Abstract

Soft X-ray lasers in the 4 - 40 nm region have been an active area of investigation pursued almost concurrently with the development of high power pump lasers. Soft X-ray lasers normally operate in a single pass amplified spontaneous emission mode with large gain coefficients in the 4 - 35 cm¹ range. To achieve stability in output signal these devices are preferably operated in a saturation regime, requiring a gain length product >15. The most robust systems presently use collisional excitation in a plasma column of Ne or Ni-like ions. Lasing action in Ni-like ions is at shorter wavelengths than Ne-like ions but Ni-like schemes require higher pumping powers which previously, almost precluded their study in the UK.

© 1998 IEEE