Increased brightness in pumping schemes using diode bars

Summary form only. Diode bar curvature, also called "smile", is known to limit the brightness achievable in commonly used pumping schemes. A correction for this curvature would prove useful for side-pumped solid-state lasers or whenever the curvature of the pump beam causes a bad overlap with the intra-cavity beam. We show that by introducing a tilted, cylindrical collimating lens in front of the diode bar, the curvature of the diode\´s beam can be reduced, and the beam quality increased by more than 100%. Moreover, when this correction mechanism is used in conjunction with a beam shaper, the total pump power of the set-up is increased because clipping of the pump power at the beam shaper is reduced due to better beam quality. The basic mechanism is that the center part of the diode radiation becomes shifted more upwards than the more lateral parts of the radiation due to the thicker center part of the tilted lens.