Coherent backscattering from finite and wavelength-scale disordered structures

Coherent Backscattering (CBS) has been observed over very narrow angular ranges in various types of large, disordered structures, as shown in both numerical and experimental studies. An interesting and less-studied situation, however, is the case of finite disordered structures with sizes on the order of a few tens of wavelengths. In this work, we investigate the formation of CBS in such structures through full-vectorial analysis of several random and sparse configurations. We report the formation of the CBS signature, while a wider cone, associated with the finite size of the structure, is observed. We focus both on the formation and the convergence behavior of the CBS cone, providing important insights for future experimental studies. In addition, the effect of key parameters such as density factor, size, and number of particles are investigated in connection with the scattering response. Our detailed investigations can lead to new diagnostic tools for characterization of semi-randomized and finite, sparse, random geometries.