Abstract: A method of forming a carrier wafer includes the steps of: lapping a first surface and a second surface of the carrier wafer such that the carrier wafer is substantially flat, the carrier wafer comprising a glass, glass-ceramic or ceramic material, wherein the carrier wafer has a diameter of from 250 mm to 450 mm and a thickness of from 0.5 mm to 2 mm after lapping; and polishing the first surface of the carrier wafer with at least one of a differential pressure, a differential speed or a differential time between a center portion and an edge portion of the carrier wafer such that the first surface has a convex or concave shape.

Abstract: Optical elements including YbF3 layers with high transmittance in the LWIR spectral range are described. The YbF3 layer is produced by an ion-assisted deposition process under high voltage conditions. Dense, uniform, and nearly defect-free YbF3 layers are formed. The improved material quality of the YbF3 layers leads to low absorption in the LWIR spectral range, especially at wavelengths above 10.0 microns. The extinction coefficient of the YbF3 layers is less than 0.0400 at a wavelength of 13.5 microns.

Abstract: A method of forming a carrier wafer includes the steps of: lapping a first surface and a second surface of the carrier wafer such that the carrier wafer is substantially flat, the carrier wafer comprising a glass, glass-ceramic or ceramic material, wherein the carrier wafer has a diameter of from 250 mm to 450 mm and a thickness of from 0.5 mm to 2 mm after lapping; and polishing the first surface of the carrier wafer with at least one of a differential pressure, a differential speed or a differential time between a center portion and an edge portion of the carrier wafer such that the first surface has a convex or concave shape.