Optimization of extremely broadband terahertz absorber based on multilayered doped silicon film

We demonstrated numerically a multilayered broadband nearly perfect absorber in terahertz frequencies. The structure is composed of multilayered doped silicon film. Transfer matrix method and genetic algorithm are utilized to simulate and optimize the absorption property. The 20 dB attenuation bandwidth of this structure is larger than 94%, while 40 dB attenuation bandwidth is also larger than 50%. Compared with previous multilayered absorbers based on resistive metal, the structure proposed here shows better performance and is easier to fabricate.