Executable Program for Calculating Scattering and Transmission of 2D Photonic Crystals Using FDTD Method

The Finite-Difference Time-Domain (FDTD) method serves as an effective numerical tool for calculating optical properties of photonic crystals, demonstrating particular efficiency when analyzing scattering and transmission behaviors in two-dimensional structures. This executable program directly solves Maxwell's equations through spatial and temporal discretization, enabling intuitive simulation of electromagnetic wave interactions with periodic dielectric structures.

The core program logic revolves around a 2D simplification within three-dimensional space: Grid Discretization: Implements Yee lattice discretization to digitally model dielectric constant distribution, with the code handling epsilon value assignments to each grid cell. Boundary Treatment: Utilizes Perfectly Matched Layer (PML) absorbing boundary conditions, where the code implements complex coordinate stretching to minimize non-physical reflections that could compromise calculation accuracy. Excitation Source Configuration: Supports both Gaussian pulse and continuous wave excitation through source injection algorithms, with real-time recording of electric and magnetic field component evolution in the time domain. Post-processing Module: Performs Fourier transform on time-domain data using FFT algorithms to extract scattering field intensity and transmission spectra in the frequency domain.

Users can customize parameters through input file modifications: Lattice type (square, triangular, etc.) Dielectric rod geometry and refractive index Light source incidence angle and polarization Detection region positioning

The software's advantage lies in packaging complex FDTD workflows into black-box operations, making it suitable for rapid verification of photonic crystal bandgap characteristics or defect state manipulation effects. It serves as a practical auxiliary tool for photonic device design, with the code structure allowing easy parameter sweeps and batch processing for systematic studies.