Modulational instability and solitons in nonlocal media with competing nonlinearities

High-order optical nonlinearities in plasmonic nanocomposites—a review

“…Spatial modulation instability (SMI) is a phenomenon that appears due to competition between nonlinearity and diffraction effects being enhanced by the exponential growth of the optical field amplitude and phase noise [110]. The SMI may be strongly affected by high-order dispersive effects [138,139], saturation of the nonlinearity [140], nonlocal nonlinearity [141,142], and coherence properties of optical beams [143,144]. The instability growth produces changes in the transverse beam profile, along the light beam propagation, which may lead to a filamentation regime [145].…”

“…A particular example is the stable propagation of spatial solitons, which will be discussed in Subsection 6.3. One relation between SMI and spatial solitons is manifested in the fact that the filaments that emerge from the SMI process have the behavior of solitary waves that under certain conditions may travel without suffering deformation [142].…”

The interaction of dark solitons with competing nonlocal cubic nonlinearities

“…4b. This phenomenon is most likely caused by the inadequacy of our ansatz of the soliton in the highly nonlocal regime [39,42,68]. From Fig.…”

“…The positive and negative signs of the index α 2 represent the competing self-focusing and self-defocusing nonlinearities, respectively. It has also been shown that the stationary dark soliton solution always exists if α 1 + α 2 < 0 [68,72].…”

Highly nonlocal optical response: Benefit or drawback?

“…In fact, the latter tend to exhibit singularities in the origin, which lead to relevant differences when applying the Snyder-Mitchell model 145 . The Gaussian kernel (3.3) was used to study the role of nonlocality in modulational instability and the resulting formation of solitary waves 139,140,141 in a general Kerr-like nonlocal medium as, in general, nonlocality acts to quench modulational instability 146 .…”