Singlet-singlet singlet-triplet and triplet-triplet transitions for F3+ color centers in LiF crystals

摘要

Abstract: New spin-triplet electronic states of laser-active F$- 3$/$+$PLU$/ color centers in LiF crystals are discovered. The triplet-triplet absorption spectra from low laying $+3$/E state to the high laying states, triplet-triplet $+3$/T$-$alpha$/ $YLD $+3$/E fluorescence spectrum and $+3$/E $YLD $+1$/A$-1$/ triplet-singlet phosphorescence spectrum are measured. Temperature dependencies of nonradiative singlet-triplet $+1$/E $YLD $+3$/E and triplet- singlet $+3$/E $YLD $+1$/A$-1$/ transitions probability are found. The influence of spin-triplet states on the LiF:F$- 3$/$+$PLU$/ color center laser characteristics is discussed. The new way of obtaining of tunable oscillation in wide visible range using triplet-triplet transition is offered. !14