. Specifically it is shown that with linear polarization of the dressing field there arises a large anisotropy of conductivity between the directions parallel and perpendicular to the polarization direction.