Progress With Gain Measurements In Li-Like Ions At 15.4 Nm (A1XI) And 12.9 Nm (SiXII)

Abstract

The sequence of Li-like ions represents an attractive avenue to progress to laser action at soft X-ray wavelengths shorter than those of current X-ray lasers1,2 (see also Refs. 3-6). We are exploring the possibilities for laser action at 15.4 nm in Li-like A1XI and 12.9 nm in Li-like SiXII in a magnetically confined recombining plasma. A ti 1 kJ CO2 laser is focussed onto an aluminum or silicon target assembly and the resulting plasma confined in a solenoidal magnetic field of up to 90 kG. This approach is similar to our previous work on hydrogen-like carbon, CVI, which led to lasing action on the n = 3 to m = 2 transition at 18.2 nm. For lithium-like ions we measure a maximum gain-length (gL) on the 4f-3d transition, of gL Rs 3-4 at 15.4 nm and gL % 1-2 at 12.9 nm. The 18.2 nm laser has been applied to microscopy and first results from a soft X-ray laser microscope are presented.