Features of YAG crystal growth under Ar+CO reducing atmosphere

• YAG crystals are successfully grown by the Czochralski technique under Ar+CO atmosphere.
• Interaction of the Ar+CO atmosphere with melt and products of its dissociation is considered.
• YAG surface layer is depleted with Al and oxygen under the reducing conditions.
• Thermal annealing procedure to improve YAG crystal transparency is proposed.

The influence of the reducing Ar+CO atmosphere on the stages of starting raw material preparation, growth and post-growth annealing of yttrium aluminum garnet, Y3Al5O12 (YAG) crystals was studied. The chemical reactions involving CO atmosphere and its impact on the raw material, melt, and crystal composition are determined. Modification of YAG optical properties under the reducing annealing is discussed.