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

Abstract

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)(5)O(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)(5)O(12) 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's constitutive elements and finds the nonlinear response to increase with yttrium concentration.

Resonantly Enhanced Second-Harmonic Generation Using III–V Semiconductor All-Dielectric Metasurfaces

“…Nonetheless, we show that the surface mediated SHG can exhibit very different behavior than the SHG due to a bulk nonlinearity. Moreover, as has been demonstrated in other materials [41][42][43][44] , lattice mismatch between the GaAs and AlGaO underlayer induces strain in the GaAs close to the AlGaO interface which may also change the surface nonlinearity. Finally, figure 4(i) shows the SH spectra obtained as the location of the focused pump beam is varied across the metasurface.…”

Probing structural inhomogeneity of graphene layers via nonlinear optical scattering

“…At the same time, as was mentioned in the introduction, external influence such as mechanical stress can break this symmetry and lead to the dipole SHG. Such mechanism of the inversion symmetry breaking was already reported to be responsible for the strain-induced SHG in silicon [30] and SHG induced by the intrinsic mechanical strain in iron garnet films [31]. Other mechanisms that may lead to the enhanced SHG at the wrinkles are local field enhancement due to the curvature, variations of thickness at the boundaries reported for CVD graphene [15], or charge puddles [32] induced by local curvature of the film, and giving birth to the electric-field induced SHG [33].…”

Nonlinear optical diffraction by standing acoustic waves in a GaAs film

“…Later, strain-induced three-photon effects such as optical SHG in strained crystals and hyper-Rayleigh light scattering by dislocation deformation were theoretically investigated [20], as well as SHG due to misfit strain and misfit dislocations at filmsubstrate interfaces [21]. Similarly, experimental observations of strain-induced SHG were reported in silicon wafers [22] and the influence of strain on SHG in Co 0.25 Pd 0.75 films on a PZT substrate [23], in bismuth-substituted iron garnet films [24], as well as in bulk silicon [25,26] were discussed.…”