Abstract

The rare-earth ion Yb³⁺ has attracted attention within the diode-pumped solid-state laser community chiefly because its favorable quantum defect (from the InGaAs-diode-pumpable absorption feature at 941 nm and the lasing transition at 1.03 μm) creates the lowest known thermal load¹ of any 1-μm laser dopant (i.e., 1/4 that of Nd:YAG). Moreover, its simple two-electronic-manifold spectroscopic character eliminates competing processes, such as excited-state absorption and upconversion, from degrading its laser performance. For high-average-power laser applications, YAG is the laser host material of choice because of its thermal ruggedness. Diode-pumped Yb:YAG lasers have been reported in various end-pumped geometries,^2,3 with slope efficiencies up to 80% with respect to absorbed power.⁴ One way to scale the Yb:YAG laser performance to higher average power is to implement a transverse- or side-diode-pumped geometry by using rack-and-stack diode pump arrays, for example. Utilizing this pump geometry, we recently reported⁵ what is to our knowledge the highest pulse energy to date of 50 mJ/pulse in the first side-diode-pumped Yb:YAG laser demonstration, and we have now modified this laser for AO Q-switching operation.

© 1995 Optical Society of America