Temperature effects on the main absorption and emission lines of the Pr^3+:LiYF_4 laser crystal

Abstract

The widths and the shifts of the most important absorption and emission lines observed in the visible, deep-red, and near-infrared spectral domains in the well-known Pr3+-doped LiYF4 laser crystal were measured from 12 to 300 K. The investigated absorption lines are those usually used for laser pumping and are located around 444, 469, and 479 nm, and also around 595 nm. The investigated emission lines are those peaking around 480, 523, 546, 604, 607, 640, 698, 721, 907, and 915 nm. Most of the results are interpreted and successfully described by using the existing linear and quadratic electron–phonon coupling theories. The shape and the temperature evolution of the emission lines occurring around 910 nm are also clearly assigned to a series of spin-allowed and spin-forbidden anti-Stokes emission transitions originating from the thermalization of several emitting energy levels.