Abstract
We demonstrate an ultra-broadband, ultra-thin, polarization insensitive, wide-angle, single-layer planar metasurface THz absorber by integrating different Cayley tree fractal resonators into one supercell based on the frequency shifting and multi-resonance bands of different fractal orders. The proposed absorber provides wide incident wave angle with absorption bandwidth of more than one octave, i.e., 3.23 THz. The calculated absorption efficiency remains above 80% for a bandwidth of 2.62 THz. This work is a step forward in realizing perfect blackbody absorbers and sensors in THz regime.