info:eu-repo/semantics/article
Light generation at the anomalous dispersion high energy range of a nonlinear opal film
Fecha
2009-12Registro en:
Botey, Muriel; Maymó, Marc; Molinos-Gómez, Alberto; Dorado, Luis Antonio; Depine, Ricardo Angel; et al.; Light generation at the anomalous dispersion high energy range of a nonlinear opal film; Optical Society of America; Optics Express; 17; 15; 12-2009; 12210-12216
1094-4087
CONICET Digital
CONICET
Autor
Botey, Muriel
Maymó, Marc
Molinos-Gómez, Alberto
Dorado, Luis Antonio
Depine, Ricardo Angel
Lozano, Gabriel
Mihi, Agustín
Míguez, Hernán
Martorell, Jordi
Resumen
We study experimentally and theoretically light propagation and generation at the high energy range of a close-packed fcc photonic crystal of polystyrene spheres coated with a nonlinear material. We observe an enhancement of the second harmonic generation of light that may be explained on the basis of amplification effects arising from propagation at anomalous group velocities. Theoretical calculations are performed to support this assumption. The vector KKR method we use allows us to determine, from the linear response of the crystal, the behavior of the group velocity in our finite photonic structures when losses introduced by absorption or scattering by defects are taken into account assuming a nonzero imaginary part for the dielectric constant. In such structures, we predict large variations of the group velocity for wavelengths on the order or smaller than the lattice constant of the structure, where an anomalous group velocity behavior is associated with the flat bands of the photonic band structure. We find that a direct relation may be established between the group velocity reduction and the enhancement of a light generation processes such as the second harmonic generation we consider. However, frequencies for which the enhancement is found, in the finite photonic crystals we use, do not necessarily coincide with the frequencies of flat high energy bands. © 2009 Optical Society of America.