There are several experimental reports claiming to have demonstrated amplification and lasing at 13.5 nm on the Lyman - α transition in Li2+ ions produced by optical field ionization (OFI) of a preformed Li-plasma. We have systematically studied properties of Li-OFI-plasmas by recording simultaneously the time dependent XUV line emission and scattered femtosecond laser signals. Our investigations demonstrate that in the Li vapor (plasma) produced by nanosecond pulse laser ablation of a solid target clusters and microparticles are present that strongly influence the XUV emission. These observations raise doubts on the interpretation of so far reported results on the feasibility of the Lyman - α Li laser.
ASJC Scopus subject areas
- Physics and Astronomy(all)