Optical emissions in a sonoluminescing bubble

Rie study how the mechanism of spontaneous decay of atoms (or molecules) in a sonoluminescing bubble (SLB) can be affected by the high density and hig h temperature environment resulting from the rapid collapse of the gas bubb le immediately prior to light emission. We present a detailed study of the density of states of photons in multiple-layered spheres, which mimic Vario us stages of a SLB. In particular, we found that the spontaneous decay rate could be strongly enhanced in the presence of a thin plasma shell inside t he bubble, which was predicted recently in numerical hydrodynamic simulatio ns of a SLB.