Large Diameter Germanium Single Crystals For IR Optics

Large single crystals, up to 8" diameter, of high quality Optical Germanium, have been grown by the Czochralski technique. Post-growth thermal treatment improves the optical homogeneity and reduces optical losses, as shown by refractive index gradients and MTF measurements. A new approach for the piecewise combination of interferograms as well as a polychromatic treatment of MTF, are presented.