In Search of Inorganic Nonlinear Optical Materials for Second Harmonic Generation

✍ Scribed by J. Gopalakrishnan; K. Ramesha; K. Kasthuri Rangan; Sonal Pandey

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 324 KB
• Volume: 148
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8353

✦ Synopsis

In a search for inorganic oxide materials showing secondorder nonlinear optical (NLO) susceptibility, we investigated several borates, silicates, and a phosphate containing trans-connected MO 6 octahedral chains or MO 5 square pyramids, where M ‫؍‬ d 0 : Ti(IV), Nb(V), or Ta(V). Our investigations identi5ed two new NLO structures: batisite, Na 2 Ba(TiO) 2 Si 4 O 12 , containing trans-connected TiO 6 octahedral chains, and fresnoite, Ba 2 TiOSi 2 O 7 , containing square-pyramidal TiO 5 . Investigation of two other materials containing square-pyramidal TiO 5 , viz., Cs 2 TiOP 2 O 7 and Na 4 Ti 2 Si 8 O 22 ' 4H 2 O, revealed that isolated TiO 5 square pyramids alone do not cause a second harmonic generation (SHG) response; rather, the orientation of TiO 5 units to produce +Ti+O+Ti+O+ chains with alternating long and short Ti+O distances in the fresnoite structure is most likely the origin of a strong SHG response in fresnoite.

1999 Academic Press

The structures are drawn from the crystallographic data given in the literature using DIAMOND software.