Abstract

Soft x-ray amplification in collisionally excited Ne-like Ge plasmas has been extensively studied. Gains in excess of 4 cm^–1 have been reported for the 3p-3s transitions. Significant gains have been observed over a wide range of irradiance conditions. The present experiments make use of a novel focusing arrangement^[1] that employs a segmented wedge array (SWA) to overlap several line foci to produce a highly uniform linear plasma. The reproducibility of the XUV spectra was improved allowing gain to be inferred on a core-excited 2s2p⁶3d-2s2p⁶3p J=2-1 transition^[2]. The 3d-2s quadrupole (E2) emission from the upper state of this transition was also identified in the L-shell emission spectrum. These measurements have now been extended into the 60-80 Å region where gain on 2s2p⁶3s-2s²p⁵3s and 2s2p⁶3d-2s²2p⁶3d transitions is expected. Observation of gain on these Ne-like transitions would be significant as it would allow Ne-like lasers to scale to shorter wavelengths, into the "water window".

© 1991 Optical Society of America