title: Coupling of counterpropagating light beams in low-symmetry crystals.
abstract: Two-beam coupling gain enhancement is demonstrated for a nontraditional orientation of counterpropagating waves in the monoclinic crystal Sn2P2S6.
authors.affiliation: Institute of Physics, National Academy of Sciences, Kyiv, Ukraine. shumeluk@iop.kiev.ua
authors.forename: Alexandr
authors.initials: A
authors.lastname: Shumelyuk
authors.forename: Serguey
authors.initials: S
authors.lastname: Odoulov
authors.forename: Gary
authors.initials: G
authors.lastname: Cook
authors.forename: Dean R
authors.initials: DR
authors.lastname: Evans