Exploring Structure-Sensitive Factors Relevant to Cryogenic Laser Operation in Oxide Crystals Doped with Er 3+ Ions.

Crystals of Gd 3 Al 2.5 Ga 2.5 O 12 :Er 3+ , (Lu 0.3 Gd 0.7 ) 2 SiO 5 :Er 3+ and LiNbO 3 :Er 3+ compounds differing in origin and the nature of their inherent structural disorder were crystalized. Optical absorption and luminescence spectra for transitions between the 4 I 15/2 and the 4 I 13/2 multiplets of Er 3+ ions for the crystal samples were recorded versus temperatures in the region of 80-300 K. Gathered data were analyzed thoroughly providing the in-depth knowledge of the effects of temperature on intensities, wavelengths and bandwidths of Er 3+ transitions. The information acquired together with the knowledge of significant structural dissimilarities of the host crystals chosen made it possible to propose an interpretation of the impact of a structural disorder in Er 3+ -doped crystals on their spectroscopic properties, and to determine their lasing ability at cryogenic temperatures upon resonant (in-band) optical pumping.