Tunable Metasurfaces Based on Mechanically Deformable Polymeric Substrates

The emergence of metamaterials has presented an unprecedented platform to control the fundamental properties of light at the nanoscale. Conventional metamaterials, however, possess passive properties that cannot be modulated post-fabrication, limiting their application spectrum. Recent metasurface research has explored a plethora of active control mechanisms to modulate the optical properties of metasurfaces post-fabrication. A key active control mechanism of optical properties involves the use of mechanical deformation, aided by deformable polymeric substrates. The use of deformable polymeric substrates enables dynamic tuning of the optical properties of metasurfaces including metalenses, metaholograms, resonance, and structural colors, which are collectively relevant for biosensing and bioimaging. Deformable–stretchable metasurfaces further enable conformable and flexible optics for wearable applications. To extend deformable–stretchable metasurfaces to biocompatible metasurfaces, a fundamental and comprehensive primer is required. This review covers the underlying principles that govern the highlighted representative metasurface applications, encompassing stretchable metalenses, stretchable metaholograms, tunable structural colors, and tunable plasmonic resonances, while highlighting potential advancements for sensing, imaging, and wearable biomedical applications.