Cooling of optical-field-ionized plasmas

Time-resolved investigations of soft-x-ray radiation from helium and oxygen plasmas produced by optical-field ionization in an intense laser field are performed. The possibility of rapid cooling of these plasmas by metal piec es is studied. It is shown that the time duration of the radiation componen ts produced by three-body recombination pumping can be significantly reduce d in the vicinity of metal surfaces. Soft-x-ray lasing at 37.4 nm in Om ion s with a gain-length product GL similar or equal to 4.4 is demonstrated. [S 1063-651X(99)15102-X].