  Designing broadband metamaterial perfect absorbers is challenging due to the
intrinsically narrow bandwidth of surface plasmon resonances. Here, the paper
reports an ultra-broadband metamaterial absorber by using space filling Gosper
curve. The optimized result shows an average absorptivity of 95.78% from 2.64
to 9.79 {\mu}m across the entire mid-infrared region. Meanwhile, the absorber
shows insensitivity to the polarization angle and the incident angle of the
incident light. The underlying physical principles, used in our broadband
absorber, involve a fractal geometry with multiple scales and a dissipative
plasmonic crystal. The broadband perfect absorption can be attributed to
multiple electric resonances at different wavelengths supported by a few
segments in the defined Gosper curve.
