Number 94 (Story #3), September 16, 1992 by Phillip F. Schewe and Ben Stein|
SOFT X-RAY LASERS ARE NOW OPERATING AT SATURATION , a condition in which the laser's output intensity increases linearly with the length of the lasing medium, in this case a column of high-temperature, high-density plasma. The availability of such lasers would be important in such fields as biological microscopy and holography, but progress has been slow because it is difficult to achieve a high electron temperature and density in a plasma larger than about 1 cm. Two groups have succeeded in reaching saturation. A Rutherford/Oxford/York/Essex/Hull/Belfast/Paris collaboration has used a germanium plasma to produce light at a wavelength of 23.6 nm (A. Carillon et al., Phys. Rev. Lett., 11 May 1992). A Livermore/LBL team has produced 20.6 nm light in a selenium plasma (J.A. Koch et al., Phys. Rev. Lett., 1 June).