摘要
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.
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.
基金
Project supported by the National Natural Science Foundation of China (Grant Nos. 10874020 and 11074025)
the National Basic Research Program of China (Grant No. 2011CB922204)
