Strain-Modulated Reconfigurable Optical Information Processing in Flexible Graphene/PDMS

All-optical information processing, featuring ultrafast response and immunity to electromagnetic interference, plays a pivotal role in future communications and computing technologies. Graphene, with its exceptional nonlinear optical properties and mechanical flexibility, emerges as an ideal candidate for flexible photonic devices. However, graphene-based photonic components are typically functionally fixed and lack dynamic reconfigurability. Here, we integrate graphene with polydimethylsiloxane (PDMS) to fabricate a flexible graphene/PDMS composite and investigate its spatial self-phase modulation (SSPM) effect under mechanical strain. Our results demonstrate that the nonlinear optical response of the composite can be dynamically tuned by strain. Under 532 nm laser excitation (intensity 35 W/cm²), increasing the tensile strain from 0% to 40% continuously suppresses the number of SSPM diffraction rings from 8 to 0, while accompanied by a reduction in the third-order nonlinear susceptibility ${\chi }_{\mathrm{monolayer}}^{\left(3\right)}$ from 1.357 × 10^-7 to 6.125 × 10^-8 e.s.u. This tunable SSPM effect originates from strain-induced modifications in both the effective number of optically interacting layers and the electronic band structure of graphene. Leveraging this mechanism, we further designed a strain-gated optical switch and reconfigurable optical logic gates, enabling flexible switching between "OR" and "AND" gates. This work opens new avenues for graphene-based tunable nonlinear photonic devices.