Quadratic Nonlinear Materials Research Articles

Active reflection via a phase-insensitive quadratic nonlinear interaction within a microcavity

The reflectivity of a microcavity filled with a quadratic nonlinear material is shown to be actively changed by the interaction of two waves. Within this microcavity, the reflection coefficient of a weak wave at the fundamental frequency is changed from almost 0% to a value in the vicinity of 100% by the simultaneous incidence of an intense wave at the second-harmonic frequency. This change in reflectivity is shown to be in a large degree insensitive to the input phase difference between the two waves.

Observation of azimuthal modulation instability and formation of patterns of optical solitons in a quadratic crystal:?errata

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text Dmitri V. Petrov, Lluis Torner, Jordi Martorell, Ramon Vilaseca, Juan P. Torres, and Crina Cojocaru, "Observation of azimuthal modulation instability and formation of patterns of optical solitons in a quadratic crystal:?errata," Opt. Lett. 23, 1787-1787 (1998) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Observation of azimuthal modulational instability and formation of patterns of optical solitons in a quadratic nonlinear crystal

We report what is believed to be the first experimental demonstration of the azimuthal self-breaking of intense beams containing a vortex phase dislocation into sets of optical spatial solitons in a quadratic nonlinear material. The observations were performed in a KTP crystal.

Spatial control of beams in quadratic non-linear materials

A numerical study of the propagation of intense beams in a quadratic non-linear material is presented, when a second-harmonic amplification process occurs. Sinusoidal spatial amplitude modulation of the input fields is shown to be able to control the splitting of the propagating beams and their stability. We demonstrate that a spatial control of the fields can be performed under appropriate conditions on the amplitude of the interacting fields.

Pseudo-metal reflection at the interface between a linear and a nonlinear material

We study theoretically the reflectivity variation of a light wave at the interface between a linear material and a quadratic nonlinear material, upon simultaneous incidence of a wave at the second harmonic frequency overlapped with the first one. The presence of the phase-coherent second harmonic wave results in a phase dependent modification of the effective complex linear susceptibility of the nonlinear medium. Depending on the phase difference between these beams different phenomena occur. Pseudo-metal reflection occurs when there is a net transfer of photons from one wave to the other, whereas modified Fresnel reflection takes place when there is no net transfer of photons.

Solitary waves in Bragg gratings with a quadratic nonlinearity

We study the formation of solitary waves in quadratic nonlinear materials where the dispersion is provided by linear mode coupling mediated by a Bragg grating. We show that solitary wave solutions can be analytically found provided that the coupling of the second-harmonic waves considerably exceeds that of the fundamental ones. Furthermore, we numerically determine solitary wave solutions for the general case. These solutions prove to be close to the analytical ones. A nontrivial property of Bragg grating solitary waves is that they do not fill the complete parameter space where exponentially decaying functions are allowed to exist. Instead, we find internal boundaries inside this parameter space where the soliton intensity diverges. Moreover, double-hump solutions are found where a numerical propagation procedure shows that some of them are fairly robust.

Asymptotic wave-wave processes beyond cascading in quadratic nonlinear optical materials.

The method of multiple scales is used to derive several different systems of evolution equations for multiple interacting waves propagating in a strongly dispersive, weakly quadratically nonlinear optical material. Several two- and three-wave signaling problems are discussed. Among the problems discussed are the interaction between a low frequency field and the optical frequency field and between the optical frequency field and its second-harmonic field. In the efficient phase-matching regime, three-wave-mixing equations are obtained where quadratic nonlinearities dominate. Here, methods are discussed for cascading second-order nonlinearities to obtain intensity-dependent effects. For the large-phase-mismatch regime, cross-phase-modulation equations, analogous to fiber optics, are obtained where cubic nonlinearities dominate, and intensity-dependent modulations beyond cascading are obtained. Finally, the three-interacting (sum frequency) wave problem is examined for small and large asymptotic phase mismatch regimes. Analytical solutions to the derived evolution equations are given.