10/29/2022 0 Comments Sumaru spirobenzopyran![]() ![]() Importantly, they form the basis of the next-generation light-guiding-light approach to optical signal processing, which envisions a circuitry-free, reconfigurable, and multilayered photonics technology powered by the dynamic interactions of self-trapped beams ( 13, 14). Because they travel without changing shape, self-trapped beams hold potential for optical interconnects ( 11), applications in image transmission ( 12), rerouting light ( 13, 14), and logic gates for computing ( 15). These nonlinear waves propagate without diverging through self-inscribed waveguides and exhibit intriguingly particlelike interactions such as collisions ( 5), fusion and birth ( 6), annihilation ( 7), and spiraling ( 8), typically in the short range (where there is significant overlap in their optical fields) and in rare cases, over long distances (where overlap is negligible and beams are remote) ( 9, 10). Self-trapped light beams and spatial solitons emerge in a rich variety of photoresponsive materials that display intensity-dependent changes in refractive index ( 1 – 4). Furthermore, this opto-chemo-mechanical transduction of energy mediated by the 3D cross-linked hydrogel network facilitates pairwise interactions between self-trapped beams both in the short range where there is significant overlap of their optical fields, and even in the long range––over separation distances of up to 10 times the beam width––where such overlap is negligible. The waveguide is erased and reformed within seconds when the optical field is sequentially removed and reintroduced, allowing the self-trapped beam to be rapidly and repeatedly switched on and off at remarkably low powers in the milliwatt regime. A Gaussian beam self-traps when localized isomerization-induced contraction of the hydrogel and expulsion of water generates a transient waveguide, which entraps the optical field and suppresses divergence. Through comprehensive experiments and simulations, we show that the unique nonlinear conditions arise when photoisomerization of spiropyran substituents in pH-responsive poly(acrylamide- co-acrylic acid) hydrogel transduces optical energy into mechanical deformation of the 3D cross-linked hydrogel matrix. We find that repeatedly switchable self-trapped visible laser beams, which exhibit strong pairwise interactions, can be generated in a photoresponsive hydrogel. Progress, however, has been limited by the need for reversibly responsive materials that host such nonlinear optical waves. Furthermore, it was confirmed that the highly cross-linked cylindrical gel rod with macroporous structure showed rapid bending deformation due to the asymmetric light irradiation.Next-generation photonics envisions circuitry-free, rapidly reconfigurable systems powered by solitonic beams of self-trapped light and their particlelike interactions. ![]() It was found that the fastest photo- and thermo-responsive shrinking was observed for loosely crosslinked porous hydrogels. The time dependence of bending deformation due to the asymmetric light irradiation as well as kinetics of shrinking has been measured. ![]() Both photo- and thermo-responsive properties of gels have been investigated and compared. Poly( N-isopropylacrylamide) gels were functionalized with photo-responsive spirobenzopyran and solvent/nonsolvent mixtures were used as swelling agent to introduce network heterogeneities during the gelation process. Since any technical application of polymer gels critically depends on the response rate, therefore porous hydrogels have been prepared in order to accelerate the response reaction. Novel hydrogels that shrink in response to light irradiation and temperature change have been developed. ![]()
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