A composition of matter is provided having the general chemical formula K(H,D)2P(16Ox,18Oy)4, where x 0.002, and x+y≈1. Additionally, a method of fabricating an optical material by growth from solution is provided. The method includes providing a solution including a predetermined percentage of (H,D)216O and a predetermined percentage of (H,D)218O, providing a seed crystal, and supporting the seed crystal on a platform. The method also includes immersing the seed crystal in the solution and forming the optical material. The optical material has the general chemical formula K(H,D)2P(16Ox,18Oy)4, where x 0.002, and x+y≈1.