Method for preparing single-crystal cubic sesquioxides and uses

The present invention relates to a process for the preparation of hulk or thin-film single-crystals of cubic sesquioxides (space group No. 206, Ia-3) of scandium, yttrium or rare earth metals doped or not doped with lanthanide ions having a valency of +III by a high-temperature flux growth technique and to the applications of the nondoped single-crystals obtained according to this process, in particular in the optical field.