Temperature Dependence of the Widths and Positions of the R and N Lines in Heavily Doped Ruby

The widths and positions of the R and N lines in heavily doped ruby have been measured at temperatures from 13° up to 450°K. The results for the temperature dependence of the linewidths are explained in terms of microscopic strains, Raman scattering of phonons by the impurity ions, and direct phonon processes. The results for the lineshifts with temperature are due to the absorption and emission of virtual phonons. A Debye model of phonons is used with different effective phonon distributions for the linewidth and lineshift processes. Also the effective phonon distribution for the broadening of pair (N) lines is different from that for the broadening of single ion (R) lines.