Abstract: A laser pump cavity assembly having a laser rod with a ground outer surface positioned concentrically within an annular jet sleeve which is, in turn, positioned concentrically within an annular outer sleeve. The outer sleeve is coated with a dielectric coating having slits therein arranged to receive focused optical pump radiation from respective laser diode arrays, the pump radiation being transmitted through the outer sleeve and jet sleeve to excite the laser rod. The jet sleeve is positioned to define cooling fluid chambers between the outer sleeve and the jet sleeve, and between the jet sleeve and the laser rod, and is provided with a series of jet holes for directing cooling fluid to impinge perpendicularly on the laser rod. The end faces of the jet sleeve and outer sleeve are further coated with dielectric material to enhance the efficiency of the device. The cooperating end caps which mount the outer sleeve, jet sleeve, and laser rod employ a number of advantageous self-aligning and sealing features.