Plasmonic Thermal Emitters for Dynamically Tunable Infrared Radiation

Periodic bimetallic microstructures using nickel and gold are fabricated on an elastomeric substrate by use of strain‐induced buckling of the metallic layers, which can be compatible with roll‐to‐roll manufacturing. The intrinsically low emissivity of gold in the midinfrared regime is selectively enhanced by the surface plasmonic resonance at three different midinfrared wavelengths, 4.5, 6.3, and 9.4 µm, respectively, which directly correspond to the structural periodicities of the metallic microstructures. As the thermal emission enhancement effect exists only for the polarization perpendicular to the orientation of the microstructures, substantially polarized thermal emission with an extinction ratio close to 3 is demonstrated. Moreover, the elastically deformed plasmonic thermal emitters demonstrate strain‐dependent emission peaks, which can be applied for future mechano–thermal sensing and dynamic thermal signature modulation.