Prospects for light amplification in the far ultraviolet (review)

A review is given of theoretical and experimental investigations concerned with the feasibility of light amplification in the far ultraviolet (3–50 nm) due to transitions in multiply charged ions. An analysis is made of the most advanced population inversion methods. Experiments in which population inversion was observed or amplification was achieved are examined. The feasibility of developing short-wavelength lasers utilizing recombination systems similar to those achieved for singly charged ions are discussed.