Diode-pumped Nd:YAG laser for precision laser machining

Results are presented on a high power, diode-pumped, pulsed Nd:YAG laser for precision laser machining, The laser is an unstable resonator with a graded reflectivity outcoupler, generating a beam with excellent beam quality, The gain medium is a single zig-zag slab, pumped symmetrically by diode arrays. The use of diode arrays minimizes the thermal loading on the slab, and the zig-zag path averages thermal distortions in the zig-zag dimension. Measurements of beam divergence as a function of diode duty-cycle will be presented, Available pulse formats will also be discussed, To date, the laser has produced 720 W at 20% diode duty-cycle with a stable cavity and 550 W at 20% duty cycle with an unstable cavity in close agreement with model predictions, The beam divergence has been measured to be 1.7 times diffraction-limited at 20% duty cycle, The laser has been operated with pulse lengths from 20 mu s to 1 ms and is being used to obtain laser processing data, with some results shown.