A NEW-TYPE ULTRAVIOLET SHG CRYSTAL——β-BaB2O4

On the basis of our work "An anionic group theory of electro-optical and nonlinear optical effects of the crystals", we first proposed the possibility of searching for new-type SHG crystals among the inorganic materials possessing planar ring groups. Since then, a new-type ultraviolet StIG crystal—β-BaBOhas been developed, a crystal with excellent optical homogeneity, anti-deliquescence and easy-working mechanical properties. Various measurements have been made thereupon of its powder sample tests, phase diagram, structural determination and other performance tests. The following parameters of β-BBOhave thus been determined: space group at room temperature R3, melting point 1095℃, phase transition temperature 925±5℃, transparent band range 190—2500mμ, phase matching angle at 539—270mμ 47°, and radiation damage threshold 2GW/em~2. Its effective SHG coefficient is 3—6 times larger than that of ADP (at different wavelengths). It is expected that this new crystal will find wide and e