Tou TY, Ng SW. SHG in a centrosymmetric crystal - can it be possible?
ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2021;
77:586-590. [PMID:
34607980 DOI:
10.1107/s2053229621009293]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/07/2021] [Indexed: 11/10/2022]
Abstract
The present report lists selected publications on centrosymmetric compounds that manifest second harmonic generation responses in a laser, along with a few publications that dispute the laser outcomes. Two studies provide a plausible explanation for this apparent contradiction between second-order nonlinear susceptibility and inversion symmetry: the crystals are noncentrosymmetric and are twinned by inversion. If crystal structures of SHG-active compounds are presented in centrosymmetric settings, the authors of the publications may consider stipulating that the true space group is likely to be one of the noncentrosymmetric sub-space groups.
Collapse