Abstract

Scaling diode-pumped solid-state lasers to multiwatt average power levels is an area that has attracted growing interest over recent years, stimulated by the wide commercial availability and relatively low cost of high-power cw diode-bar pump sources. Recent developments in this area have included; efficient, TEM₀₀, end-pumped Nd:YVOV₄ and side- pumped Nd:YLF lasers at 1.064 µm¹ and 1.047 µm² respectively with cw powers in excess of 13 W. So far, the scaling of diode-pumped solid-state lasers to >10 W average power, while retaining high overall efficiency has generally been restricted to only the highest gain Nd transitions. Extension of efficient high-average-power operation to include other useful, but lower gain, transitions such as the 1.053-µm transition in Nd:YLF, has been hindered by the inconvenient shape of the diode bar's output beam. The diode bar, with its highly elongated emitting region produces an output having M² beam quality factors ~1 in the plane perpendicular to the array, but >1000 in the plane of the array. It is, therefore, difficult to focus to the small beam sizes required, particularly for low-gain transitions in efficient end-pumped configurations.

© 1996 Optical Society of America