Chapter 4: Wave optics and FDTD simulations

This chapter focuses on finite-difference time-domain (FDTD) simulation in OghmaNano. FDTD is a full-wave electromagnetic simulation method for modelling how electromagnetic fields propagate, scatter, interfere, reflect, and evolve with time in photonic and optical structures.

The chapter is organised around practical, runnable FDTD simulation tutorials, progressing from basic electromagnetic wave propagation to more complex photonic structures including waveguides, photonic crystals, Bragg gratings, resonators, optical cavities, interference systems, and integrated optical devices. Examples cover FDTD light sources, boundary conditions, detectors, pulse propagation, diffraction, resonant energy build-up, transmission, reflection, field confinement, and time-domain energy flow. Each example is designed to be directly runnable in OghmaNano, allowing users to move from FDTD simulation setup to quantitative analysis of electromagnetic and optical device behaviour.