Crystal growth and annealing method and apparatus

A crystal annealing apparatus suitable for production of a fluoride crystal with minimized residual stress and birefringence, comprising

• a) a support structure;
• b) a movable crucible comprising sides and two ends adapted to contain a crystal within the support structure;
• c) a primary heating system mounted with the support structure proximal the first end and sides of the crucible;
• and
• d) a movable secondary heating system mounted with the support structure proximal the second end of the crucible, wherein the primary heating system and secondary heating system have heating capacities that maintain the crystal temperature uniform to within about 8° C. per inch with said secondary heating system movable with said crucible.

A crystal growth and annealing apparatus, comprising:

• a) a support structure;
• b) a primary heating system mounted with the support structure;
• c) a movable crucible support mounted with the support structure movable between first and second positions;
• d) a movable crucible comprising a liquid phase end adapted to hold liquid crystal material and crystal growth end adapted to hold solid crystal material, mounted with the movable crucible support so that the crystal growth end is proximal the primary heating system when the movable crucible support is in the first position and outside the primary heating system when the movable crucible support is in the second position;
• and
• e) a movable secondary heating system mounted with the crucible support proximal the of the crucible.