Lecture
This lecture covers advanced topics in optics, focusing on photonic bandgaps in different structures such as dielectric spheres on a diamond lattice and common 2D lattices like square lattice of holes and pillars. The instructor discusses the factors influencing the existence of bandgaps, including filling factor and dielectric contrast. Scaling laws for producing different band structures at various frequencies are also explained. The lecture delves into band structures in reciprocal space, emphasizing the non-overlapping forbidden bands and the rarity of full bandgaps. Various examples and illustrations are provided throughout the presentation.