High-power diode-bar-pumped Nd:YLF laser at 1.053-µm

Abstract

Scaling diode-pumped solid-state lasers to multiwatt average power levels is an area which 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:YVO4 and side-pumped Nd:YLF lasers at 1.064µm and 1.047µm respectively with cw powers in excess of 13W. So far, the scaling of diode-pumped solid-state lasers to >10W average power, whilst 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 1.053µm 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