Abstract

Photonic crystals (PhCs) are structures characterized by a spatially periodic dielectric function and are nowadays very appealing due to their rich physics. The occurrence of photonic band gaps, i.e. frequency regions where propagation of light is strongly inhibited make PhCs interesting for many applications. Furthermore, the present accurate engineering of photonic states in PhCs, gives the possibility to probe both the weak and strong coupling regimes of light-matter coupling. For the former limit, we examine the modifications of the spontaneous emission from a dipole embedded in a generic one-dimensional (1D) photonic structure, and we show a model derived within a quantum-electrodynamical formalism, discussing its extension to two-dimensional PhCs (like Photonic Crystal slabs). For the strong-coupling regime, we analyze some interesting features of exciton-polariton states resulting from (i) bulk excitons and the photonic modes in a 1D Bragg grating and (ii) quantum well excitons and the photonic modes of a (2D) PhC slab.