Relativistic high-order harmonics of a hydrogenlike atom in an ultrastrong laser field

The relativistic high-order harmonics of a hydrogenlike atom in an ultrastrong laser field has been simulated by the classical Monte-Carlo method in this paper. The results concerning the influence of the laser parameters (frequency, pulse-shape, intensity, etc.) on the elativistic high-order harmonics have been obtained and the conversion efficiency has also been alculated. Some conclusions are drawn and discussed.