Belarus State University, Nezavisimosty av. 4, Minsk, Belarus 220030

摘要

The generation of the stimulated radiation by electron beams in nanotubes is predicted. Several basic mechanisms of electrons interaction with electromagnetic wave resulting in the radiative instability can lead to generation. As it has been demonstrated earlier carbon nanotube (CNT) is a slow-wave structure which provides a significant retardation of electromagnetic surface wave (c/v > 100). This surface wave can be synchronized with the electron beam that leads to the Cherenkov radiation mechanism. Another way to develop the electron beam instability is based on the undulator emission mechanism arising due to the interband transitions of electrons moving in nanotube. The dispersion equations of the electron beam instability and threshold conditions for stimulated radiation are derived and studied. The analysis of the threshold conditions shows the possibility of stimulated radiation by electron flow which exists in CNTs when voltage in some volts is applied. The conditions for realization of stimulated radiation in CNT are discussed. Intraband transitions corresponding to Cherenkov instability are studied further in detail.