Second-harmonic generation for a dilute suspension of coated particles

Abstract

We derive an expression for the effective second-harmonic coefficient of a dilute suspension of coated spherical particles. It is assumed that the coating material, but not the core or the host, has a nonlinear susceptibility for second-harmonic generation (SHG). The resulting compact expression shows the various factors affecting the effective SHG coefficient. The effective SHG per unit volume of nonlinear coating material is found to be greatly enhanced at certain frequencies, corresponding to the surface plasmon resonance of the coated particles. Similar expression is also derived for a dilute suspension of coated discs. For coating materials with third-harmonic (THG) coefficient, results for the effective THG coefficients are given for the cases of coated particles and coated discs.

Light scattering from anisotropic particles: propagation, localization, and nonlinearity

“…It is interesting to note that when the anisotropy ratio decreases, the surface plasmon resonances 3 sp exhibit blue shifts, accompanied with large enhancement of the SHG susceptibility. It can also be found that the nonlinearity enhancement in the nondilute limit is larger than the one in the dilute limit [32,95].…”

“…For instance, enhanced optical third-order nonlinearity in core-shell structures was discuused in [94], and nonlinear susceptibilities for SHG and THG through core-shell nanostructures were discussed in [95,96]. However, those constituents are basically isotropic.…”

Theory of enhanced second-harmonic generation in some artificial materials

“…For such a material, there is not only an incident light, but also an external magnetic field H. The latter yields the formation of chains of coated nanoparticles [16], changing the microstructure of the system and thus yielding the effective SHG with magnetic-field controllabilities. This kind of SHG is expected to receive broad interest in the physics, optics, and engineering communities, because it is difficult or impossible to achieve with conventional, naturally occurring materials or random composites [1,2,4,5,17,18].…”

Second and third harmonic generations in random composites of spheroidal particles

“…Later, general expressions for effective susceptibilities for SHG and third harmonic generation (THG) of composite media were developed by Hui et al in terms of the second-order and third-order optical susceptibilities of the components [7,8]. More recently, second and third harmonic generations for a dilute suspension of coated particles [9] and a dilute component with graded nonlinear particles [10] have been investigated.…”