Single ultrathin dielectric-layer-coated Ti₃C₂ MXene for wide-angle polarization-insensitive perfect absorption in...

Ti₃C₂ MXene absorbers show high promise for use in the visible, terahertz, and microwave bands, but those used in the short-wave infrared (SWIR) spectra pose difficulties due to the high reflectivity. Herein, the perfect absorption of an ultrathin lossless dielectric-layer-covered Ti₃C₂ MXene substrate in SWIR regions is proposed and investigated theoretically based on the transfer matrix method. Wide-angle perfect or strong absorption within a certain wavelength range can be achieved by only selecting the proper ultrathin dielectrics (thickness « λ/4). In the central wavelength region, polarization-insensitive perfect absorption (>99%) with an incident angle less than 35° and strong absorption (>90%) with an incident angle less than 60° can be achieved. The feasibility of the design using a specific α-Si-coated Ti₃C₂ MXene structure is further elucidated. Our design's adaptability circumvents the requirement for expensive instrumentation and intricate fabrication processes, which can make Ti₃C₂ MXene materials applicable to large-scale manufacturing and practical implementation in the SWIR region.