Compact terahertz wave beam splitter based on self-collimating photonic crystals

In this paper, a compact beam splitter is proposed for terahertz (THz) systems based on the self-collimation effect in two-dimensional photonic crystals (PCs). The splitter has a very compact size of 908×908μm2. The parameters of the splitter are optimized by using the plane wave expansion (PWE) method. The equal-frequency contours (EFCs) and gap map are given to analyze the properties of the splitter. By using the finite-difference time-domain (FDTD) method, the field distribution of the THz wave propagation in the structure is simulated and the normalized transmitted powers versus various radii of the air holes of the splitting region are calculated. The impact of incident angles on the transmitted power is also studied with the FDTD method.