Soft X-ray amplification by Li-like Al10+ and Si11+ ions in recombining plasmas

Experimental studies of soft X-ray lasers were carried out on the six-beam laser facility and the LF 12 laser facility of SIOM. Using a home-made one-dimensional spatially resolved grazing incidence grating spectrograph, XUV amplification has been observed in Li-like aluminum and silicon ions, by irradiation of slab targets with a line-focused laser. Based on time-integrated measurement, gain coefficients are 3.1 cm^–1 for the 105.7 Å 5f–3d transition in Li-like Al ions, and 1.5 cm^–1 and 1.4 cm^–1 for the 88.9 Å 5f–3d and the 87.3 Å 5d–3p transitions in Li-like Si ions, respectively. The maximum gain × length products (GL) are about 2.5.