title: Annular symmetry nonlinear frequency converters.
abstract: We present a new type of two-dimensional nonlinear structure for quasi-phase matching. This structure has continuous rotational symmetry, and in contrary to the commonly used periodic structures, is not lattice shaped and has no translation symmetry. It is shown that this annular symmetry structure possesses interesting phase matching attributes that are significantly different than those of periodic structures. In particular, it enables simultaneous phase-matched frequency doubling of the same pump into several different directions. Moreover, it has extremely wide phase-mismatch tolerance, since a change in the phase matching conditions does not change the second harmonic power, but only changes its propagation direction. Several structures were fabricated using either the indirect e-beam method in LiNbO(3) or the electric field poling method in stoichiometric LiTaO(3), and their conversion efficiencies, as well as angular and thermal dependencies, were characterized by second harmonic generation.
authors.forename: Dror
authors.initials: D
authors.lastname: Kasimov
authors.forename: Ady
authors.initials: A
authors.lastname: Arie
authors.forename: Emil
authors.initials: E
authors.lastname: Winebrand
authors.forename: Gil
authors.initials: G
authors.lastname: Rosenman
authors.forename: Ariel
authors.initials: A
authors.lastname: Bruner
authors.forename: Pnina
authors.initials: P
authors.lastname: Shaier
authors.forename: David
authors.initials: D
authors.lastname: Eger