Selfminus;focusing of electromagnetic beams in bismuth

摘要

An intense Gaussian electromagnetic beam propagating through bismuth gives rise to the heating and redistribution of electrons and holes and hence selfminus;induced focusing occurs. At upper microwave frequencies (sim;5000 GHz), the critical power for selfminus;focusing is 0.02 W. At a beam power of 1 W, the focusing length is sim;10 cm. The absorption of the beam in intrinsic bismuth is very small. At strong static magnetic fields (gsim;102kG), modeminus;dependent effects are important.