A highly efficient pumping configuration for a solid state laser uses a diode bar pumping source producing optical energy coherent along an axis normal to the plane of the diode junctions. Pump energy is nearly collimated by a cylindrical optical fiber and applied through a minimum width injection port to a low absorption solid state laser rod in a highly reflective optical cavity including a cylindrical sleeve forming a coolant chamber around the laser rod. The nearly collimated energy is focussed to a minimum width in the plane of the injection port in order to minimize the loss of energy from the optical chamber by leakage out through the port. The laser rod is substantially evenly illuminated by the entire energy entering the cavity on the first pass. Optical energy not absorbed during illumination through is reflected within the cavity until substantially absorbed by the solid state laser rod.