Photonic crystal slabs

We have applied the physical intuition of thin film optics to the modelling of photonic crystal slabs. The first three Chapters of this book present some basic concepts from thin film optics: Maxwell's equations, Fresnel reflection and transmission at a planar interface, reflection and transmission through a dielectric slab of finite thickness. Next, a matrix generalisation, to photonic crystal slabs, of the main scattering coefficients of thin films is derived by using a modal expansion method. The corresponding semi-analytic modelling technique provides insight into the physical mechanisms that are involved in the scattering properties of a photonic crystal slab. We have considered the simplified model of one-dimensional periodic structures, but most of the results can be easily adapted to more complex structures. As application, we have carried out a detailed study of the use of photonic crystal slabs to strongly enhance the intensity of an incident plane wave. Interestingly, the semi-analytic treatment has been previously applied to the photonic crystal slabs found in some living organisms (the cell wall of diatoms) and a large field enhancement was observed.