Influence of spatial delay on the modulational instability in a composite system with a controllable nonlinearity

Abstract

A theoretical investigation of the modulational instability (MI) in a composite system with a nonlocal response function is presented. A composite system of silver nanoparticles in acetone is chosen, whose nonlinearity can be delicately varied by controlling the volume fraction of the constituents, thus enabling the possibility of nonlinearity management. A pump-probe counterpropagation configuration has been assumed, and the interplay between the competing nonlinearities and the nonlocalities in the MI dynamics is systematically explored. A different class of nonlocalities have been considered, and the study reveals that the nonlocality critically depends on the kind of nonlocal function. However, the general behavior is that the strength of nonlocality suppresses the MI gain, while for a rectangular function it assists the emergence of new spectral windows. We also show that the cross coupling effects are significant in enhancing MI, especially in the defocusing nonlinearity. We also emphasize the impact of the relative strength of the nonlinearities in the MI dynamics at different settings of competing nonlinearities. Thus, we emphasize the importance of the different class of nonlocal response in the MI dynamics and explore the interplay between the higher order nonlinear effects and nonlocalities in the counterpropagating configurations.

Controlling light with light in silver-nanospheres and gold-nanorods colloids

“…Indeed, metal colloids are excellent systems for exploitation of concepts directly related to multidimensionality. Of course there are plenty of possible developments in this area as already pointed out by many authors (see for example: Walasik et al, 2017;Reyna and de Araújo, 2017;Kumar et al, 2018;Trofimov and Lysak, 2018;Kassab and de Araújo, 2019;Ortega et al, 2019, Kartashov et al, 2019, Malomed, 2019. Moreover, with new theoretical advances and the development of nanofabrication techniques exciting challenges and applications are expected for the near future.…”

Nonlocal cubic and quintic nonlinear wave patterns in pure-quartic media

“…According to Esbensen et al [28], the coexistence of dark and bright spatial solitons in the same medium may be achieved by varying the beam's intensity under a well-controlled balance between focusing and defocusing cubic nonlinearities. Moreover, the crossphase modulation induced spatial MI in a composite medium with a nonlocal nonlinear response was studied [29]. In recent years, localized spatiotemporal solitons were studied in a nonautonomous nonlocal NLS equation [30].…”