High-power, low-SMILE vertical stack diode laser bars enable better laser cladding

摘要

A low near-field nonlinearity (low-SMILE); 32-bar diode stack produces a 8 kW uniform flat-top beam for cladding applications. High-power diode lasers play a major role in materials processing. Compared to conventional carbon dioxide (CO_2) lasers, high-power direct-diode laser sources have great advantages, such as high efficiency, low cost, wavelength versatility, and high reliability. High-power diode lasers, with a 9xx nm wavelength much shorter than that of CO_2 lasers, increases the absorption of the metal surface and improves the melting efficiency. However, the large SMILE effect, of which the emitters are vertically displaced in a laser diode bar, causes poor output beam quality. Laser diode array bowing in the fast axis increases the geometrical line width of the output line when creating a line by colli mating and focusing an emitting light from a laser array in the fast axis. The poor output beam quality of direct diode lasers is a large obstacle in industrial applications (see Fig. 1).