Abstract: A post-growth optical afterheater system includes an appropriate choice of optical heat source for the single crystal material to be heated, a power adjustment module for controlling the optical power heating the crystal, and suitable focusing optics to focus the heating beam onto the crystal. The heat source may be a laser of appropriate wavelength or an incoherent source of sufficient power. In one embodiment, the power adjustment module is an optical attenuator, either of crossed-polarizer design or of intersecting wire grids. The focusing optics may be refractive, reflective, or catadioptric, depending on factors such as diameter, cost target, and space available in the crystal growth apparatus.