Spectral evolution of an optical pattern generated by spatial modulation instability in a reorientational Kerr nonlinear medium

Abstract

An experimental investigation is reported on the role of molecular reorientational nonlinearity in the spectral evolution of multifilamentation patterns induced by spatial modulation instability (MI) in a nonlinear Kerr medium. The influence of molecular reorientational Kerr nonlinear response on the spatial MI is analyzed theoretically by the standard stability analysis. The spatial MI gain spectra obtained by experimental measurements were found to agree with the theoretical derivation. In addition, by changing the launch average power, we also analyze the spatial spectral behavior of the optical pattern in such media. It is shown that, for higher launch average power, there will be secondary spatial stripes, manifesting as the original spatial modulation frequency doubling in the spatial frequency domain, which originated from the molecular reorientational Kerr nonlinearity response.

Nonlinear optical properties of Au-nanoparticles conjugated with lipoic acid in water

“…Some potential applications go from biological to electronic applications, some of them are: sensor technology [3]- [5], biological labeling, drug delivery system and treatment for some cancers [6,7], surface-enhanced Raman scattering, paintings [8], optical diodes, high speed optical logic devices [9]; on the other hand, properties of nanoparticles as the thermal conductivity and nonlinear optical properties, are interesting, because by using nanoparticles it is possible to elevate the thermal conductivity of fluids being these metallic [10]- [12], or nonmetallic [13,14] with different shapes and sizes, and suspended in different fluids, which modified the nonlinear optical properties of fluids. Nonlinear optical gives origin to nonlinear optical phenomena as modulation instability [15,16], self-diffraction [17,18], nonlinear shock waves [19,20], stabilization of complex soliton structures [21,22], and these phenomena can be applied to design optical limiters, multiplexors, modulators, ultrafast optical communication [23]- [25]. In particular, the behavior of Au-nanoparticles in different media has been reported by using the z-scan technique [25]- [27].…”