REO offers a range of polarizing beamsplitter cubes that deliver a combination of good optical performance, high laser damage resistance, and good environmental stability and durability. In terms of optical specifications, they deliver a transmitted extinction ratio as high as 10:000:1, while maintaining a transmitted wavefront distortion as low as λ/20 at 633 nm. The cubes are assembled using proprietary Activated Covalent Bonding technology, rather than through adhesive bonding or optical contacting. The elimination of any organics or glues from the beam path yields a high laser damage threshold and avoids internal optical absorption. The cubes are typically available in the 1- to 125-mm size range and are fabricated from either fused silica substrates, for operation in the 266-nm to 2-μm spectral band, or from silicon, for use at wavelengths from 2 to 5 μm. They are suitable for use in cryogenic environments, and for industrial, military and spaceborne applications.