Design of Ultra-Broadband Metamaterial Absorber from Visible to Infrared Region

We have developed an ultra-broadband metamaterial absorber (UBMA) based on impedance matching. The absorber of the UBMA has an absorption of more than 90% in the wavelength range of 300–4000 nm (absorption bandwidth of 3700 nm), which can cover the visible and infrared regions. When the absorption is greater than 95%, the absorption bandwidth of the UBMA can reach 3440 nm. The designed UMBA has polarization-insensitive and wide-angle absorption characteristics, and the average absorption of the transverse magnetic (TM) and transverse electric (TE) modes at 60° oblique incidence are 94.7% and 86.8%, respectively. The physical mechanism suggests that surface plasmon resonance, localized surface plasmon resonance, and cavity resonance interactions jointly dominate the broadband and high absorption characteristics. The ultra-broadband and high absorption absorber we have designed have potential applications in energy harvesting, thermoelectric applications, and detection.