With the continuing improvements in the high aver- age power operational capability of semiconductor laser diode arrays [ 11 and the development of diode laser radiance conditioning techniques [ 2,3], diode pump arrays that are scalable in absolute power and capable of delivering high intensity pump beams to the ends of rod or slab lasers are now available [4]. This development makes practical high average power (HAP) diode pumped solid state lasers (DPSSLs) using a diode end-pumping approach [ 51. Because this approach allows pump intensities greater than 20 kW/ cm2 to be generated, the laser designer can now seri- ously consider quasi-three level laser schemes for HAP DPSSL systems. Quasi-three level laser systems are ideally suited to the requirements of generating HAP laser outputs because they are characterized by low specific thermal generation parameters. The ability to