Demonstration of a hybrid collisional soft-x-ray laser - art. no. 033803

We report on a demonstration of x-ray-ultraviolet amplification following c ollisional excitation in a discharge-created plasma waveguide irradiated by a picosecond optical laser pulse. A capillary discharge was used to genera te a sulfur plasma column with a large concentration of Ne-like ions and a radially concave electron density profile. The intense short laser pulse ra pidly heated the electrons, producing amplification in the 3p S-1(0)-3s P-1 (1) transition of Ne-like S at 60.8 nm. The integrated gain-length product obtained exciting a 3-cm-long capillary with a 0.46-J short laser pulse is 6.8. The beam divergence was observed to decrease as a function of plasma c olumn length, reaching 2.5 mrad for 30-mm-long capillaries. This hybrid las er pumping scheme could lead to a new generation of efficient tabletop soft -x-ray lasers.