Nonlinear optical scattering: The concept of effective susceptibility

Abstract

We present a general theoretical method for deriving effective susceptibilities for (non)linear optical scattering processes of arbitrary order using the reciprocity principle. This method allows us to formulate a generalized treatment of nonlinear optical scattering and deduce selection rules independent of the precise mechanism of light-matter interaction. We particularize this approach to second-order sum frequency scattering from an inhomogeneous medium and consider the limiting cases of small particle scattering, refractive index matched (Rayleigh-Gans-Debye) scattering, small refractive index contrast (Wentzel-Kramers-Brillouin) scattering and correlated scattering. We compare the derived expressions to experimental results of sum frequency scattering from monodisperse particles in suspension with varying sizes.

Strong Modification of the Nonlinear Optical Response of Metallic Subwavelength Hole Arrays

“…It may seem surprising that an SHG signal is obtained from this centrosymmetric structure using excitation and detection angles that are perpendicular to the sample [8,19]. We remark, however, that symmetry breaking at an interface can be sufficient to generate a scattered beam of second-harmonics (SH) light [20], which can be detected if the collection NA is large enough to include such scattering angles [4].…”

Communication: Reactions and adsorption at the surface of silver nanoparticles probed by second harmonic generation

“…On the other hand, though the particle is small, its finite size still enables the phase matching condition for SHG at the particle surface to be satisfied at large scattering angles. [6][7][8][9] Indeed, SHG from molecules with large hyperpolarizability adsorbed on dielectric nanoparticle surfaces has been detected at large scattering angles. [10][11][12][13] In the case of metallic nanoparticles, the surface layer should have a large enough hyperpolarizability to allow for direct detection of surface generated SH signal even in the absence of an adsorbed layer of hyperpolarizable molecules.…”

A simple model for dynamic small-angle X-ray diffraction in colloidal crystals

“…Under these circumstances, the diffraction of a plane electromagnetic wave on a sample can be modeled by the Wentzel-Kramers-Brillouin (WKB) approximation. This model, which found prior application in quantum mechanics (Sakurai, 1994), visible optics (Deirmendjian, 1957) and nonlinear optics (Roke et al, 2004), treats the experimental sample as a pure phase object. Thus, when irradiated with a plane wave, the wave emerging from the sample is assumed to still be completely parallel, but modulated by a phase factor proportional to the pass lengths of the wave through different compounds (with different, non-complex, indices of refraction).…”