METHOD OF OBTAINING A MEDIUM HAVING A NEGATIVE ABSORPTION COEFFICIENT IN THE X-RAY AND ULTRAVIOLET SPECTRAL RANGE AND A LASER FOR PRACTICAL APPLICATION OF SAID METHOD

摘要

A plasma is formed from a material in which the ions possess discrete metastable energy states interacting with the energy states of the continuum which are populated by the free electrons of the plasma. Population inversion is achieved between a number of these metastable states and states of lower energy, negative absorption being then produced for the transition which couples the metastable states with said states of lower energy.