Energy transfer and picosecond relaxation of F centers in RbCl, KCl, and KBr.

摘要: Possible decay mechanisms of excited F centers are investigated in both additively colored and x-irradiated RbCl, KCl, KBr, containing typically more than 3\ifmmode\times\else\texttimes\fi{}${10}^{16}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ sizable amounts dimer (${\mathit{F}}_{2}$) higher aggregates. Time-resolved ground-state recovery measurements under F-band excitation at low temperature optical-absorption data show a picosecond deexcitation process, occurring for substantial number possessing shorter times relative concentrations ${\mathit{F}}_{2}$ N centers. This establishes energy transfer from to centers, controversial topic throughout the literature, towards KCl be competitive relaxation channels. Transient absorption heavily by Gadonas et al., which increased transparency ${\mathit{F}}_{2}$-band region 500 ps after pulsed excitation, fully support above conclusion. A similar behavior was also observed RbCl KBr. additional channel could adversely affect laser operation several color-center lasers.