Second harmonic generation study of internally-generated strain in bismuth-substituted iron garnet films

The present article highlights the lattice-imperfection and compositional origins of the nonlinear optical response in bismuth-substituted iron garnet films. In particular the roles of lattice mismatch strain and micro-strain on second harmonic generation in (Bi,Y)3(Fe,Ga)5O 12 films are elucidated based on experimental findings. It is found that lattice mismatch strain drives the second harmonic signal in (Bi,Y) 3(Fe,Ga)5O12 films, in agreement with theoretical predictions; however micro-strain was found not to correlate significantly with the second harmonic signal at the micro-strain levels present in these samples. The present study also elaborates on the influence of the film\u27s constitutive elements and finds the nonlinear response to increase with yttrium concentration. © 2010 Optical Society of America

Nonlinear Verdet law in magnetophotonic crystals : interrelation between Faraday and Borrmann effects

The magneto-optical Faraday effect is studied in one-dimensional magnetophotonic crystals (MPCs). Mechanisms of a strong enhancement of the Faraday rotation at the edges of the photonic band gap are considered. High difference of refractive indexes of bismuth-substituted yttrium iron garnet (Bi:YIG) and SiO₂ layers provides a strong spatial localization of the optical field in Bi:YIG layers, which leads to manifold Faraday rotation enhancement at the photonic band edges. The Faraday rotation angle in the finite MPCs appears to be a nonlinear function of the total thickness of magnetic material in the stack that can be interpreted as the nonlinear Verdet law. Relation between the enhancement of the Faraday rotation and localization of optical field in magnetic layers is treated as a Borrmann-type effect. This relation shows that the Faraday rotation can be considered as a measure of the density of photonic states trapped within Bi:YIG layers.4 page(s