Sonoluminescence in granular media

Abstract

We report an experimental observation of sonoluminescence (SL) from ZnS:Mn and ZnS granular mixtures. The mechanism of SL is suggested to arise from a grain collision-induced excitation of electrons and holes recombining through defect states located in the near surface regions of the grains. Pressure-induced broadening and thermal phenomenon are likely involved in producing broad emission bands of observed SL. A heterogeneous spatial distribution of SL is suggestive of a grain aggregation at acoustic driving. A simplified description of grain movements in the framework of continuum mechanics approach yields an accurate account of the observations. The SL phenomenon may be useful in gaining insight into the dynamical behavior of granular media.