A hydrodynamically optimized mixer module, to be coupled to a deterministic hydrodynamic tool that allows pulsed polishing of optical surfaces is described. This module allows the supply of abrasive foam or fluid that enters the tool to be interrupted without impairing the operational stability of the polishing process and of said hydrodynamic tool. The mixer module includes at least one interrupter element for switching high-velocity fluids; a first inlet through which air is injected under pressure and in a controlled manner; a second inlet through which a polishing fluid is injected in a controlled manner, said polishing fluid filling a predetermined volume with a hydrodynamically optimized shape and being transferred to a mixing zone where, together with the pressure-injected air, an abrasive foam is produced that is injected into at least one rotational acceleration chamber of the hydrodynamic tool to which the mixer module is coupled.