Terahertz wave generation in coupled quantum dots

Abstract

Based on coupled quantum dots, we present an interesting optical effect in a four-level loop coupled system. Both the two upper levels and the two lower levels are designed to be almost degenerate, which induces a considerable dipole moment. The terahertz wave is obtained from the low-frequency component of the photon emission spectrum. The frequency of the terahertz wave can be controlled by tuning the energy levels via designing the nanostructure appropriately or tuning the driving laser field. A terahertz wave with adjustable frequency and considerable intensity (100 times higher than that of the Rayleigh line) can be obtained. It provides an effective scheme for a terahertz source.

Material growth and device fabrication of terahertz quantum-cascade laser based on bound-to-continuum structure

“…There is a broad range of applications associated with the terahertz (THz) technology. [1,2] But it has historically been characterized by a relative lack of convenient radiation sources and detectors. The THz quantum cascade laser (QCL) is a compact and coherent source in THz region, which is a unipolar device based on inter-subband transitions in the conduction band of a specifically engineered semiconductor heterostructure.…”

Spin-polarized current in double quantum dots

“…And many interesting optical effects have been found in coupled quantum dots. [7,8] The spin degree of freedom of electrons has great potential as a carrier of classical information (spintronics) [9] and quantum information [10,11] (spin quantum bits). Spintronics is a new research area, in which the spin plays an important role in a lot of new physical phenomena.…”