Methods for modifying the physical, chemical and/or biological properties of a fluid by irradiation are provided. In one embodiment, a method comprising supplying a flow of a fluid to an irradiation chamber focusing the flow of the fluid so as to create at least one fluid layer and applying radiation to the fluid layer in a defined portion of the irradiation chamber thereby modifying at least one physical, chemical or biological property of the fluid layer is provided. Systems for the implementation of such methods are also provided.
