Diode-pumped laser

A laser apparatus comprising:

• a laser diode having an output laser facet for emitting an astigmatic pump beam at a first wavelength along an optical axis, the astigmatic pump beam having a substantially circular cross-section at a first location along the optical axes;
• first and second reflectors disposed sequentially along the optical axis for receiving the astigmatic pump beam through the first reflector, said first and second reflectors forming a laser cavity therebetween;
• and,
• a gain element having a first end and a second end, said first end facing the laser diode and spaced apart from the output facet thereof in the absence of lens elements therebetween, wherein the gain element is disposed 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;
• and,
• wherein the first end of the gain element is located between the first location and the laser diode at a distance of at least 0.001″ from the output facet of the laser diode, said distance selected for maximizing output efficiency of the laser apparatus in the absence of collimating and focusing elements between the laser diode and the gain element.

A laser apparatus comprising:

• a laser diode having an output laser facet for emitting an astigmatic pump beam along an optical axis, the pump beam having an aspect ratio;
• and,
• first and second reflectors disposed sequentially along the optical axis and forming a laser cavity therebetween;
• and,
• a gain element disposed along the optical axis between the first and second reflectors, the gain element having a first end for receiving the astigmatic pump beam and a second end for emitting a laser beam, said first end facing the output facet of the laser diode and spaced apart therefrom by a distance 1 of at least 0.001″ in the absence of lens elements therebetween;
• and,
• wherein the aspect ratio of the pump beam is reduced from a value of at least 20 at the output facet of the laser diode to a value of at most 6 at the first end of the gain element;
• and,
• wherein the distance l is selected for optimizing at least one of output efficiency of the laser apparatus and a shape of the laser beam in the absence of collimating and focusing elements between the laser diode and the gain element.