This condensed matter physics project involves theoretical and complementary microwave and optical investigations of wave propagation in random structures. The essentials of mesoscopic physics are explored by exploiting the analogy between electromagnetic propagation and electronic conductance. Statistical distributions and correlations in the local field and in global quantities such as the transmission and conductance in translucent, diffusing and localizing samples will be studied and characterized. The dimensionless conductance is changed by varying the scattering medium and its length and diameter and by tuning through the mobility edge in periodic metallic networks filled with random mixture of scatterers. Universal aspects of wave dynamic are revealed in the statistics of the phase of the transmitted field. The possibilities of acousto-optic imaging use diffuse light and the nature and applications of lasing in random systems will be investigates. %%% Classical wave propagation is the means by which we probe our environment and communicate with one another. The proposal explores the fundamental statistic of light and microwave propagation in collections of samples with statiscally equivalent disorder. It will establish the connection between the statistics of the local fields and the total transmitt3ed radiation and the optic conductance. This will improve our understanding of wave propagation and of giant fluctuation in transmission and conductance which occur in the transition from a situation in which waves can propagate to one in which transport is inhibited. It is thus a useful model of electronic transport in microcircuit which are of increasing importance in modern electronics. The possibilities of acousto-optic imaging using diffuse light as a noninvasive mammography modality will be investigated. The characteristics and applications of lasing in random systems will also be explored. ***
