Spectroscopy ofCr3+in Glasses: Fano Antiresonances and Vibronic "Lamb Shift"

Absorption spectra of ${\mathrm{Cr}}^{3+}$-doped glasses exhibit features which are interpreted as Fano antiresonances resulting from interaction of ${}_{}{}^2{}_{}{}^{}E$ and ${}_{}{}^2{}_{}{}^{}T_1^{}{}_{}{}^{}$ states with a vibrationally broadened ${}_{}{}^4{}_{}{}^{}T_2^{}{}_{}{}^{}$. Inhomogeneous line broadening in glass permits the observation of a shift of sharp levels due to interaction with the quasicontinuum.