Soft‐x‐ray amplification in a capillary discharge plasma

We have realized the first demonstration of large soft‐x‐ray amplification in a discharge‐created plasma. A gain‐length product of g*1=7.2 was measured at 46.9 nm in the J=0‐1 line of Ne‐like Ar in a 12‐cm‐long plasma column generated by compact, fast capillary discharge. The beam divergence was measured to be less than 9 mrad.