Bicolor Regulation of an Ultrathin Absorber in the Mid-Wave Infrared and Long-Wave Infrared Regimes

Thermal radiation in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) regions profoundly influences human lives. However, most thermal radiation regulators exhibit mismatched spectral characteristics and multiband incompatibility. Here, we introduce a new type of ultrathin absorber & horbar;a dual-band dynamic optical coating (DBDOC)& horbar;to realize the independent regulation of MWIR and LWIR regions. A new framework of thermal radiation regulation is employed to maximize the independent emissivity performance of the DBDOC in the MWIR and LWIR regions. The bicolor emissivity changes for the DBDOC are 0.80 and 0.46 in the MWIR (3-5 mu m) and LWIR (8-14 mu m) regions, respectively, with slight emissivity changes of 0.25 and 0.03 in the opposite regions. We experimentally demonstrate bicolor thermal imaging with different MWIR and LWIR information via independent emissivity regulation of MWIR and LWIR regions. We further validate gray-scale thermal imaging regulation in the LWIR region and the associated dynamic process at different heating temperatures in the MWIR region. The results demonstrate the experimental realization of independent thermal radiation regulation in the MWIR and LWIR regimes.