Abstract

Diode-pumped, solid-state lasers (DPSSL) are synonymous with compactness, high efficiency, and very good reliability. Advances made in recent years in both AlGaAs diode material and cooling techniques¹ have led to the operation of diode arrays at greater than 70-W cw output power.^1,2 Needless to say, these high-power arrays are becoming increasingly attractive as pump sources to designers of high-power DPSSL. These bars can be scaled to very-high-power, large-area, pump arrays by configuring them in what is called a two-dimensional (2-D) "rack and stack" architecture. Sizes of these 2-D arrays range anywhere from 0.3 cm x l cm for rod pump geometries to 2 an x 8 an for slab pumping geometries.³ Peak power densities of 5 kW cm^{-2 4} and average power densities of 9.5 kW cm^{-2 5} have been reported using microlenslet arrays and fiber-coupled bars, respectively. Recent interests involving pumping of three-level lasers, where high intensities are needed, using high-power diode arrays directly in a broad range of thermal material processing applications, and in end pumping of various solid-state crystalline laser media, have focused our research on higher efficiency micro-optics as well as a simple and efficient macro-optic coupling system. Figure 1 shows such a system being utilized to end pump a Nd⁺³:YLF laser rod. The pump array is made up of 60 1-cm long AlGaAs diode bars that are mounted on silicon (Si) microchannel cooled (MCC) heatsinks, a technology well developed at Lawrence Livermore National Laboratory.¹

© 1993 Optical Society of America