Patent ID: 7260133

Claim:
A laser apparatus comprising: a laser diode having an output facet for emitting an astigmatic pump beam at a first wavelength along an optical axis, the astigmatic pump beam having an elliptical non-circular shape characterized by an aspect ratio of at least 20 at the output facet and a substantially circular shape at a first location along the optical axis; and, a gain element having a first end and a second end, said gain element disposed longitudinally along the optical axis for receiving the astigmatic pump beam through the first end and for emitting a laser beam through the second end at a second wavelength; wherein the first end of the gain element is spaced apart from the output light-emitting facet of the laser diode, in the absence of lens elements therebetween, by a distance l having a value between 30 μm and 170 μm, said distance l being such that the aspect ratio of the astigmatic pump beam is reduced to a value of at most 6 at the first end of the gain element.