Investigation of an optical-field-ionized oxygen plasma for a table-top soft X-ray laser

Abstract

We have experimentally investigated an optical-field-ionized oxygen plasma produced by using a femtosecond terawatt laser in a low-density gas cell. The feasibility of soft X-ray lasing to the ground state in O III has been examined. The lasing line candidate corresponding to the O III 2p(2) ((3)p) - 2p3s ((3)p) transition at 37.41 nm has been observed as being anomalously strong; however, amplification has not; been confirmed yet. The issues that may be essential for the performance of this X-ray laser scheme are discussed.