Light-scattering measurements have enabled us to determine that the tr
ansition to sonoluminescence is characterized by a bifurcation in the
dynamics of a trapped pulsating bubble. These experiments also reveal
that in the sonoluminescence (SL) state, changes in bubble radius of o
nly 20% are associated with factors of 200 in the intensity of emitted
light. This sensitivity of SL suggests that it originates from the ki
nd of singular behavior that arises from the implosion of a shock wave
. Theoretical extrapolations of this model to energy scales for fusion
are discussed.