Extreme-ultraviolet harmonic generation near 13 nm with a two-color elliptically polarized laser field

Theoretical results for high-harmonic generation by a two-color ellipticall y polarized laser field are presented. Special emphasis is placed on cohere nt radiation near 13 nm in connection with the development of extreme-ultra violet lithography. Linearly polarized radiation at this wavelength can be obtained with a linearly polarized bichromatic laser field, whereas circula rly polarized radiation can be generated with a bichromatic circularly pola rized field with counterrotating coplanar components. In both cases the har monic emission efficiencies at the saturation intensity are more than 1 ord er of magnitude larger than for harmonic generation with a monochromatic li nearly polarized field. (C) 2000 Optical Society of America OCIS codes: 190 .4160, 190.4180, 270.4180.