Spectral and luminescent properties of Yb$^{3+}$ in CCl$_4$–GaCl$_3$–Yb$^{3+}$ solutions

The absorption and luminescence spectra and the luminescence lifetime of the excited state $^2F_{5/2}$ of Yb$^{3+}$ ions in CCl$_4$–GaCl$_3$–Yb$^{3+}$ solutions have been measured. Information was obtained on the Stark splitting of levels, on the absorption and stimulated emission cross sections, and on the quantum yield of Yb$^{3+}$ luminescence. The spectral dependences of the gain cross section are calculated for different relative inverse populations of the $^2F_{5/2}$ excited state. Based on an analysis of the spectral and laser properties of Yb$^{3+}$, it was concluded that the use of CCl$_4$–GaCl$_3$–Yb$^{3+}$ solutions as the active medium of a liquid ytterbium laser is promising.