Observation of nonlinearity-controlled switching of topological edge states

Abstract

We report the experimental observation of the periodic switching of topological edge states between two dimerized fs-laser written waveguide arrays. Switching occurs due to the overlap of the modal fields of the edge states from topological forbidden gap, when they are simultaneously present in two arrays brought into close proximity. We found that the phenomenon occurs for both strongly and weakly localized edge states and that switching rate increases with decreasing spacing between the topological arrays. When topological arrays are brought in contact with nontopological ones, switching in topological gap does not occur, while one observes either the formation of nearly stationary topological interface mode or strongly asymmetric diffraction into the nontopological array depending on the position of the initial excitation. Switching between topological arrays can be controlled and even completely arrested by increasing the peak power of the input signal, as we observed with different array spacings.

Topological Photonic States in Waveguide Arrays

“…With increasing input power, the nonlinear term becomes vital for the dynamic of light in topological waveguide arrays and may trigger some novel phenomena, such as nonlinear topological solitons, [118][119][120] nonlinearity-induced topological phase transitions, [121] and nonlinearity-controlled switching. [122] The experimental research on nonlinearity in the waveguide array mainly focused on two systems. One is the anomalous Floquet TIs.…”

Macroscopic Zeno Effect in a Su–Schrieffer–Heeger Photonic Topological Insulator

“…In optics, various switching and coupling mechanisms have been explored, such as Floquet insulators realized with helical waveguide arrays [ 8 ] and Su–Schrieffer–Heeger (SSH) chains. [ 9–11 ] The resonant switching of topologically protected edge states and valley Hall edge states have been theoretically studied in refs. [12, 13].…”

Light gap bullets in defocusing media with optical lattices

“…Introduction.-It is a challenging issue to create stable three-dimensional (3D) localized modes (alias solitons) owning to the inherent supercritical wave collapse triggered by attractive cubic (Kerr) nonlinearity (critical wave collapse also exists in two-dimensional (2D) settings) [1][2][3][4][5][6][7][8][9]. To against such high-dimensional wave collapses in the soliton research field in diverse branches of science, it is therefore necessary to introduce extra physical effects, including synthetic periodic potentials [10][11][12][13][14][15][16][17][18][19][20], saturable absorber [21,22], optical cavity [23][24][25], semiconductor active [26] or quadratic nonlinear media [27], waveguide and fiber arrays [28][29][30][31], materials with nonlocal [32,33] or competing (focusing) cubic and (defocusing) quintic nonlinearities [34,35], linear spin-orbit coupling [36], etc.…”

“…Corresponds what with this is the 3D spatiotemporal solitons supported by 2D complex lattices were reported so far merely in the self-focusing (attractive, g < 0) nonlinearity regime. In particular, the periodic potentials have shown incomparable band-gap control engineering within where new localized states called localized gap modes like gap solitons and vortices were and still are warmly explored in both experimental and theoretical sides [10][11][12][13][14][15][16][17][18][19][20]. It is therefore a pronounced imagine is to reveal the formation of 3D spatiotemporal solitons in finite gaps of the 2D optical lattices and how and what their stabilization and dynamics configurations would look like.…”