Abstract

We show that lasing action in VUV domain can be obtained by pumping Sc IV ions with a Se²⁴⁺ x-ray laser (XRL). This is possible because of the perfect (within the accuracy of the measurement) coincidence between the wavelength 220.28 Å of the transition from the ground level to the level 3s²3p⁵(²P⁰)4d${}^1{\text{P}}_1^0$. in Sc IV ions, as well as favorable ratios of the radiative decay rates of the lower levels. The solution of the rate equations for Sc IV using the incident XRL radiation intensity ≃ 10⁸ W/cm², the electron density ≃ 3 × 10¹⁶ cm^–3, and the plasma temperature ≃ 35 eV yields the small-signal gain coefficients ≃13 cm^–1 and ≃5 cm^–1 for the VUV radiation with the wavelengths 1665.918 Å and 1584.645 Å, respectively, within 1 ns after the XRL pulse.

© 1991 Optical Society of America