Giant Optical Anisotropy in a Covalent Molybdenum Tellurite via Oxyanion Polymerization (Adv. Sci. 12/2024)

Optical Anisotropy In article number 2306670 by Chao Wu, Mark G. Humphrey, Chi Zhang, and co-workers, a covalent molybdenum tellurite Mo(H2O)Te2O7 (MTO), which exhibits a significantly large experimental birefringence – the largest value for inorganic UV-transparent oxides, has been successfully constructed by an oxyanion polymerization strategy. In the cover, the crystalline MTO in the tetragonal system combines the [TeO3]2• and [TeO4]4• NLO-active units in the polytellurite oxyanion [Te8O20]8•, which maintains an almost coplanar arrangement by linking with [MoO6]6• polyhedra, leading to the generation of strong optical anisotropy. When a beam of red laser light with a wavelength of 1064 nm irradiates the large-birefringence crystal MTO, two beams of strong green laser light (one nonlinear and one linear lights) with a wavelength of 532 nm are generated, which may launch a new perspective for the development of high-performance next-generation birefringent crystalline materials.