MODELING HARMONIC-GENERATION BY A DEGENERATE 2-LEVEL ATOM

An analytical theory of the generation of high-order harmonics of lase r radiation has been developed on the basis of a two-level model atom with degenerate levels. Among other parameters, onset, width, and cuto ff of the plateau in the harmonic spectrum are obtained in simple anal ytical forms that connect the basic problem parameters and permit a tr ansparent interpretation of the mechanism underlying the spectrum form ation far this specific case. Selected numerical calculations are repo rted to corroborate the analytical findings and to investigate other h armonic-spectrum features. (C) 1996 Optical Society of America