Polarization-insensitive, wide-angle, high bandwidth vanadium nitride-based infrared nanostructured absorber

This paper investigates the potential of a transition metal nitride, Vanadium Nitride (VN), in designing a nanostructured absorber for infrared wavelengths. A simple and plain nano circular ring composed of VN is printed over a metal-backed lossy substrate to implement broadband absorber. The proposed VN-based absorber offers an exceptional absorption characteristic across the large operating wavelength from 1000 to 2400 nm with an absorption threshold of 90%. The absorption properties of this VN absorber have also been analyzed by varying the oblique angles of the optical light and it exhibits a good absorption value of more than 70% even at theta = 60 degrees. Due to the symmetry in the nano-ring of VN, it also achieves the polarization-insensitive response by varying the rotation angles (polarization angles). Moreover, the multi-reflection interference theory has been introduced to verify the simulation results of the proposed VN-absorber. Because of its thermal robustness, mechanical stability, and wide absorption bandwidth, it holds promise for applications in solar cells and thermophotovoltaics.