Recent progress in capillary discharge soft X-ray lasers

The recent progress in capillary discharge soft X-ray lasers is reviewed. In 1999, a capillary discharge laser operating at 46.9nm produced mJ level pulses at a repetition rate of several Hz. The demonstration of saturated operation of the table-top capillary discharge X-ray laser has opened up a route for the development of table-top X-ray lasers. The fundamental and technical aspects of table-top soft X-ray lasers based on both collisional electron excitation and collisional recombination mechanisms are summarized.