title: Equifrequency surfaces in a two-dimensional GaN-based photonic crystal.
abstract: We established the angular conditions that maintain the quasi-phase matching conditions for enhanced second-harmonic generation. To do that, we investigated the equifrequency surfaces of the resonant Bloch modes of a two-dimensional periodic, hole-array photonic crystal etched into a GaN/sapphire epitaxial structure. The equifrequency surfaces exhibit remarkable shapes, in contrast to the simpler surfaces of a one-dimensional structure. The observed anisotropy agrees well with the surfaces calculated by a scattering matrix method. The equifrequency surfaces at fundamental and second-harmonic frequencies provide the values of polar and azimuthal angles that maintain quasi-phase matching conditions for enhanced second-harmonic generation over an extended tuning range. The predicted values for quasi phase-matching conditions show that frequency tuning for the two-dimensional case covers an about two times larger fractional bandwidth relative to the one-dimensional case.
authors.forename: D
authors.initials: D
authors.lastname: Coquillat
authors.forename: J
authors.initials: J
authors.lastname: Torres
authors.forename: D
authors.initials: D
authors.lastname: Peyrade
authors.forename: R
authors.initials: R
authors.lastname: Legros
authors.forename: J
authors.initials: J
authors.lastname: Lascaray
authors.forename: M
authors.initials: M
authors.lastname: Le Vassor d'Yerville
authors.forename: E
authors.initials: E
authors.lastname: Centeno
authors.forename: D
authors.initials: D
authors.lastname: Cassagne
authors.forename: J
authors.initials: J
authors.lastname: Albert
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: De La Rue