REVIEW OF SOFT-X-RAY LASERS AND THEIR APPLICATIONS

The emerging technology of soft x-ray lasers is in a transition phase between the first laboratory demonstrations of gain and the acceptance of soft x-ray lasers as practical tools for novel applications. Current research is focused on several fronts. The operational wavelength range has been extended to the "water window," important for applications in the life sciences. Gain has also been generated with substantially simpler technology (such as a 6 J laser) and this augurs well for the commercial availability in the near future of soft x-ray lasers for a variety of applications. Advanced soft x-ray laser concepts are being developed from investigations into ultrahigh intensity laser/matter interactions. The first applications of soft x-ray lasers to x-ray microscopy and holography have begun. In this paper a brief historical perspective of x-ray laser development will be followed by a review of recent advances in recombination, collisional, and photopumped systems and applications. A summary of current gain-length performance achieved in laboratories worldwide is presented. Near-term prospects for applications to novel fields are discussed.