Genetic algorithm-enhanced design of ultra-broadband tunable terahertz metasurface absorber

In this paper, we demonstrate an ultra-broadband tunable metasurface absorber and investigate the automation of its design process, avoiding the traditional manual trial-and-error process. Here, automation is achieved by controlling the random coding structure of the VO2 layer by genetic algorithm. Subsequently, the bandwidth of the metasurface absorber is enlarged by a structural design forming a Fabry-Perot cavity. The genetic algorithm-enhanced metasurface absorber absorption bandwidth ranges from 1.84 to 8.36 THz, with a relative bandwidth of up to 127.8 %. The maximum absorption can be tuned from 4 % to 100 % by controlling the conductivity of VO2 through temperature. Our results may provide guidance for the automated design studies of ultra-broadband tunable terahertz metasurface absorbers.