GENERATION OF CIRCULARLY-POLARIZED MULTIPLE HIGH-ORDER HARMONIC EMISSION FROM 2-COLOR CROSSED LASER-BEAMS

We present a scheme for the production of circularly polarized multipl e high-order harmonic generation (HHG). The proposed experimental setu p involves,the use of two-color laser fields, consisting of a circular ly polarized fundamental laser field and a linearly polarized second-h armonic laser field, in crossed-beam configuration. The feasibility of such a scheme is demonstrated by an nb initio quantal study of the HH G power spectrum of He atoms by means of the time-dependent density-fu nctional theory with optimized effective potential and self-interactio n correction recently developed. The theoretical study also provides i nsights regarding the different mechanisms responsible for the product ion of HHG in different energy regimes as well as the mechanism for th e generation of continuous background radiation. [S1050-2947(98)50410- 6].