Fig. 1. Developing layers of Grating Designer

Fig. 2. Medium region division of Grating Designer

Fig. 3. Process of calculating and designing grating of Grating Designer software

Fig. 4. Main interface of Grating Designer

Fig. 5. Grating Designer generates three triangular gratings only by changing bottom duty. (a) 0.3; (b) 0.6; (c) 0.9

Fig. 6. Configuration of sinusoidal grating by Grating Designer. (a) Cladding layer; (b) internal film layer; (c) external film layer

Fig. 7. Three-layer CMM broadband metasurface terahertz filter structure designed by Grating Designer. (a) Metal layer; (b) dielectric layer; (c) metal layer

Fig. 8. Grating Designer generates complex structures by symmetry and cross transition

Fig. 9. Diffraction order and efficiency. (a) Lattice plot; (b) bar chart; (c) polar plot; (d) table representation

Fig. 10. Comparison of calculated diffraction order and efficiency. (a) Gsolver; (b) VirtualLab; (c) Grating Designer

Fig. 11. Field analysis and display functions of Grating Designer. (a) Cross-sectional field distribution; (b) cross-sectional phase distribution; (c) 2D field distribution

Fig. 12. Grating Designer performs parameter scans for wavelength and incident angle simultaneously. (a) Change in sum of reflectance; (b) change in diffraction efficiency of -1 order transmission field; (c) change in sum of transmissivity; (d) change in angular resolution