Ultra-broadband polarisation-insensitive far infrared absorber based on an umbrella tungsten array structure

The technical study of metamaterial broadband perfect absorbers is gradually gaining widespread attention in the ongoing research. Due to its different aspects such as high absorption, frequency selectivity and ease of design, its application in various fields is showing more and more possibilities and prospects. In this research project, we propose an ultrabroadband, polarisation-insensitive​ metamaterial terahertz absorber based on an umbrella absorption cell that can be used as a far-infrared absorber, which uses tungsten (W) refractory metal as the absorber layer. From the results of our simulations, we can see that the absorber can achieve an absorption bandwidth of 3.3–15 THz, and the average absorption of the absorber can reach more than 99.0%. The absorber has a large absorbance in the far-infrared band and can be considered as a far-infrared absorber. •The broadband terahertz absorber achieves absorption with an absorption bandwidth of 11.7 THz and an absorption rate of over 99%, approaching perfect absorption.•Perfect absorption is possible in the far-infrared wavelength band and can be fabricated as far-infrared absorbers.•The absorber is insensitive to both the angle of polarisation and the angle of incidence.