Bi-directional & multi-functional terahertz beam splitter with stacked configuration

A novel bi-directional & multi-functional terahertz beam splitter with stacked configuration is proposed in this paper, which can be used for dual- to five-port output with high total diffraction efficiency and satisfactory efficiency uniformity optical controller in 2.52 THz band. By applying rigorous coupled-wave analysis and simulated annealing algorithm, the diffraction efficiency of each order of the proposed structure is optimized to be greater than 48%, 32%, 24%, and 19% for dual- to five-port output, respectively. Compared with other 1D/2D beam splitters reported recently, our work not only improves the diffraction efficiency of each port and ensures good uniformity, but also provides multiple efficiency output modes (from dual- to five-port output) in the same structure, which is very beneficial for its integration into devices with multiple requirements and greatly ameliorate the signal-to-noise ratio in practice. Graphical abstract