Ferroelectric crystals are important materials in many kinds of applications. Since the invention of so called quasi-phase matching technique, periodically domain-inverted ferroelectrics crystals with modulated second order nonlinear susceptibility are widely used in frequency conversion application. In periodically domain-inverted ferroelectrics crystals, besides the nonlinear optical coeffici...

Quadratic electro-optic effects (QEOEs) and electro-absorption (EA) process in a GaN/AlGaN spherical quantum dot are theoretically investigated. It is found that the magnitude and resonant position of third-order nonlinear optical susceptibility depend on the nanostructure size and aluminum mole fraction. With increase of the well width and barrier potential, quadratic electro-optic effect and ...

We investigate theoretically the effective second-harmonic generation (SHG) susceptibility in graded films of metal–dielectric random composites with anisotropically shaped particles by invoking the local field effects. Using numerical examples, we demonstrate that in the presence of gradation profiles and/or shape effects, graded metal–dielectric films could be used as novel optical materials ...

Beamswhich follow curved trajectories are useful in a variety of applications, but up to now have been realized mainly in linear media. We demonstrate theoretically and experimentally the generation of second-harmonic (SH) beams which follow arbitrary convex caustic trajectories. These beams are created in a nonlinear photonic crystal with a second-order susceptibility having a tailored pattern...

The nonlinear oscillator model allows a basic understanding of all nonlinear processes and can be adopted to analyse optical vibrational modes and electronic transitions in molecules and crystals, in order to derive general properties of harmonic generation to all orders. In particular, we obtain Kramers-Krönig relations and sum rules referred to all momenta of the susceptibility, and Miller’s ...

The development of modulation instability for two beams copropagating in a medium with noninstantaneous nonlinear response is investigated. The frequency dependence of the experimentally observed spectral broadening reveals the presence of two-beam coupling, resulting from the time-delayed Raman part of the third-order nonlinear susceptibility. We present an analysis of the experimental data, w...

When a high-power optical signal is launched into a fiber, the linearity of the optical response is lost. One such nonlinear effect, which is due to the third-order electric susceptibility is called the optical Kerr effect. 1), 2) Four-wave mixing (FWM) is a type of optical Kerr effect, and occurs when light of two or more different wavelengths is launched into a fiber. Generally speaking FWM o...

Based on one-dimensional single-electron infinite periodic models of transpolyacetylene, we show analytically that the overall permutation symmetry of nonlinear optical susceptibilities is, although preserved in bound-state molecular systems, no longer generally held in periodic systems. The overall permutation symmetry breakdown provides a natural explanation of the widely observed large devia...

Au:BaTiO(3) composite films comprising hexagon-shaped Au nanoparticle arrays covered with BaTiO(3) matrix were fabricated by double-layer nanosphere lithography and pulsed laser deposition technique. The optical nonlinearity of the composite film was determined using the Z-scan technique at a wavelength of 532 nm and a pulse duration of 25 ps. The third-order nonlinear optical susceptibility, c...

An analytical expression for the low-temperature optical susceptibility of quantum-well semiconductor lasers is presented based on a simple parabolic band model. The optical susceptibility obtained keeps the nonlinear dependence on the carrier density, providing both a broad gain spectrum and a dispersion curve, so it can be used to analyze the dynamics of multimode devices or devices with larg...