Random Light Scattering

Abstract

This chapter presents optical properties of surface textures without any long range order in their geometry. Such textures are usually called random, as opposed to periodic ones like gratings. The random nature is extremely beneficial for applications where the optical response extends over a wide frequency range; suitable operation over an extended spectral domain is thus ensured by the absence of a preferential period, which would otherwise yield undesired selectivity of light scattering into a certain angle for a fixed frequency. To introduce the reader to this burgeoning field in the context of amorphous nanophotonics, this chapter starts by briefly introducing volume and surface scattering. After introducing a few random surface textures of technological importance, Sect. 11.3 discusses the statistical description of random surfaces in terms of root mean square roughness and autocorrelation length. Light scattering is discussed in terms of scalar scattering theory in Sect. 11.4. In Sect. 11.5 a Fourier theory is presented which avoids some of the limitations of scalar theory. Finally, Sect. 11.6 illustrates the application of random surfaces and the description of their scattering properties in thin film solar cells.