Generation and reconfiguration of dual-band infrared plasmonic slit resonances from nano-kirigami structures

Dynamic modulation of infrared optical properties has significant importance for thermal imaging, molecular sensing, and communications. However, conventional dynamic metasurfaces, which rely on integrating functional materials such as phase-change materials or liquid crystals, face challenges such as complex fabrication, limited modulation range, and slow response speed. Here, the dynamic tuning of dual-band infrared resonances is demonstrated by reversibly deforming plasmonic slits in electrically reconfigurable nano-kirigami structures. The structural design adopts an Au-SiO₂-Si layered configuration, enabling reversible transformation from 2D planar patterns to 3D morphologies via electrostatic actuation. The pre-designed 2D patterns support dual-band plasmonic slit resonances, whose resonance wavelengths and intensities can be precisely controlled by geometric parameters. Under applied voltage, the structure undergoes controllable out-of-plane deformation, which breaks the in-plane symmetry of the plasmonic slits and modifies their effective length, width, and height. This enables dynamic, continuous, and reversible tuning of both the resonance intensity and wavelength. Simulations and experimental results confirm the prominent dual-band resonance responses, as well as the significant reconfiguration. Our work offers a new strategy for high-performance, easily integrable, and dynamically tunable infrared photonic devices, with potential applications in infrared sensing, spectral modulation, and adaptive optical systems.