Direct observation of controlled strain-induced second harmonic generation in a Co0.25Pd0.75 thin film on a Pb(ZrTi)O3 substrate

Abstract

The authors have observed strain-induced second harmonic generation ͑SHG͒ signals from a Co 0.25 Pd 0.75 alloy film deposited on a lead zirconate titanate ͑PZT͒ substrate. The strain in the sample was controlled by the inverse piezoelectric effect. The authors demonstrate that it is possible to separate the strain contribution to the SHG signal from the crystallographic contribution and that from the electric polarization in PZT. An estimate of the value of the nonlinear photoelastic tensor components is in very good agreement with previous calculations.

Resonance-type thickness dependence of optical second-harmonic generation in thin films of the topological insulatorBi2Se3

“…Furthermore, the change of the lattice constants that we measured using x-ray diffraction can be estimated to be as small as <0.5% over the entire range of film thicknesses used. Additionally, the straininduced enhancement of the SHG intensity usually shows a smooth dependence with increasing strain [50,51], i.e., it disagrees with our resonance-type observation. In contrast, the observed about twofold increase of the absorption coefficient of Bi 2 Se 3 films with decreasing film thickness from 40 to 6 nm has been evidenced to be due to the free carrier (Drude) absorption with increasing free carrier density [34,36].…”

“…It should be noted that other sources of the resonant enhancement of SHG from Bi 2 Se 3 films seem to be less probable. Specifically, the strain-induced SHG enhancement, which usually manifests itself in thin films, 50,51 is expected to be weak for several reasons. First, the effect of the strain on the optical properties with decreasing Bi 2 Se 3 film thickness deduced from Raman spectroscopy is ~1%.…”

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.…”

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.…”