A Metallic Glass-Based Dual-Band-Selective Emitter with Near-Perfect Absorption in Atmospheric Windows

A new trilayered structure design of metallic glass film was proposed and demonstrated to achieve near-perfect dual-band-selective absorptions within mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) bands in atmospheric windows. A metal-insulator-metal (MIM) structure was used as a selective absorber for decades; however, due to the highly reflective properties of metal in the infrared region, the structure was difficult to apply within the mid- and long-infrared region. By applying the metallic glass film as a top layer, the asymmetric metallic glass-insulator-metal (MGIM) structure could display remarkably high absorptance in the mid-IR region, a distinct feature that a conventional metal-insulator-metal (MIM) structure could not achieve. In addition, the MGIM structure exhibited outstanding omnidirectional properties. The fabricated MGIM structure exhibited near-unity absorptions within MWIR and LWIR atmospheric windows, with an absorptance of 96.7% and 98.8% at peak wavelengths of 3.9 and 10.8 μm, respectively. These remarkable characteristics of the AlNiY-based MGIM structure make it highly promising for heat dissipation applications. The MGIM structure showed better radiative cooling performance than typical MIM emitters and an ideal broadband emitter. Furthermore, compared with other dual-band emitters that utilize complex metamaterial structures, the lithography-free process of our approach dramatically reduces the cost and simplifies the processes.