Soft plasmonics: design, fabrication, characterization, and applications

Plasmonic nanostructures are important building blocks in modern nanoscience and nanotechnology. Significant research efforts have been directed toward developing solution-based or rigid-substrate-supported metallic nanostructures for novel applications in biophotonics, sensing, energy, and medicine. In parallel, there has been an increasing interest in the fabrication of plasmonic nanostructures on elastomeric substrates and exploring the impact of mechanical deformation including bending, torsion, and stretching on the collective plasmonic resonance properties. This burgeoning field may be defined as soft plasmonics (or soft mechanoplasmonics), analogous to soft electronics. This review describes the recent progress in the design, fabrication, characterization, properties, and applications of soft plasmonics. Soft plasmonics are expected to afford complementary features and functions to the field of soft electronics, enabling applications that are difficult or impossible to achieve with traditional rigid plasmonic structures, such as conformal attachment or integration with soft biological systems for real-time sensing, actuation, and close-loop feedback.