title: Titanosilicates with Strong Phase-Matched Second Harmonic Generation Responses.
abstract: The search for new and efficient nonlinear optical (NLO) materials has been an active research because of their technological importance in laser applications. Although a large number of frequency-doubling oxides, phosphates, borates, and fluoride-containing borates were found, no transition-metal silicate with useful NLO properties has been reported. We have now synthesized and grown crystals of two new titanosilicates, Li2K4[(TiO)Si4O12] and Li2Rb4[(TiO)Si4O12], by using a flux and supercritical hydrothermal method. Their unique 3D framework structures contain highly compressed TiO5 square pyramids which are arranged one over the other to form infinite ···Ti-O···Ti-O straight chains with alternating short and long Ti-O distances. These two materials meet the requirements for efficient second harmonic generation including lack of center of inversion symmetry, large susceptibility, phase matching, transmitting at wavelengths of interest, resistant to laser damage, and thermally stable. These attributes make them very attractive for frequency-doubling materials.
authors.affiliation: Department of Chemistry, National Central University , Zhongli, Taiwan 320, R.O.C.
authors.forename: Tzu-Ling
authors.initials: TL
authors.lastname: Chao
authors.affiliation: Department of Chemistry, National Central University , Zhongli, Taiwan 320, R.O.C.
authors.forename: Wen-Jung
authors.initials: WJ
authors.lastname: Chang
authors.affiliation: Department of Chemistry, National Central University , Zhongli, Taiwan 320, R.O.C.
authors.forename: Shu-Han
authors.initials: SH
authors.lastname: Wen
authors.affiliation: Department of Chemistry, National Central University , Zhongli, Taiwan 320, R.O.C.
authors.forename: Yu-Qing
authors.initials: YQ
authors.lastname: Lin
authors.affiliation: Department of Chemistry, National Central University , Zhongli, Taiwan 320, R.O.C.
authors.forename: Bor-Chen
authors.initials: BC
authors.lastname: Chang
authors.affiliation: Department of Chemistry, National Central University , Zhongli, Taiwan 320, R.O.C.|Institute of Chemistry, Academia Sinica , Taipei, Taiwan 115, R.O.C.
authors.forename: Kwang-Hwa
authors.initials: KH
authors.lastname: Lii