Abstract: A transverse pumping system for a laser rod uses symmetrically arranged banks of laser diodes which create overlapping patterns of illumination inside the rod. Cooling is provided by a symmetrically constructed circulation system which directs a turbulent flow of cooling water against the laser rod and against a heat sink for the diode banks. Cooling water for the laser rod flows through a glass tube surrounding the rod. This enables the cooling water to perform an auxiliary function in focussing the illumination generated by the pumping diodes.