Spectral-luminescent properties of Yb$^{3+}$ in aprotic inorganic liquids POCl$_{3}$–ZrCl$_{4}$

Spectra of absorption and luminescence, the lifetime of Yb$^{3+}$ in room-temperature solutions, along with spectra of luminescence of samples cooled down to 78 K, are acquired. Information on Stark splitting of levels, absorption and stimulated-emission cross sections of Yb$^{3+}$ in POCl$_{3}$–ZrCl$_{4}$ is obtained. The possibility of creating a laser based on inorganic liquid POCl$_{3}$–ZrCl$_{4}$ is evaluated.