CASTECH Inc. researches, develops, manufactures, and sells crystals, optics, and laser components primarily in China. The company offers NLO, laser, magneto-optical, birefringent, AO and EO, and scintillation crystals, as well as oven and temperature controller accessories; precision optics, including coatings, windows, mirrors, prisms, lenses, spherical lenses, cylindrical lenses, waveplates, polarizers, beamsplitters, aspherical lenses, diffraction gratings, and featured optics; and laser components, such as magneto-optic, acousto-optic, electro-optic, laser application devices. It also exports its products to North America, Europe, Japan, and other Asian countries. The company was founded in 1988 and is based in Fuzhou, China.