title: Nonlinear active materials: an illustration of controllable phase matchability.
abstract: For a crystal to exhibit nonlinear optical (NLO) activity such as second-harmonic generation (SHG), it must belong to a noncentrosymmetric (NCS) space group. Moreover, for these nonlinear optical (NLO) materials to be suitable for practical uses, the synthesized crystals should be phase-matchable (PM). Previous synthetic research into SHG-active crystals has centered on (i) how to create NCS compounds and/or (ii) how to obtain NCS compounds with high SHG efficiencies. With these tactics, one can synthesize a material with a high SHG efficiency, but the material could be unusable if the material was nonphase-matchable (non-PM). To probe the origin of phase matchability of NCS structures, we present two new chemically similar hybrid compounds within one composition space: (I) [Hdpa]2NbOF5·2H2O and (II) HdpaNbOF4 (dpa = 2,2'-dipyridylamine). Both compounds are NCS and chemically similar, but (I) is non-PM while (II) is PM. Our results indicate--consistent with organic crystallography--the arrangement of the organic molecule within hybrid materials dictates whether the material is PM or non-PM.
authors.affiliation: State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, 127 Youyixilu Road, Xi'an 710072, China.
authors.forename: Hongcheng
authors.initials: H
authors.lastname: Lu
authors.forename: Romain
authors.initials: R
authors.lastname: Gautier
authors.forename: Martin D
authors.initials: MD
authors.lastname: Donakowski
authors.forename: T Thao
authors.initials: TT
authors.lastname: Tran
authors.forename: Bryce W
authors.initials: BW
authors.lastname: Edwards
authors.forename: Juan C
authors.initials: JC
authors.lastname: Nino
authors.forename: P Shiv
authors.initials: PS
authors.lastname: Halasyamani
authors.forename: Zhengtang
authors.initials: Z
authors.lastname: Liu
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Poeppelmeier