Lecture
This lecture covers advanced topics in optics, focusing on 2D photonic crystals and their band diagrams. The instructor explains the concept of reciprocal lattices, Brillouin zones, and specific points in the Brillouin zone. Different lattice structures, such as square and triangular, are discussed, along with their corresponding band diagrams and equifrequency curves. The lecture emphasizes the importance of understanding wave propagation in specific directions within the crystal lattice.