**2. SRS in microphotonics**

In this section, in order to describe stimulated Raman scattering investigations in microstructures, two crucial parameters have been individuated: dimension of microstructure and order/disorder degree of microstructure distribution. As to regard dimension of microstructure, in order to point out its role, in Section 2.1, SRS investigations in microcavities are reported. Concerning the order/disorder degree of microstructure distribution, we note that interesting developments have been recently demonstrated, which point out that it is possible to make use of the intrinsic order/disorder in photonic materials to create useful optical functionality [9]. In order to highlight the role of order/disorder degree of microstructure distribution, we describe two limit cases: in Section 2.2 SRS in photonics crystals, i.e. in a completely ordered structure, is reported, while in Section 2.3 SRS in random laser, i.e. in a disordered structure is described.
