A broadband long-wavelength infrared all-dielectric metasurface absorber based on Mie resonance

Broadband metasurface absorbers operating in the long-wavelength infrared (LWIR) region have garnered significant interest due to their potential applications in thermal imaging, radiative cooling, microbolometers, and thermal camouflage. Here, we present a high-performance broadband LWIR absorber based on an all-dielectric metasurface absorber (ADMA), which exhibits polarization- and angle-insensitive properties. By synergistically combining Mie resonance effects with an impedance-matching mechanism between the ADMA structure and free space, the absorber achieves a high spectral average absorption of 96.2% across the 8-14 μm wavelength range. The highly symmetric geometry of the ADMA absorber ensures polarization-independent absorption at normal incidence. Under unpolarized light, the ADMA maintains angle insensitivity, retaining >85.4% absorption even at incident angles up to 50°. These results demonstrate the ADMA's superior optical performance in the LWIR region, highlighting its application potential, especially in infrared camouflage and microbolometers.