Shape-Memory Photonic–Plasmonic Crystals for Programmable Surface-Enhanced Raman Scattering

Abstract

Surface-enhanced Raman scattering (SERS) has emerged as a powerful analytical technique for ultrasensitive molecular detection. Integrating photonic architectures with plasmonic nanostructures provides an effective strategy to enhance SERS by exploiting slow-photon effects. However, continuously and reversibly controlling photonic enhancement remains a significant challenge. Here, we report a shape-memory photonic–plasmonic crystal (SMPPC) that enables programmable slow-photon signal enhancement through reversible structural reconstruction. By exploiting its shape-memory properties, the optical response of SMPPC can be reversibly modulated through solution evaporation or mechanical contact. Structural reconstruction dynamically modulates the spectral detuning between the excitation wavelength and the photonic stopband edge, resulting in a nonmonotonic SERS response governed by the interplay between plasmonic hotspot evolution and slow-photon effect. The fully recovered SMPPC substrate delivers an 8.1-fold enhancement in SERS intensity compared with the plasmonic copolymer SERS substrate. As a proof of concept, the SMPPC substrate enables the detection of antibiotics in municipal wastewater effluents at concentrations down to 471 ppt. This work establishes shape-memory-enabled photonic reconfiguration as a strategy for programmable manipulation of SERS, opening new opportunities for adaptive photonic–plasmonic sensing platforms.