Any single bubble collapse, since it involves the generation of light, must involve an electromagnetic pulse no matter how small. Therefore if two events occur at precisely the same time, then in the direction described by the two position / events, a wavelength is illustrated. Same as any EM radiation, that would infer a frequency by simple light-speed equation. If we consider the case for just two such events, assuming that it were possible to generate them, then the propagation of that frequency / wavelength would also be extremely (if not perfectly) directional. The resultant (directional) E.M. pulsing could thus be represented:-