Breakthroughs in photonics 2012: New advances in soft X-ray lasers and applications

This paper reviews the major accomplishments in the development of plasma-based soft X-ray lasers and their applications in 2012. Significant experimental breakthroughs include the extension of the lasing range down to 1.5 nm in an X-FEL photoionized plasma and the 100-Hz operation of a 18.9-nm laser with a record average power of 0.15 mW. New fields of applications, exploiting the high-brightness, coherence, and compactness of the source, were demonstrated. Further breakthroughs toward higher peak power are anticipated from numerical simulations of injection-seeded soft X-ray lasers.