Abstract

Recent experiments have revealed longer fluorescence lifetimes for the excited states of tripositve americium in a fluorozirconate glass than have been previously reported in other hosts. In particular, the ⁵D₁¹-to-⁷F₁¹ transition was found to have a lifetime of 1 ms, indicating efficient fluorescence emission. This, together with the energy-level structure, suggests the possibility of using the ⁵D₁¹-to-⁷F₁¹ transition as a four-level laser. A possible complication is the presence of color centers arising from the radioactive decay of Am²⁴³. We will present results of optical gain measurements, and we will report on the variation of lasing threshold and efficiency with ion concentration and excitation configuration if laser action can be demonstrated. The samples will be excited by optical pumping into the ⁵L₆ state at 501 nm; we expect laser action at 695 nm.

© 1990 Optical Society of America