Features of lasing in active media utilizing NaF:Me2+ crystals containing F2+-like centers

A study of NaF crystals doped with bivalent metals Ca, Mg, or Mn revealed the presence of F aggregate centers comprising an F₂ center adjacent to an Me²⁺-υ_c^– impurity-vacancy dipole. Excitation by laser radiation in the absorption band of these centers ionized them to F₂⁺(Me) centers. Efficient lasing tunable within the luminescence band of the F₂⁺(Me) centers was achieved. In this case, the F₂⁺(Me) centers were generated and excited by radiation of the same wavelength (λ = 659 nm). The lasing characteristics of this laser were studied.