The overall effect (in particular with regard to this light emission, which really happens – it's not just apparent) is mostly investigated under the name sonoluminescence.
Though the process of this luminescence itself remeansremains unsettled, it is for sure that extremely high temperatures are produced at a bubble collapse (in fact, it was conjectured they might be hot enough to build a nuclear fusion reactor!), and this high temperature obviously causes another steam bubble to form very quickly, so that would explain the pulse-oscillation effect.
