Saltiel, SolomonNeshev, DragomirFischer, RobertArie, AdyKrolikowski, WieslawKivshar, Yuri2009-09-222010-12-202009-09-222010-12-20Physical Review Letters 100.10 (2008): 103902/1-40031-90071079-7114http://hdl.handle.net/10440/905http://digitalcollections.anu.edu.au/handle/10440/905We report on the observation of second-harmonic conical waves generated in a novel geometry of the transverse excitation of an annular periodically poled nonlinear photonic structure by a fundamental Gaussian beam. We show that the conical beams are formed as a result of the higher-order nonlinear Bragg diffraction involving two parametric processes in which an ordinary fundamental wave is converted simultaneously into ordinary and extraordinary polarized second harmonics.4 pagesThe author has the right to deposit the final version or the APS-prepared version on the ANU institutional repository as long the author was employed by the ANU when the paper was published and the repository is for the ANU Canberra campus only, not joint with other universities or other entities. (Email from APS, Publications Marketing Coordinator, 30/7/09) Copyright statement: ©2008 The American Physical SocietyKeywords: Excitation energy; Gaussian beams; Harmonic generation; Nonlinear optics; Conical waves; Nonlinear Bragg diffraction; Bragg gratings2008-03-1210.1103/PhysRevLett.100.1039022015-12-08