Patent ID: 7710656

Claim:
A polycrystalline optoceramic comprising single crystallites, wherein at least 95 wt. % of the single crystallites have a cubic pyrochlore or fluorite structure and a 2 mm sample of the optoceramic has a pure transmission of more than 80% in a wavelength range of 600 to 800 nm, and said optoceramic comprises an oxide of stoichiometry: A 2+x B y D z E 7 wherein 0≦x≦1, 0≦y≦2 and 0≦z≦1.6; wherein 3x+4y+5z=8; wherein A is at least one trivalent rare earth cation; B is at least one tetravalent cation; D is at least one pentavalent cation; and E comprises at least one divalent anion.